Severe T-cell immunodeficiency after solid organ or bone marrow transplantation may result in the uncontrolled outgrowth of latently Epstein-Barr virus–infected B cells, leading to B-lymphoproliferative disorder (BLPD). Given the potentially important pathogenic role of IL-6 in BLPD, it was tested whether the in vivo neutralization of IL-6 by a monoclonal anti–IL-6 antibody could contribute to the control of BLPD. Safety and efficacy were assessed in 12 recipients of transplanted organs who had BLPD refractory to the reduction of immunosuppression over 8 days. Five patients received 0.4 mg/kg per day. The next 7 patients received 0.8 mg/kg per day. Treatment was scheduled to last 15 days. It was completed in 10 patients, and in the other 2 patients was discontinued early (days 10 and 13, respectively) because of disease progression. Treatment tolerance was good, and no major side effects were observed. High C-reactive protein levels were found in 9 patients before treatment but were normalized under treatment in all patients, demonstrating efficient IL-6 neutralization. Complete remission (CR) was observed in 5 patients and partial remission (PR) in 3 patients. Relapse was observed in 1 of these 8 patients in whom remission was observed. This relapse was unresponsive to treatment. Disease was stable in 1 patient, but it progressed in 3 patients. Seven patients are alive and well. Two patients died because of disease progression, and 3 patients died while in CR (chronic rejection in 2 patients and BLPD sequelae in 1 patient). These data suggest that the anti–IL-6 antibody is safe and should be further explored in the treatment of BLPD.

Introduction

B-lymphoproliferative disorder (BLPD) is a severe complication of organ and bone marrow transplantation (BMT) caused by the Epstein-Barr virus (EBV).1-7 EBV latently infects B cells, which become immortalized by expressing part of the viral genome that persists in an episomal form.8 The growth of EBV-infected B cells is controlled by cytotoxic T cells.9In vivo severe T-cell immunodeficiency, such as occurs in patients with inherited cellular immunodeficiency10 or acquired immunodeficiency syndrome11 and in recipients of solid organ or bone marrow transplants,12-14 may result in the uncontrolled outgrowth of EBV-infected B cells, leading to BLPD. BLPD occurs in 1% to 15% of organ recipients and in 0.5% to 24% of bone marrow recipients, depending on the type of transplantation, the ages of donor and recipient, the intensity of immunosuppression, and the method of T-cell depletion.15-18 The overall prognosis of BLPD is poor, and the disease is fatal in 40% to 60% of affected recipients of transplanted organs15,19-22 and in 90% of affected BMT recipients.15,23-25 Treatment strategy is still controversial. Antiviral therapy (acyclovir, ganciclovir) is ineffective at preventing the persistence of episomal EBV associated with the latent phase. Although such treatment has not been definitively shown to be effective against BLPD, remission has occasionally been reported.15,26 Chemotherapy and radiotherapy are of limited value, at least in early-onset EBV-associated BLPD.15,27 Surgery may save the patient's life in cases of localized BLPD.15 Preliminary data have suggested improved survival with the use of interferon-α and the intravenous infusion of high-dose immunoglobulins.28 For BLPD occurring after BMT, the infusion of donor T lymphocytes or EBV-specific donor cytotoxic T lymphocytes can be effective in bringing B-cell proliferation under control.12,29 The use of anti–B-cell monoclonal antibodies (mAbs) (anti-CD24 and anti-CD21) appeared to be a safe and relatively efficient therapy for post-transplant early-onset BLPD.30-32 However, these anti–B-cell mAbs are no longer available. The use of a humanized anti-CD20 mAb may be an attractive alternative, as recently reported in a small number of patients.33-35 

We investigated the effect of a monoclonal anti–interleukin-6 (IL-6) antibody on B-cell growth in patients with BLPD. IL-6 is a multifunctional cytokine produced by monocytes, fibroblasts, endothelial cells, and other cell types. It plays an important role in the proliferation and maturation of B cells.36-39Overproduction of this cytokine is thought to be involved in the pathogenesis of lymphoid malignancies, high-grade B-cell lymphomas,40,41 and myelomas42-44 in particular. It has also been shown that IL-6 promotes the growth of EBV-infected B cells,45,46 that patients with BLPD produce abnormally high levels of IL-6,45,47 and that B-cell lines derived from BLPD express the p80 chain of the IL-6 receptor.48 In addition, the transfection of EBV-transformed B cells with human IL-6 cDNA greatly increases the proliferation of these cells both in vivo and in vitro.49,50 Durandy et al48 showed that anti–IL-6 mAb could inhibit the growth of several BLPD-derived B-cell lines in severe combined immunodeficiency disease (SCID) mice in vivo. This treatment led to complete remission in most mice and to tumor-free, long-term survival in 40% of mice.

Given the probable importance of IL-6 in BLPD pathogenesis, we tested, in a phase 1-2 clinical trial, the toxicity and efficacy of anti–IL-6 mAb treatment against BLPD occurring after organ transplantation. We report here the results of a trial in 12 patients.

Materials and methods

Monoclonal anti–IL-6 antibody

The mouse monoclonal anti–IL-6 antibody (B-E8)51was produced and supplied by Diaclone (Besançon, France; specific activity, 1 μg B-E8 neutralizes 6000 U IL-6).

Protocol design

This study consisted of a multicenter phase 1-2 trial of monoclonal anti–IL-6 antibody administration to patients with post-transplant BLPD. Detailed informed consent was obtained from all patients or from parents of children younger than 10 years of age, in accordance with French legislation and as approved by the ethics committee of Necker Hospital (Paris, France). We evaluated anti–IL-6 antibody-related toxicity and effects on BLPD.

Patient enrollment

BLPD was diagnosed based on the presence of a lymphoproliferative syndrome with detectable tumors consisting of EBV-positive B lymphocytes. EBV was detected immunohistologically, with anti-LMP antibodies, by polymerase chain reaction (PCR) detection of the EBV genome, or by Southern blot analysis or by in situ hybridization (see below).

For inclusion in the study, patients could be of any age but had to have acquired BLPD after organ transplantation and to have satisfied at least one of the following criteria: (1) be unresponsive to the tapering of immunosuppression for a minimum of 8 days; (2) have histologically invasive disease with nodal capsule disruption; (3) have rapidly progressive multiple lymphoproliferative lesions, excluding those from surgery. BLPD unresponsive to the tapering of immunosuppression treatment for a minimum of 8 days was defined as no change in C-reactive protein (CRP) level, fever, or other general manifestations, and no decrease in tumor size detected by clinical assessment and appropriate imaging tests.

No other BLPD treatments were given in association with the anti–IL-6 antibody. If disease progression was observed during the administration of anti–IL-6 antibody, treatment could be stopped and another treatment could be proposed. Twelve patients were included in the study between September 1995 and August 1998. The final data were collected on June 30, 1999.

Anti–IL-6 antibody dose and administration

The monoclonal anti–IL-6 antibody BE-8 was diluted in 2 mL/kg 5% glucose serum and administered as a 30-minute intravenous infusion once a day for 15 days. To evaluate toxicity and the dose dependency of the effects of the anti–IL-6 antibody, a dose escalation trial was performed. Patients 1 to 3 received a dose of 0.4 mg/kg per day. Patients 4 and 5 received a 1 mg/kg bolus on day 1, which was followed by injections of 0.4 mg/kg per day. These doses were well tolerated (see “Results”); hence, the remaining 7 patients received a third regimen consisting of a 1 mg/kg bolus followed by injections of 0.8 mg/kg per day. CRP was determined on day 3. In all patients, if CRP levels did not normalize by day 3, the dose given was doubled for the remaining 12 days of treatment, whatever the initial dose.

Study criteria

The end point of this dose escalation study was the determination of the toxicity of anti–IL-6 antibody administration and its efficacy against BLPD, as assessed 4 months after treatment. We evaluated the toxicity of BE-8 in patients using the World Heath Organization Toxicity Criteria. Blood pressure, temperature, and heart rate were monitored every 10 minutes during BE-8 infusion, then every hour for 3 hours and every 3 hours until the next injection. Hematologic, renal, and liver function tests were conducted every day during treatment and on days 22, 30, 60, and 120.

Clinical symptoms of BLPD were monitored (examination of all affected sites, fever) every day during treatment, then once per week for 2 weeks, and then once per month for 6 months. Tumor size was determined by radiologic imaging (computed tomography and/or magnetic resonance imaging and/or ultrasound imaging) on days 15, 30, and 120. Biologic variables were also studied. CRP was determined every 3 days during treatment, then once per week for 2 weeks, and then on days 60 and 120. PCR tests for the detection of EBV-DNA in blood and determinations of serum immunoglobulin levels, monoclonal immunoglobulin components, and specific antibodies against EBV were carried out every 2 weeks for 1 month and then on days 60 and 120.

Complete remission (CR) was defined as the complete clinical and radiologic disappearance of tumors at all sites, the disappearance of associated biologic signs (high levels of CRP, detection of circulating B cells expressing the EBV genome), and the absence of newly involved sites. Partial remission (PR) was defined as at least a 50% decrease in measurable tumor localization, with the disappearance of fever and no newly involved sites. Stable disease (SD) was defined as no significant change in tumor measurements and no newly involved sites. Progressive disease (PD) was defined as an increase in the size of tumor lesions or the appearance of new lesions.

Immunologic investigations

The following B- and T-cell–specific mAbs were used, as previously described,31 to characterize T and B lymphocytes in blood and in organ tissue samples when available: anti-immunoglobulin heavy-chain and light-chain isotypes30; anti-CD19, CD20, CD24, CD21, and CD23 antibodies (Immunotech, Marseilles, France); and anti-CD3, CD4, and CD8 antibodies (BD, San Diego, CA). Analyses were performed by indirect immunofluorescence cytofluorometry. Fresh cells were used for membrane immunofluorescence analysis and fixed cells for intracytoplasmic staining. Immunoperoxidase staining of biopsy sections was performed as previously described.52 Serum immunoglobulin levels were determined by nephelometry, and monoclonal immunoglobulin components were determined by immunofixation.53 Serum IL-6 levels were determined using a specific anti–IL-6 enzyme-linked immunosorbent assay (ELISA) assay (CLB, Amsterdam, The Netherlands), as previously described.48 

Virologic investigations

EBV-DNA was detected in frozen material by Southern blot analysis using a randomly primed 32P-labeled probe specific for the BamHI W internal repeats of the virus, in situ hybridization with EBV-specific probes,54 PCR analysis,55 or any combination thereof. Specific antibodies (IgG and IgM isotypes) against EBV (viral capsid antigen, early antigen, EBV nuclear antigen) in organ transplant recipients were detected by an ELISA assay. Immunoperoxidase staining of biopsy sections was also performed for LMP1.52 

Clonality studies

Immunoglobulin gene rearrangement studies of proliferative B cells were performed by Southern blotting, using a probe for the sequence encoding the heavy-chain joining region (JH). BLPD was considered to be monoclonal if a single immunoglobulin rearrangement was obtained for the abnormal specimen analyzed, regardless of whether a single monoclonal serum component had been detected by immunofixation. BLPD was considered to be oligoclonal if no unique immunoglobulin heavy-chain rearrangement was observed, several serum monoclonal immunoglobulin components were detected through immunofixation, or both.

Results

Patients and BLPD characteristics

Median age at the onset of BLPD was 35 years (range, 1 year to 62 years). Organs transplanted were lung (n = 5), kidney (n = 3), liver (n = 3), and heart (n = 1). The characteristics of the BLPD are shown in Table 1. In all patients, biopsy of BLPD lesions was performed to confirm the B-lymphocyte phenotype of infiltrating cells and the presence of EBV (Table1).

Table 1.

Patients and BLPD characteristics

Patient/sex Age (y) Disease Transplant Affected sites General manifestations Pathologic morphology of BLPD lesions Phenotype of infiltrating cells in BLPD lesions Clonality of BLPD lesions EBV in BLPD lesions Detection of EBV genome by PCR out of tumor site Circulating B cells (CD19 or CD20/μl) 
1/F 41 Lymphoangiomatosis Unipulmonary Endobronchial None Polymorphic necrosis CD20+ Polyclonal LMP1+
EBER+ 
ND 80 
2/M 61 OLD Bipulmonary Bone, bone marrow, pleura, mediastinal nodes Fever,
high CRP level 
Monomorphic, plasmacytoid IgAκ+ Polyclonal EBER+ ND ND* 
3/M 33 Renal artery trauma Kidney Lymph nodes, liver Fever,
high CRP level 
Polymorphic CD20+
CD79+
CD30+ 
ND LMP1+ Blood 
4/F 27 Pulmonary hypertension Bipulmonary Oral None Monomorphic necrosis CD30+ Monoclonal LMP1+
EBER+ 
ND 20 
5/M 38 Cystic fibrosis Bipulmonary Lungs None Polymorphic necrosis CD20+
CD79+ 
ND LMP1+
EBER+ 
Blood bone marrow CSF 92  
6/M 62 Liver cirrhosis Liver Liver hilum High CRP level Polymorphic necrosis CD20+
CD79+ 
Polyclonal LMP1+ Blood 14 
7/M 49 NOCM Heart Perinephritis, cutaneous High CRP level Monomorphic plasmacytoid κ chain+ Monoclonal Southern+
PCR+ 
ND ND* 
8/M Biliary atresia Liver Liver, spleen, lymph nodes pleura Fever,
high CRP level 
Polymorphic CD20+ Monoclonal PCR+ Blood, CSF, 40  
9/M 12 α1Anti-trypsine deficiency Liver Liver hilum, graft (liver), bone marrow Fever,
high CRP level 
Polymorphic necrosis CD19+
CD20+
CD22+ 
Monoclonal EBER+
PCR+ 
Pleursy blood, bone marrow 45  
10/M 31 Interstitial nephritis Kidney Liver, abdomen, lymph nodes, subcutaneous High CRP level Polymorphic CD20+
CD79+ 
ND LMP1+ Blood ND 
11/M 32 Kidney hypoplasia Kidney Graft (kidney), kidney hilum, lymph nodes Fever,
high CRP level 
Polymorphic CD20+ ND LMP1+
EBER+ 
ND 
12/M 20 Cystic fibrosis Bipulmonary Lungs, mediastinal nodes High CRP level Polymorphic necrosis CD19+
CD20+
CD79+ 
Monoclonal LMP1+
EBER+ 
Blood None 
Patient/sex Age (y) Disease Transplant Affected sites General manifestations Pathologic morphology of BLPD lesions Phenotype of infiltrating cells in BLPD lesions Clonality of BLPD lesions EBV in BLPD lesions Detection of EBV genome by PCR out of tumor site Circulating B cells (CD19 or CD20/μl) 
1/F 41 Lymphoangiomatosis Unipulmonary Endobronchial None Polymorphic necrosis CD20+ Polyclonal LMP1+
EBER+ 
ND 80 
2/M 61 OLD Bipulmonary Bone, bone marrow, pleura, mediastinal nodes Fever,
high CRP level 
Monomorphic, plasmacytoid IgAκ+ Polyclonal EBER+ ND ND* 
3/M 33 Renal artery trauma Kidney Lymph nodes, liver Fever,
high CRP level 
Polymorphic CD20+
CD79+
CD30+ 
ND LMP1+ Blood 
4/F 27 Pulmonary hypertension Bipulmonary Oral None Monomorphic necrosis CD30+ Monoclonal LMP1+
EBER+ 
ND 20 
5/M 38 Cystic fibrosis Bipulmonary Lungs None Polymorphic necrosis CD20+
CD79+ 
ND LMP1+
EBER+ 
Blood bone marrow CSF 92  
6/M 62 Liver cirrhosis Liver Liver hilum High CRP level Polymorphic necrosis CD20+
CD79+ 
Polyclonal LMP1+ Blood 14 
7/M 49 NOCM Heart Perinephritis, cutaneous High CRP level Monomorphic plasmacytoid κ chain+ Monoclonal Southern+
PCR+ 
ND ND* 
8/M Biliary atresia Liver Liver, spleen, lymph nodes pleura Fever,
high CRP level 
Polymorphic CD20+ Monoclonal PCR+ Blood, CSF, 40  
9/M 12 α1Anti-trypsine deficiency Liver Liver hilum, graft (liver), bone marrow Fever,
high CRP level 
Polymorphic necrosis CD19+
CD20+
CD22+ 
Monoclonal EBER+
PCR+ 
Pleursy blood, bone marrow 45  
10/M 31 Interstitial nephritis Kidney Liver, abdomen, lymph nodes, subcutaneous High CRP level Polymorphic CD20+
CD79+ 
ND LMP1+ Blood ND 
11/M 32 Kidney hypoplasia Kidney Graft (kidney), kidney hilum, lymph nodes Fever,
high CRP level 
Polymorphic CD20+ ND LMP1+
EBER+ 
ND 
12/M 20 Cystic fibrosis Bipulmonary Lungs, mediastinal nodes High CRP level Polymorphic necrosis CD19+
CD20+
CD79+ 
Monoclonal LMP1+
EBER+ 
Blood None 

OLD, obstructive lung disease; NOCM, nonobstructive cardiomyopathy; CSF, cerebrospinal fluid.

*

In 2 patients, hyperbasophilic cells could be detected in blood.

All patients were on immunosuppressive treatment at the time of BLPD onset (Table 2). Eight patients had received highly aggressive immunosuppressive therapy because of graft rejection; in 4 patients, this occurred less than 3 months before the onset of BLPD. In all patients, immunosuppression was reduced when BLPD was diagnosed. In none of these patients did immunosuppression tapering for at least 8 days affect the BLPD lesions (ie, tumors were not reduced, as shown by appropriate imaging and clinical examination). Tapering of immunosuppression also had no effect on fever or serum CRP levels. All patients were, therefore, considered unresponsive to the tapering of immunosuppression over an 8-day period.

Table 2.

Immunosuppression tapering

Patient Treatment of last rejection episode Time from last rejection episode to BLPD onset (mo) IS at BLPD onset Reduction of IS T-cell count before anti–IL-6 (CD3/μL) Anti-EBV antibodies before treatment Anti-EBV antibodies after treatment
(day 30) 
 1 3 Pulse steroids Steroids, CsA, azathioprine Increase 33% steroids
Stop azathioprine
Reduction 50% CsA 
660 IgM VCA
IgG VCA+
IgG EBNA 
IgM VCA
IgG VCA+
IgG EBNA 
 2 Pulse steroids, ATG, OKT3 10 Steroids, CsA Reduction 50% CsA ND IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA+
IgG EBNA++ 
 3 Pulse steroids 103 Steroids, CsA, azathioprine Stop steroids
Stop azathioprine 
ND IgM VCA
IgG VCA+
IgG EBNA
IgG EA+ 
IgM VCA
IgG VCA+
IgG EBNA
IgG EA 
 4 None — Steroids, CsA, azathioprine Stop azathioprine
Reduction 50% CsA 
227 IgM VCA+
IgG VCA+++
IgG EBNA 
ND 
 5 3 Pulse steroids 1.5 Steroids, CsA, azathioprine Stop CsA
Stop azathioprine
 
1 074 IgG VCA IgG VCA 
 6 None — Steroids, FK506 Stop FK506 309 IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA+
IgG EBNA+ 
 7 ATG 11 Steroids, CsA Reduction 50% steroids
Reduction 50% CsA 
ND IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA+
IgG EBNA+ 
 8 Pulse steroids 2.5 Steroids, FK506, azathioprine Stop azathioprine
Stop FK506 
187 IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA++
IgG EBNA++ 
 9 None — Steroids, CsA Stop CsA 322 IgM VCA
IgG VCA+
IgG EBNA+++
IgG EA++ 
IgM VCA
IgG VCA++
IgG EBNA+++
IgG EA+ 
10 Pulse steroids 48 Steroids, CsA, azathioprine Stop CsA
Stop azathioprine
Reduction 50% steroids 
ND IgM VCA
IgG VCA+
IgG EBNA+IgG EA++ 
ND 
11 None — Steroids, CsA, mycophenolate Stop CsA
Reduction 50% mycophenolate 
ND IgM VCA+
IgG VCA+
IgG EBNA+ 
IgM VCA+++
IgG VCA+++
IgG EBNA+++ 
12 Pulse steroids 0.5 Steroids, CsA, azathioprine Stop CsA
Stop azathioprine 
840 IgM VCA
IgG VCA+
IgG EBNA
IgG EA+ 
IgM VCA
IgG VCA
IgG EBNA
IgG EA:ND 
Patient Treatment of last rejection episode Time from last rejection episode to BLPD onset (mo) IS at BLPD onset Reduction of IS T-cell count before anti–IL-6 (CD3/μL) Anti-EBV antibodies before treatment Anti-EBV antibodies after treatment
(day 30) 
 1 3 Pulse steroids Steroids, CsA, azathioprine Increase 33% steroids
Stop azathioprine
Reduction 50% CsA 
660 IgM VCA
IgG VCA+
IgG EBNA 
IgM VCA
IgG VCA+
IgG EBNA 
 2 Pulse steroids, ATG, OKT3 10 Steroids, CsA Reduction 50% CsA ND IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA+
IgG EBNA++ 
 3 Pulse steroids 103 Steroids, CsA, azathioprine Stop steroids
Stop azathioprine 
ND IgM VCA
IgG VCA+
IgG EBNA
IgG EA+ 
IgM VCA
IgG VCA+
IgG EBNA
IgG EA 
 4 None — Steroids, CsA, azathioprine Stop azathioprine
Reduction 50% CsA 
227 IgM VCA+
IgG VCA+++
IgG EBNA 
ND 
 5 3 Pulse steroids 1.5 Steroids, CsA, azathioprine Stop CsA
Stop azathioprine
 
1 074 IgG VCA IgG VCA 
 6 None — Steroids, FK506 Stop FK506 309 IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA+
IgG EBNA+ 
 7 ATG 11 Steroids, CsA Reduction 50% steroids
Reduction 50% CsA 
ND IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA+
IgG EBNA+ 
 8 Pulse steroids 2.5 Steroids, FK506, azathioprine Stop azathioprine
Stop FK506 
187 IgM VCA
IgG VCA+
IgG EBNA+ 
IgM VCA
IgG VCA++
IgG EBNA++ 
 9 None — Steroids, CsA Stop CsA 322 IgM VCA
IgG VCA+
IgG EBNA+++
IgG EA++ 
IgM VCA
IgG VCA++
IgG EBNA+++
IgG EA+ 
10 Pulse steroids 48 Steroids, CsA, azathioprine Stop CsA
Stop azathioprine
Reduction 50% steroids 
ND IgM VCA
IgG VCA+
IgG EBNA+IgG EA++ 
ND 
11 None — Steroids, CsA, mycophenolate Stop CsA
Reduction 50% mycophenolate 
ND IgM VCA+
IgG VCA+
IgG EBNA+ 
IgM VCA+++
IgG VCA+++
IgG EBNA+++ 
12 Pulse steroids 0.5 Steroids, CsA, azathioprine Stop CsA
Stop azathioprine 
840 IgM VCA
IgG VCA+
IgG EBNA
IgG EA+ 
IgM VCA
IgG VCA
IgG EBNA
IgG EA:ND 

IS, immunosuppression; CsA, cyclosporin A; ATG, antithymoglobulin.

One patient (patient 12) had been injected with an anti-CD20 antibody that had no effect on BLPD, 2 months before anti–IL-6 antibody treatment. In all other patients, no other treatment was performed before the initiation of anti–IL-6 mAb antibody therapy.

Treatment characteristics and tolerance

Treatment was scheduled to last 15 days. It was completed in 10 patients, and in the other 2 patients it was stopped early (on day 10 for patient 4 and on day 13 for patient 7) because of disease progression. One patient (patient 2) received a second course of anti–IL-6 antibody treatment after a relapse of BLPD. No major side effect was observed during any of the 13 courses of anti–IL-6 antibody treatment. One patient (patient 4) had moderate allergic manifestations—erythema on both hands after each anti–IL-6 antibody injection—that responded to antihistamine treatment. One patient (patient 3) had paresthesia on day 2, which then disappeared spontaneously. Two patients (patients 2, 9) had moderately high levels of arterial blood pressure, which resolved after sublingual nifedipine treatment. On day 2, patient 3 was examined for hyperkalemia associated with hyperphosphoremia and hypocalcemia, all of which resolved within 1 day. These biochemical manifestations were interpreted as a lytic syndrome.

Pharmacologic data

As high CRP concentration is known to be an in vivo hallmark of high levels of IL-6 synthesis.56-58 We assessed the effects of the treatment on CRP and IL-6 levels to determine the pharmacologic effects of the anti–IL-6 antibody. High serum CRP concentrations were found in 9 of 12 patients, and 5 of 9 patients had fever (Table 1). In all patients, CRP concentration decreased and fever disappeared after treatment, suggesting that systemic IL-6 was neutralized (Figure 1). CRP normalized within 3 days of the initiation of treatment in 7 of these 9 patients, whereas it was necessary to double the anti–IL-6 antibody dose on day 3 for 2 patients (patients 6, 11) even though the initial dose given to these patients was 0.8 mg/kg.

Fig. 1.

Evolution of CRP levels and fevers after anti–IL-6 antibody treatment.

Asterisks indicate patients in whom the absence of CRP level normalization on day 3 led to a 2-fold increase in the anti–IL-6 treatment dose.

Fig. 1.

Evolution of CRP levels and fevers after anti–IL-6 antibody treatment.

Asterisks indicate patients in whom the absence of CRP level normalization on day 3 led to a 2-fold increase in the anti–IL-6 treatment dose.

As shown in Table 3, serum IL-6 concentration was evaluated in 8 patients before treatment (after tapering immunosuppression) and was found to be elevated in 5 patients. In the 4 patients who survived for more than 2 months, IL-6 normalized or decreased significantly. Serum IL-6 concentration could not be analyzed during or immediately after treatment because of the formation of immune complexes between IL-6 and anti–IL-6 antibody that were also detected in the ELISA assay.

Table 3.

Effects of anti–IL-6 antibody treatment on BLPD

Patient Time from transplantation to BLPD onset (mo) Anti–IL-6 treatment/bolus (mg/kg) Serum IL-6 level (at day 0) (pg/mL) Serum IL-6 level 60 days after treatment (pg/mL) Effect on BLPD 4 mo after treatment General outcome Follow-up (mo) 
 1 No/0.4 < 1 CR Died (36 mo) of chronic rejection — 
 2-a3-150 84 No/0.4 < 1 < 1 PR Relapse — 
 2-b 90 No/0.4 < 1 — PD Died (7 mo) of BLPD — 
 3 108 No/0.4 ND ND CR A&W, CR 33 
 4 60 Yes/0.4 ND ND PD Anti–IL-6 antibody treatment failure A&W, CR after chemotherapy 26 
 5 Yes/0.4 < 1 CR Died (10 mo) of chronic rejection — 
 6 Yes/0.8 13 < 1 CR Died (13 mo) of liver hilum necrosis — 
 7 156 Yes/0.8 < 1 ND PD Failed anti–IL-6 antibody treatment, A&W, CR after chemotherapy 22 
 8 3.5 Yes/0.8 58 15 CR A&W, CR 21 
 9 3.5 Yes/0.8 46 < 1 PR A&W, CR after surgery and retransplantation 21 
10 84 Yes/0.8 15 — PD Died (1 mo) of BLPD — 
11 Yes/0.8 ND ND SD Anti–IL-6 antibody treatment failure, A&W, CR after surgery 19 
12 Yes/0.8 ND ND PR A&W, PR 
Patient Time from transplantation to BLPD onset (mo) Anti–IL-6 treatment/bolus (mg/kg) Serum IL-6 level (at day 0) (pg/mL) Serum IL-6 level 60 days after treatment (pg/mL) Effect on BLPD 4 mo after treatment General outcome Follow-up (mo) 
 1 No/0.4 < 1 CR Died (36 mo) of chronic rejection — 
 2-a3-150 84 No/0.4 < 1 < 1 PR Relapse — 
 2-b 90 No/0.4 < 1 — PD Died (7 mo) of BLPD — 
 3 108 No/0.4 ND ND CR A&W, CR 33 
 4 60 Yes/0.4 ND ND PD Anti–IL-6 antibody treatment failure A&W, CR after chemotherapy 26 
 5 Yes/0.4 < 1 CR Died (10 mo) of chronic rejection — 
 6 Yes/0.8 13 < 1 CR Died (13 mo) of liver hilum necrosis — 
 7 156 Yes/0.8 < 1 ND PD Failed anti–IL-6 antibody treatment, A&W, CR after chemotherapy 22 
 8 3.5 Yes/0.8 58 15 CR A&W, CR 21 
 9 3.5 Yes/0.8 46 < 1 PR A&W, CR after surgery and retransplantation 21 
10 84 Yes/0.8 15 — PD Died (1 mo) of BLPD — 
11 Yes/0.8 ND ND SD Anti–IL-6 antibody treatment failure, A&W, CR after surgery 19 
12 Yes/0.8 ND ND PR A&W, PR 

The sensitivity of ELISA test for IL-6 is 0.6 pg/mL. Levels indicated as < 1 pg/mL mean that no IL-6 could be detected by this ELISA test. When measured by this method, IL-6 levels in healthy controls were < 1 pg/mL.

ND indicates not done; A&W, alive and well.

F3-150

2-a and 2-b indicate the first and second course of anti–IL-6 antibody.

Evaluation of anti–IL-6 antibody treatment on disease outcome

Twelve patients were treated with 13 courses of anti–IL-6 antibody injection. Median follow-up time after treatment was 20 months (range, 9-33 months). CR was achieved in 5 patients (patients 1, 3, 5, 6, 8), 4 months after the initiation of treatment (Table 3). In patient 1, tumor size had decreased by 50% on day 12 of treatment, and CR was achieved on day 21. Examination of an endobronchial lesion on day 21 showed that no infiltrating tumor cells were present. Neither necrosis nor T-cell infiltration was detected. Patient 3 presented on day 2 with hyperkalemia associated with hyperphosphoremia and hypocalcemia, suggestive of a lytic syndrome. By day 3, the tumor size had decreased, and CR was achieved 5 weeks after the initiation of treatment. It was not possible to perform an examination of the lesion after CR was achieved. In patient 5, tumor size began to decrease 30 days after treatment, and CR was achieved 4 months after treatment. Examination of the lungs confirmed that infiltrating tumor cells were no longer present and that there was no necrosis, nor were there infiltrating T cells. In patient 6, tumor reduction was observed 30 days after treatment, and CR was achieved 2 months after treatment. Analysis showed that the infiltrating cells had been replaced by severe necrosis. In patient 8, pleuritis had disappeared by day 3, and CR was achieved on day 15. No pathologic examination was performed.

None of these patients had a relapse of BLPD. All can be considered cured of BLPD. However, 3 of these 5 patients died 10, 13, and 36 months after treatment because of chronic rejection in 2 patients and severe liver hilum necrosis in the other, which may be considered a sequela of BLPD. Two patients are alive and well 21 and 33 months, respectively, after anti–IL-6 antibody treatment.

Partial remission was observed in 3 patients (patients 2, 9, 12). In patient 2, pleurisy decreased by the third day after treatment, mediastinal nodes were half their size 1 month after treatment, and BLPD decreased by approximately 90% only 2 months after treatment. However, BLPD relapsed 5 months after treatment. This patient received a second course of anti–IL-6 antibody treatment, which was ineffective. This patient eventually died of progressive disease. In patient 9, a decrease in tumor size became detectable 15 days after the initiation of treatment. This PR made it possible to perform surgery and retransplantation that had not previously been feasible. Pathologic examination of the liver showed necrosis of 80% of the tumor that was infiltrated by T cells and histiocytic cells. This patient was alive and well, in complete remission, at the 21-month follow-up. In patient 12, a slight decrease in tumor size was observed by day 30. Three months later, the tumor decreased by 90%. Nine months after treatment, this patient was still in PR and had a small persistent lesion in the lung but no associated manifestations. Before the anti–IL-6 antibody treatment, this patient received a course of anti-CD20 antibody that had no effect on BLPD.

Anti–IL-6 antibody treatment was effective in 8 patients (5 in CR, 3 in PR). The reintroduction of highly aggressive immunosuppression in 3 of these patients because of episodes of rejection did not lead to BLPD relapse.

Stable disease was observed in one patient (patient 11), who was then treated with anti-CD20 antibody, which also failed to control BLPD. This patient was then treated by surgery and retransplantation and is alive and well, in complete remission, 19 months after treatment.

In 3 patients, treatment did not prevent disease progression (patients 4, 7, 10). Patient 10 died within 1 month because of disease progression, despite the use of chemotherapy. In patients 7 and 10, anti–IL-6 antibody treatment was stopped on days 10 and day 13, respectively, because of disease progression, but chemotherapy led to complete remission. These 2 patients are still alive and well and in CR 22 and 26 months, respectively, after treatment.

Anti–IL-6 antibody treatment was effective at controlling associated signs of BLPD such as high CRP concentration and fever. This treatment was also shown to be effective by PCR detection of the EBV genome in the blood and the determination of serum immunoglobulin concentration by immunofixation. For 7 patients, the EBV genome was detected in the blood before treatment. We were able to evaluate 6 of these patients after treatment. The EBV genome was no longer detectable in the blood 2 to 4 months after treatment in 5 of these 6 patients. Six of 10 patients with detectable serum monoclonal immunoglobulin components on immunofixation were evaluated after treatment. In 5 of them, the monoclonal immunoglobulin components had disappeared. Most of the survivors developed full antibody responses to EBV, including anti-EBNA antibodies (Table 2).

Analysis of factors that might have influenced disease outcome

BLPD characteristics such as clonality, EBV genome detection in blood, monoclonal immunoglobulin component, number or localization of affected sites, and time to BLPD onset and patient characteristics such as age, type of transplantation, and type of initial disease were tested as possible factors influencing outcome after anti–IL-6 antibody treatment.

The dose of anti–IL-6 antibody given (0.4 vs 0.8 mg/kg) did not affect its efficacy (Table 3). Although no firm conclusions can be drawn because of the small number of patients, time to BLPD onset seemed to be the only factor affecting treatment efficacy. Indeed, for the 7 patients in whom BLPD occurred within 6 months of transplantation, CR was achieved in 4 patients and PR was achieved in 2 patients (Table4). Conversely, for the 5 patients in whom BLPD occurred more than 5 years after BLPD, CR was achieved in only one patient and PR in another, who eventually had a relapse, whereas the disease progressed in 3.

Table 4.

Influence of time to BLPD onset on anti–IL-6 antibody treatment efficacy

Time to BLPD onset CR PR SD PD 
< 6 mo 
> 5 y 14-150 
Time to BLPD onset CR PR SD PD 
< 6 mo 
> 5 y 14-150 
F4-150

This patient had a relapse; a second cure had no effect (PD).

Discussion

In this phase 1-2 clinical trial, 12 patients with BLPD after organ transplantation were treated intravenously by daily injections of 0.4 to 0.8 mg/kg per day of a mouse monoclonal anti–IL-6 antibody (B-E8)51 for 15 days in 10 patients and for 10 and 13 days, respectively, in 2 other patients. This antibody has previously been used to treat patients with myeloma,56 B lymphoma related to EBV infection in the patients with HIV,59Castleman disease,60 and severe rheumatoid arthritis.61 In all these studies, treatment was well tolerated. The treatment was also well tolerated in this study, and no major side effects were reported for any of the doses of anti–IL-6 mAb used. These data suggest that this mAb is safe for use in therapeutic trials at doses up to 0.8 mg/kg per day for 15 days.

To determine the pharmacologic kinetics of anti–IL-6 mAb antibody, we analyzed CRP and IL-6 levels. CRP is produced by human hepatocytes in response to IL-6 stimulation58 and is known to be indicative of the presence of high levels of IL-6.56-58Nine patients had high CRP levels. The normalization of serum CRP concentration by treatment in all 9 patients suggests that IL-6 was systematically neutralized. Two of these 9 patients, both of whom received an initial anti–IL-6 antibody dose of 0.8 mg/kg, had persistently high CRP levels after 3 days of treatment. The dose of anti–IL-6 mAb was therefore increased, resulting in the normalization of CRP concentration. This suggests that CRP determination during treatment may be useful for assessing whether a pharmacologic effect has been achieved. However, CRP concentration was not predictive of treatment efficacy.

Treatment was clinically effective in 8 patients (5 in CR, 3 in PR). BLPD relapsed in only one of these 8 patients and then became insensitive to treatment. These data indicate that the anti–IL-6 mAb may be useful in the treatment of severe BLPD.

In all cases, prior immunosuppression tapering for an 8-day period had no effect on BLPD. However, one could argue that this delay is too short and that the observed remissions could be related to a delayed effect of immunosuppression reduction. This is unlikely because the observed remission rate under immunosuppression tapering is generally lower than the one observed in our series (8 of 12 patients). Moreover, this 8-day period of immunosuppression reduction has been previously proposed as an appropriate delay to allow treatment by anti–B-cell monoclonal antibodies.32 The efficacy of anti–IL-6 antibody may be similar to that of anti-B-cell mAb, as complete remission was achieved in 61% of the 58 patients with BLPD treated with anti-B mAbs.32 Anti–IL-6 mAb treatment was not effective in 4 patients (1 in SD, 3 in PD). However, for 3 of these 4 patients, improvements were achieved with another treatment (surgery in 1 patient and chemotherapy in 2 patients). Thus, the lack of efficacy of the anti–IL-6 mAb did not preclude the use of alternative therapies such as surgery and chemotherapy.

These encouraging data require confirmation in a larger group of patients, allowing statistical analysis and including patients with post-BMT BLPD, which is known to induce a poorer outcome.32 It may also be of value to perform a phase 3 clinical trial in which anti–IL-6 antibody treatment could be compared to or associated with other forms of treatment (eg, anti-CD20 [anti-B cell]) mAbs or cytotoxic T lymphocytes in patients who have undergone BMT12,29).

Clonality, type of transplantation, and sites affected did not seem to influence treatment efficacy. The only factor that seemed to have a strong effect on efficacy was time to BLPD onset. These findings require confirmation in a larger series of patients. However, similar results were reported by Benkerrou et al,32 who showed in a multivariate analysis that the late onset of BLPD was a major risk factor for the failure of anti-B-cell mAb treatment. Late-onset BLPD may be caused by a different physiopathogenic mechanism, with secondary oncogenic events (such as bcl-2 rearrangements, c-myc, n-ras, and p53 mutations) and LMP1 deletions62-65 responsible for the formation of true lymphomas. In such cases, B-cell proliferation could be insensitive to anti–B-cell or anti–IL-6 antibody treatment but responsive to chemotherapy.

Our data, which are consistent with those obtained for SCID mice injected with B-cell lines derived from patients with BLPD,48 suggest that IL-6 may, in some cases, have a major role in BLPD growth. Pathologic examination after treatment was possible in 4 patients in whom treatment was effective. In 2 patients, extensive tumor necrosis was observed. In one, infiltrating T cells and histiocytic cells replaced infiltrating B cells. In 2 other cases, complete resolution of BLPD was observed. No firm conclusions can be drawn from these data concerning the mechanism of BLPD resolution after anti–IL-6 antibody treatment. There are several possibilities. First, IL-6 may act as an autocrine–paracrine growth factor and may promote the growth of EBV-infected B cells. Indeed, IL-6 has been shown to promote the growth of EBV-infected B cells45,46 and patients with BLPD produce abnormally high levels of IL-6.45,47 A tumorigenic role for IL-6 in BLPD was also suggested by the results of experiments in which EBV-transformed B cells were transfected with human IL-6 cDNA: transfection significantly increased the proliferation of these cells in vivo and in vitro.49,50 These observations suggest that original tumor cells (EBV-infected B cells), stromal cells, or both—as suggested for myeloma,66 immunoblastic lymphoma,40 and BLPD47—synthesize IL-6 that may act directly on the target EBV-infected B cells, promoting their growth. Alternatively, IL-6 has been shown to inhibit immune effector functions, such as natural killer (NK) cell activity, and cytotoxic functions of splenocytes in athymic mice, thereby permitting tumor development.67 Therefore, NK cells, the function of which might be restored by anti–IL-6 antibody, may be involved in disease regression. However, it has been shown that beige–SCID mice, which show little NK activity, display a similar response to the anti–IL-6 antibody treatment of implanted EBV-B cell tumors (A.D. et al, unpublished data, 1997). These 2 mechanisms are not mutually exclusive and may both be involved in the potential efficacy of the anti–IL-6 monoclonal antibody.

The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked “advertisement” in accordance with 18 U.S.C. section 1734.

References

References
1
Frizzera
G
Hanto
D
Gajl-Peczalska
K
et al. 
Polymorphic diffuse B-cell hyperplasias and lymphomas in renal transplant recipients.
Cancer Res.
41
1981
4262
4279
2
Schubach
W
Hackman
R
Neiman
P
Miller
G
Thomas
E
A monoclonal immunoblastic sarcoma in donor cells bearing Epstein-Barr virus genomes following allogeneic marrow grafting for acute lymphoblastic leukemia.
Blood.
60
1982
180
187
3
Hanto
D
Najarian
J
Advances in the diagnosis and treatment of EBV-associated lymphoproliferative diseases in immunocompromised hosts.
J Surg Oncol.
30
1985
215
220
4
Nalesnik
M
Jaffe
R
Starzl
T
et al. 
The pathology of posttransplant lymphoproliferative disorders occurring in the setting of cyclosporine A-prednisone immunosuppression.
Am J Pathol.
133
1988
173
192
5
Cleary
M
Nalesnik
M
Shearer
W
Sklar
J
Clonal analysis of transplant-associated lymphoproliferations based on the structure of the genomic termini of the Epstein-Barr virus.
Blood.
72
1988
349
352
6
Katz
B
Raab-Traub
N
Miller
G
Latent and replicating forms of Epstein-Barr virus DNA in lymphomas and lymphoproliferative diseases.
J Infect Dis.
160
1989
589
598
7
d'Amore
E
Manivel
J
Gajl-Peczalska
K
et al. 
B-cell lymphoproliferative disorders after bone marrow transplant: an analysis of ten cases with emphasis on Epstein-Barr virus detection by in situ hybridization.
Cancer.
68
1991
1285
1295
8
Kieff
E
Epstein-Barr virus and its replication.
Fields Virology.
Fields
BN KD
Howley
PM
Chanock
RM
et al. 
1996
2343
Lippincott-Raven
Philadelphia
9
Rickinson A, Kieff E. Epstein-Barr virus: In: Fields BN KD, Howley PM, Chanock RM, et al, eds. Fields Virology. Philadelphia: Lippincott-Raven; 1996:2397.
10
Shearer
W
Ritz
J
Finegold
M
et al. 
Epstein-Barr virus-associated B-cell proliferations of diverse clonal origins after bone marrow transplantation in a 12-year-old patient with severe combined immunodeficiency.
N Engl J Med.
312
1985
1151
1159
11
Birx
D
Redfield
R
Tosato
G
Defective regulation of Epstein-Barr virus infection in patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related disorders.
N Engl J Med.
314
1986
874
879
12
Papadopoulos
EB
Ladanyi
M
Emanuel
D
et al. 
Infusions of donor leukocytes to treat Epstein-Barr virus-associated lymphoproliferative disorders after allogeneic bone marrow transplantation.
N Engl J Med.
330
1994
1185
1191
13
Lucas
KG
Small
TN
Heller
G
Dupont
B
O'Reilly
RJ
The development of cellular immunity to Epstein-Barr virus after allogeneic bone marrow transplantation.
Blood.
87
1996
2594
2603
14
Cen
H
Williams
P
McWilliams
H
Breinig
M
Ho
M
McKnight
J
Evidence for restricted Epstein-Barr virus latent gene expression and anti-EBNA antibody response in solid organ transplant recipients with posttransplant lymphoproliferative disorders.
Blood.
81
1993
1393
1403
15
Cohen
J
Epstein-Barr virus lymphoproliferative disease associated with acquired immunodeficiency.
Medicine.
70
1991
137
160
16
Thomas
J
Allday
M
Crawford
D
Epstein-Barr virus-associated lymphoproliferative disorders in immunocompromised individuals.
Adv Cancer Res.
57
1991
329
380
17
Curtis
RE
Travis
LB
Rowlings
PA
et al. 
Risk of lymphoproliferative disorders after bone marrow transplantation: a multi-institutional study.
Blood.
94
1999
2208
2216
18
Hale
G
Waldmann
H
Risks of developing Epstein-Barr virus-related lymphoproliferative disorders after T-cell–depleted marrow transplants: CAMPATH Users.
Blood.
91
1998
3079
3083
19
Starzl
T
Nalesnik
M
Porter
K
et al. 
Reversibility of lymphomas and lymphoproliferative lesions developing under cyclosporin-steroid therapy.
Lancet.
1
1984
583
587
20
Swinnen
L
Costanzo-Nordin
M
Fisher
S
et al. 
Increased incidence of lymphoproliferative disorders after immunosuppression with the monoclonal antibody OKT3 in cardiac-transplant recipients.
N Engl J Med.
323
1990
1723
1728
21
Langnas
A
Shaw
BJ
Antonson
D
et al. 
Preliminary experience with intestinal transplantation in infants and children.
Pediatrics.
97
1996
443
448
22
Ho
M
Jaffe
R
Miller
G
et al. 
The frequency of Epstein-Barr virus infection and associated lymphoproliferative syndrome after transplantation and its manifestations in children.
Transplantation.
45
1988
719
727
23
Fischer
A
Landais
P
Friedrich
W
et al. 
Bone marrow transplantation (BMT) in Europe for primary immunodeficiencies other than severe combined immunodeficiency: a report from the European Group for BMT and the European Group for Immunodeficiency.
Blood.
83
1994
1149
1154
24
Shapiro
R
McClain
K
Frizzera
G
et al. 
Epstein-Barr virus associated B cell lymphoproliferative disorders following bone marrow transplantation.
Blood.
71
1988
1234
1243
25
Ash
R
Casper
J
Chitambar
C
et al. 
Successful allogeneic transplantation of T-cell–depleted bone marrow from closely HLA-matched unrelated donors.
N Engl J Med.
322
1990
485
494
26
Pirsch
J
Stratta
R
Sollinger
H
et al. 
Treatment of severe Epstein-Barr virus-induced lymphoproliferative syndrome with ganciclovir: two cases after solid organ transplantation.
Am J Med.
86
1989
241
244
27
Garrett
T
Chadburn
A
Barr
M
et al. 
Posttransplantation lymphoproliferative disorders treated with cyclophosphamide–doxorubicin–vincristine–prednisone chemotherapy.
Cancer.
72
1993
2782
2785
28
Shapiro
R
Chauvenet
A
McGuire
W
et al. 
Treatment of B-cell lymphoproliferative disorders with interferon alfa and intravenous gamma globulin.
N Engl J Med.
318
1988
1334
29
Rooney
C
Smith
C
Ng
C
et al. 
Use of gene-modified virus-specific T lymphocytes to control Epstein-Barr–virus-related lymphoproliferation.
Lancet.
345
1995
9
13
30
Blanche
S
Le Deist
F
Veber
F
et al. 
Treatment of severe Epstein-Barr virus-induced polyclonal B-lymphocyte proliferation by anti-B-cell monoclonal antibodies: two cases after HLA-mismatched bone marrow transplantation.
Ann Intern Med.
108
1988
199
203
31
Fischer
A
Blanche
S
Le Bidois
J
et al. 
Anti–B-cell monoclonal antibodies in the treatment of severe B-cell lymphoproliferative syndrome following bone marrow and organ transplantation.
N Engl J Med.
324
1991
1451
1456
32
Benkerrou
M
Jais
J
Leblond
V
et al. 
Anti–B-cell monoclonal antibody treatment of severe posttransplant B-lymphoproliferative disorder: prognostic factors and long-term outcome.
Blood.
92
1998
3137
3147
33
Kuehnle
I
Huls
MH
Liu
Z
et al. 
CD20 monoclonal antibody (rituximab) for therapy of Epstein-Barr virus lymphoma after hemopoietic stem-cell transplantation.
Blood.
95
2000
1502
1505
34
Faye
A
Van Den Abeele
T
Peuchmaur
M
Mathieu-Boue
A
Vilmer
E
Anti-CD20 monoclonal antibody for post-transplant lymphoproliferative disorders [letter].
Lancet.
352
1998
1285
35
Milpied
N
Vasseur
B
Parquet
N
et al. 
Humanized anti-CD20 monoclonal antibody (rituximab) in post transplant B-lymphoproliferative disorder: a retrospective analysis on 32 patients.
Ann Oncol.
11(suppl 1)
2000
113
116
36
Van Snick
J
Interleukin-6: an overview.
Annu Rev Immunol.
8
1990
253
278
37
Hirano
T
Akira
S
Taga
T
Kishimoto
T
Biological and clinical aspects of interleukin 6.
Immunol Today.
11
1990
443
449
38
Kishimoto
T
The biology of interleukin-6.
Blood.
74
1989
1
10
39
Kishimoto
T
Akira
S
Narazaki
M
Taga
T
Interleukin-6 family of cytokines and gp130.
Blood.
86
1995
1243
1254
40
Emilie
D
Coumbaras
J
Raphael
M
et al. 
Interleukin-6 production in high-grade B lymphomas: correlation with the presence of malignant immunoblasts in acquired immunodeficiency syndrome and in human immunodeficiency virus-seronegative patients.
Blood.
80
1992
498
504
41
Akira
S
Taga
T
Kishimoto
T
Interleukin-6 in biology and medicine.
Adv Immunol.
54
1993
1
78
42
Kawano
M
Hirano
T
Matsuda
T
et al. 
Autocrine generation and requirement of BSF-2/IL-6 for human multiple myelomas.
Nature.
332
1988
83
85
43
Shimizu
S
Yoshioka
R
Hirose
Y
Sugai
S
Tachibana
J
Konda
S
Establishment of two interleukin 6 (B cell stimulatory factor 2/interferon beta 2)-dependent human bone marrow-derived myeloma cell lines.
J Exp Med.
169
1989
339
344
44
Klein
B
Zhang
X
Lu
Z
Bataille
R
Interleukin-6 in human multiple myeloma.
Blood.
85
1995
863
872
45
Tosato
G
Tanner
J
Jones
K
Revel
M
Pike
S
Identification of interleukin-6 as an autocrine growth factor for Epstein-Barr virus-immortalized B cells.
J Virol.
64
1990
3033
3041
46
Tosato
G
Seamon
K
Goldman
N
et al. 
Monocyte-derived human B-cell growth factor identified as interferon-beta 2 (BSF-2, IL-6).
Science.
239
1988
502
504
47
Tosato
G
Jones
K
Breinig
M
McWilliams
H
McKnight
J
Interleukin-6 production in posttransplant lymphoproliferative disease.
J Clin Invest.
91
1993
2806
2814
48
Durandy
A
Emilie
D
Peuchmaur
M
et al. 
Role of IL-6 in promoting growth of human EBV-induced B-cell tumors in severe combined immunodeficient mice.
J Immunol.
152
1994
5361
5367
49
Tohyama
N
Karasuyama
H
Tada
T
Growth autonomy and tumorigenicity of interleukin 6-dependent B cells transfected with interleukin 6 cDNA.
J Exp Med.
171
1990
389
400
50
Scala
G
Quinto
I
Ruocco
M
et al. 
Expression of an exogenous interleukin 6 gene in human Epstein Barr virus B cells confers growth advantage and in vivo tumorigenicity.
J Exp Med.
172
1990
61
68
51
Wijdenes
J
Clement
C
Klein
B
et al. 
Human recombinant dimeric IL-6 binds to its receptor as detected by anti–IL-6 monoclonal antibodies.
Mol Immunol.
28
1991
1183
1192
52
Jarry
A
Cerf-Bensussan
N
Brousse
N
Guy-Grand
D
Muzeau
F
Potet
F
Same peculiar subset of HML1+ lymphocytes present within normal intestinal epithelium is associated with tumoral epithelium of gastrointestinal carcinomas.
Gut.
29
1988
1632
1638
53
Fischer
A
Simon
F
Le Deist
F
Blanche
S
Griscelli
C
Fischer
A
Prospective study of the occurrence of monoclonal gammopathies following bone marrow transplantation in young children.
Transplantation.
49
1990
731
735
54
Fermand
J
Gozlan
J
Bendelac
A
Delauche-Cavallier
M
Brouet
J
Morinet
F
Detection of Epstein-Barr virus in epidermal skin lesions of an immunocompromised patient.
Ann Intern Med.
112
1990
511
515
55
Rozenberg
F
Lebon
P
Amplification and characterization of herpesvirus DNA in cerebrospinal fluid from patients with acute encephalitis.
J Clin Microbiol.
29
1991
2412
2417
56
Klein
B
Wijdenes
J
Zhang
X
et al. 
Murine anti-interleukin-6 monoclonal antibody therapy for a patient with plasma cell leukemia.
Blood.
78
1991
1198
1204
57
Brandt
S
Bodine
D
Dunbar
C
Nienhuis
A
Dysregulated interleukin-6 expression produces a syndrome resembling Castleman's disease in mice.
J Clin Invest.
86
1990
592
599
58
Heinrich
P
Castell
J
Andus
T
Interleukin-6 and the acute phase response.
Biochem J.
265
1990
621
636
59
Emilie
D
Wijdenes
J
Gisselbrecht
C
et al. 
Administration of an anti-interleukin-6 monoclonal antibody to patients with acquired immunodeficiency syndrome and lymphoma: effect on lymphoma growth and on B clinical symptoms.
Blood.
84
1994
2472
2479
60
Beck
J
Hsu
S
Wijdenes
J
et al. 
Brief report: alleviation of systemic manifestations of Castleman's disease by monoclonal anti-interleukin-6 antibody.
N Engl J Med.
330
1994
602
605
61
Wendling
D
Racadot
E
Wijdenes
J
Treatment of severe rheumatoid arthritis by anti-interleukin 6 monoclonal antibody.
J Rheumatol.
20
1993
259
262
62
Knowles
D
Cesarman
E
Chadburn
A
et al. 
Correlative morphologic and molecular genetic analysis demonstrates three distinct categories of posttransplantation lymphoproliferative disorders.
Blood.
85
1995
552
565
63
Kingma
D
Weiss
W
Jaffe
E
Kumar
S
Frekko
K
Raffeld
M
Epstein-Barr virus latent membrane protein-1 oncogene deletions: correlations with malignancy in Epstein-Barr virus–associated lymphoproliferative disorders and malignant lymphomas.
Blood.
88
1996
242
251
64
Smir
B
Hauke
R
Bierman
P
et al. 
Molecular epidemiology of deletions and mutations of the latent membrane protein 1 oncogene of the Epstein-Barr virus in posttransplant lymphoproliferative disorders.
Lab Invest.
75
1996
575
588
65
Murray
P
Swinnen
L
Constandinou
C
et al. 
BCL-2 but not its Epstein-Barr virus-encoded homologue, BHRF1, is commonly expressed in posttransplantation lymphoproliferative disorders.
Blood.
87
1996
706
711
66
Taga
T
Kawanishi
Y
Hardy
R
Hirano
T
Kishimoto
T
Receptors for B cell stimulatory factor 2: quantitation, specificity, distribution, and regulation of their expression.
J Exp Med.
166
1987
967
981
67
Tanner
J
Tosato
G
Impairment of natural killer functions by interleukin-6 increases lymphoblastoid cell tumorigenicity in athymic mice.
J Clin Invest.
88
1991
239
247

Author notes

Elie Haddad, Service de Nephrologie Pediatrique, 48 Blvd Serrurier, 75019 Paris, France; e-mail:elie.haddad@rdb.ap-hop-paris.fr.