Abstract

Seventeen patients transplanted with hematopoietic cells to correct severe T lymphocyte immunodeficiency resulting from complete DiGeorge anomaly were identified worldwide, and retrospective data were obtained using a questionnaire-based survey. Patients were treated at a median age of 5 months (range, 2-53 months) between 1995 and 2006. Bone marrow was used in 11 procedures in 9 cases: 6 from matched unrelated donors, 4 from human leukocyte antigen (HLA)-identical siblings, and one haploidentical parent with T-cell depletion. Unmobilized peripheral blood was used in 8 cases: 5 from HLA-identical siblings, one from a matched unrelated donor, one from an HLA-identical parent, and one unrelated matched cord blood. Conditioning was used in 5 patients and graft-versus-host disease prophylaxis in 11 patients. Significant graft-versus-host disease occurred in 9 patients, becoming chronic in 3. Median length of follow-up was 13 months, with transplantation from HLA-matched sibling showing the best results. Median survival among deceased patients (10 patients) was 7 months after transplantation (range, 2-18 months). The overall survival rate was 41%, with a median follow-up of 5.8 years (range, 4-11.5 years). Among survivors, median CD3 and CD4 counts were 806 (range, 644-1224) and 348 (range, 225-782) cells/mm3, respectively, CD4+/CD45RA+ cells remained very low, whereas mitogen responses were normalized.

Introduction

The DiGeorge anomaly (DGA) results from failure of normal third and fourth pharyngeal pouch development, leading to absence or hypoplasia of the parathyroid glands, conotruncal anomalies, and thymic hypoplasia or aplasia, causing variable T lymphocyte deficiency. DGA, also known as DiGeorge syndrome, can occur as a part of several entities of which 22q11 microdeletion hemizygosity is the most common with an incidence of 1 in 3000 to 4000 live births. It is also described in other chromosomal abnormalities, including CHARGE syndrome (colobomas, heart malformations, atresia of the choanae, retarded growth and development, genital abnormalities, and ear anomalies)1  and as a complication of diabetic embryopathy.2,3  The phenotype of patients with DGA may vary widely.4  Less than 1% of patients present with complete athymia leading to a life-threatening T lymphocyte defect with a TB+NK+ severe combined immunodeficiency (SCID) phenotype (complete DiGeorge anomaly [cDGA]).4  In typical forms of cDGA, T lymphocytes are absent or present in extremely low numbers (< 50 CD3+ cells/mm3), and there is an absent or very low proliferative response to mitogens such as phytohemagglutinin. In atypical forms of cDGA, characterized by oligoclonal peripheral T lymphocyte expansion, often associated with erythroderma and lymphadenopathy, the diagnosis is based on a lack of naive T lymphocytes (< 50 CD3+CD45RA+CD62L+ cells/mm3), indicating absence of recent thymic emigrants.5 

Patients with cDGA present a therapeutic challenge. In contrast to patients with other forms of SCID, the absence of T lymphocytes is the result of a lack of thymic environment rather than an intrinsic hematopoietic defect.6  Thus, patients treated with bone marrow transplantation can achieve peripheral engraftment of post-thymic donor T lymphocytes but do not demonstrate ongoing T-cell lymphopoiesis. Adoptive transfer of cells of hematopoietic origin, achieving long-term survival of the patient, has been published in a few case reports only, including the use of bone marrow in 5 patients,7-11  cord blood in one,12  and peripheral blood lymphocyte (PBL) infusion in 4.13-16 

Reports of the use of thymus transplantation in athymic infants has shown very promising results initially using fetal tissue17,18  and more recently postnatal infant thymuses.1,19  As the current literature reports only individual cases and publication bias was suspected, we performed a retrospective, worldwide, questionnaire-based survey on outcome of cDGA patients transplanted with cells of hematopoietic origin.

Methods

Data collection

Centers in Europe known to have performed hematopoietic cell transplantation (HCT) for T lymphocyte deficiency in patients with cDGA were identified through the Stem Cell Transplantation for Immunodeficiencies in Europe registry in Paris; other centers were contacted based on a literature search of published case reports and through personal communication. Data from a detailed survey questionnaire were obtained on 17 patients transplanted in 10 centers in 4 European countries, Canada, Japan, and the United States, between 1995 and 2006 with follow-up between 2 months and 12 years (median, 13 months). Partial data from 9 of these 17 patients have been previously published in individual reports.6,8,10,11,14-16,20 

Patient characteristics

Characteristics of the 17 patients based on data from the questionnaires are shown in Table 1. All had features consistent with cDGA (TB+NK+ SCID phenotype). Absence of thymus was demonstrated by chest radiograph (patients 4, 7, and 16), nuclear magnetic resonance imaging (patient 13), ultrasound (patient 9), or by direct inspection at surgery (patients 5 and 8). More than one method was used for some patients. At presentation, the T lymphocytes were absent (< 50 CD3+ cells/mm3) in 14 patients; in 3 (patients 9, 11, and 16), 142, 70, and 150 T lymphocytes/mm3, respectively, were detected, but no cells of naive (CD45RA+) phenotype. More specific markers for recent thymic emigrants (T lymphocyte receptor excision circles [TRECs] or CD45RA+/CD62L+) were missing in all 3 of the patients tested (patients 6-8). Maternofetal engraftment was not detected in any of the cases. Lymphocyte proliferative response to phytohemagglutinin (PHA) was absent where tested (patients 3, 5-15, and 17). In 8 patients (patients 3, 9, 10, and 13-17) pretransplantation expansion of T lymphocytes was documented; in the 3 patients studied (patients 9, 10, and 14), oligoclonality of T lymphocytes was demonstrated through T-cell receptor-β chain family analysis. Omenn syndrome–like symptoms consistent with atypical cDGA5,6  occurred in 3 cases (patients 9, 11, and 14). A high titer of antithyroid autoantibodies was present in one case (patient 11). Males predominated in the cohort (82%); 8 patients were hemizygous for deletion at 22q11.2 locus. Seven patients had a phenotype consistent with CHARGE syndrome; in 5 of 6 tested, a mutation in CHD7 was found. In one patient, the molecular defect has unclear significance as it is outside the normal genetic region affected in CHARGE syndrome and the mother has the same genotype with no clinical correlate.

Table 1

Patient characteristics (n = 17)

Case no. Sex Country Dysmorphic face Cardiac anatomy Other anomalies Detection method of thymus absence CD3+/mm Hypopara-thyroidism CHARGE association Molecular defect (del22q11.2/CHD7) Infections before transplantation Reference 
Male Germany Present Normal Renal, genital, PMR CXR, US Present None Present/ND None 16  
Male Canada None ToF with intra-auricular defect None Surgery, CXR, CT Present None Present/ND None  
Male Japan Present ToF, absence of pulmonary valve Cleft palate, tracheobronchomalacia, atopic dermatitis-like skin eruptions Surgery, CXR, CT, US 4-107 Present None Present/ND Sepsis, 2 aseptic meningitis, and echovirus in urine 8  
Male France Present ToF GER, facial nerve palsy CXR Present None Present/ND Severe CMV infection, pneumonitis  
Male United Kingdom Present AVSD Cryptorchidism, micropenis, Dandy-Walker malformation Surgery 17 None None None/none Pneumonia (Pseudomonas spp), gastroenteritis (rotavirus)  
Female United Kingdom Present VSD, ASD, PDA Unilateral coloboma, hemivertebrae Surgery, CXR Present Present None/present None 6 (patient 1) 
Male United Kingdom Present PDA Bilateral coloboma and choanal atresia, GER, tracheoesophageal fistula, micropenis CXR NA Present None/present Pneumonitis, chronic lung disease 6 (patient 2) 
Female United Kingdom Present ToF Bilateral coloboma, Dandy-Walker malformation Surgery Present Present None/present* None  
Male United Kingdom Present ASD, PDA, left pulmonary vein stenosis Dandy-Walker malformation, unilateral coloboma, absent left tibia, bilateral talipes, right preaxial polydactyly, bilateral cryptorchidism, micropenis, macular rash on the upper trunk, hepatomegaly US 142-200† (93% DR+, only CD4+Present Present None/present None 6 (patient 3) 
10 Male France Present Normal Renal CXR, US 0-970† Present None Present/ND None  
11 Male France Present Normal Microencephaly, thyroiditis, velopharyngeal insufficiency, eczema with elevated IgE, GER, PMR, autoimmune thyroiditis, severe growth failure CXR, US 70 Present None Present/ND Sepsis and severe infections: sinusitis, pneumonias (C albicans, S aureus, P aeruginosa, S pneumoniae), CMV enteritis 14, 15  
12 Male Czech Republic Present PDA, right-sided aortal arch, FOA Bilateral retinal coloboma and choanal atresia, esophageal atresia with tracheobronchial fistula, tracheobronchomalacia, GER, genital anomalies, breath-holding attacks, PMR Surgery, MRI Present Present None/ND Sepsis (multiple organisms) 10  
13 Male United Kingdom Present PDA, FOA Bilateral coloboma, cleft palate, tracheobronchomalacia, absence of cerebellar vermis and cerebellar hypoplasia MRI 0-130 None Present None‡/ND Severe infection (parainfluenza, Pseudomonas spp)  
14 Female France None Normal Maternal diabetes, PMR, erythrodermia CXR, US 0-1830† Present None None‡/ND None  
15 Male USA Present Aberrant left subclavian artery Unilateral choanal atresia, GER, VUR (grade 5), tracheobronchomalacia, gothic web, ankyloglossia, microgastria, vertical talus, scoliosis, 2-3 toe syndactyly, Coombs-positive hemolytic anemia CXR, CT 4-85 Present Present None/present E faecium urinary tract infection 20  
16 Male Canada Present Normal Growth retardation, GER, PMR CXR 150-250 Present None Present/ND Severe bronchopneumonia (parainfluenza), recurrent thrush 11  
17 Male USA Present ToF Renal Surgery, CXR 0-224 Present None Present/ND Severe sepsis (B cereus, Enterobacter spp, R equi 
Case no. Sex Country Dysmorphic face Cardiac anatomy Other anomalies Detection method of thymus absence CD3+/mm Hypopara-thyroidism CHARGE association Molecular defect (del22q11.2/CHD7) Infections before transplantation Reference 
Male Germany Present Normal Renal, genital, PMR CXR, US Present None Present/ND None 16  
Male Canada None ToF with intra-auricular defect None Surgery, CXR, CT Present None Present/ND None  
Male Japan Present ToF, absence of pulmonary valve Cleft palate, tracheobronchomalacia, atopic dermatitis-like skin eruptions Surgery, CXR, CT, US 4-107 Present None Present/ND Sepsis, 2 aseptic meningitis, and echovirus in urine 8  
Male France Present ToF GER, facial nerve palsy CXR Present None Present/ND Severe CMV infection, pneumonitis  
Male United Kingdom Present AVSD Cryptorchidism, micropenis, Dandy-Walker malformation Surgery 17 None None None/none Pneumonia (Pseudomonas spp), gastroenteritis (rotavirus)  
Female United Kingdom Present VSD, ASD, PDA Unilateral coloboma, hemivertebrae Surgery, CXR Present Present None/present None 6 (patient 1) 
Male United Kingdom Present PDA Bilateral coloboma and choanal atresia, GER, tracheoesophageal fistula, micropenis CXR NA Present None/present Pneumonitis, chronic lung disease 6 (patient 2) 
Female United Kingdom Present ToF Bilateral coloboma, Dandy-Walker malformation Surgery Present Present None/present* None  
Male United Kingdom Present ASD, PDA, left pulmonary vein stenosis Dandy-Walker malformation, unilateral coloboma, absent left tibia, bilateral talipes, right preaxial polydactyly, bilateral cryptorchidism, micropenis, macular rash on the upper trunk, hepatomegaly US 142-200† (93% DR+, only CD4+Present Present None/present None 6 (patient 3) 
10 Male France Present Normal Renal CXR, US 0-970† Present None Present/ND None  
11 Male France Present Normal Microencephaly, thyroiditis, velopharyngeal insufficiency, eczema with elevated IgE, GER, PMR, autoimmune thyroiditis, severe growth failure CXR, US 70 Present None Present/ND Sepsis and severe infections: sinusitis, pneumonias (C albicans, S aureus, P aeruginosa, S pneumoniae), CMV enteritis 14, 15  
12 Male Czech Republic Present PDA, right-sided aortal arch, FOA Bilateral retinal coloboma and choanal atresia, esophageal atresia with tracheobronchial fistula, tracheobronchomalacia, GER, genital anomalies, breath-holding attacks, PMR Surgery, MRI Present Present None/ND Sepsis (multiple organisms) 10  
13 Male United Kingdom Present PDA, FOA Bilateral coloboma, cleft palate, tracheobronchomalacia, absence of cerebellar vermis and cerebellar hypoplasia MRI 0-130 None Present None‡/ND Severe infection (parainfluenza, Pseudomonas spp)  
14 Female France None Normal Maternal diabetes, PMR, erythrodermia CXR, US 0-1830† Present None None‡/ND None  
15 Male USA Present Aberrant left subclavian artery Unilateral choanal atresia, GER, VUR (grade 5), tracheobronchomalacia, gothic web, ankyloglossia, microgastria, vertical talus, scoliosis, 2-3 toe syndactyly, Coombs-positive hemolytic anemia CXR, CT 4-85 Present Present None/present E faecium urinary tract infection 20  
16 Male Canada Present Normal Growth retardation, GER, PMR CXR 150-250 Present None Present/ND Severe bronchopneumonia (parainfluenza), recurrent thrush 11  
17 Male USA Present ToF Renal Surgery, CXR 0-224 Present None Present/ND Severe sepsis (B cereus, Enterobacter spp, R equi 

ToF indicates tetralogy of Fallot; AVSD, atrioventricular septal defect; VSD, ventricular septal defect; ASD, atrial septal defect; PDA, patent ductus arteriosus; FOA, foramen ovale apertum; PMR, psychomotor retardation; GER, gastroesophageal reflux; VUR, vesicoureteral reflux; CXR, chest x-ray; US, ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; NA, not available; and ND, not done.

*

The mutation found is outside the typical region; the mother of the child bears the same mutation with no clinical correlate.

Autologous expansion of T cells.

Deletion at 10p excluded.

In the pretransplantation period, 10 patients had significant infections resulting from Pseudomonas spp. (4), Bacillus cereus (1), Enterobacter spp. (1), Enterococcus faecium (1), Rhodococcus equi (1), Stenotrophomonas maltophilia (1), Acinetobacter (1), echovirus (1), cytomegalovirus (CMV; 2), rotavirus (1), parainfluenza (2), and Candida (2). Some patients experienced infection with more than one organism. Infection with Pneumocystis jiroveci was not reported.

Transplantation

Donor and recipient human leukocyte antigen (HLA) matching was determined by serology and/or molecular analysis. Serologic methods were used for the earlier patients and low-resolution class I with high-resolution class II molecular DNA typing in the more recent patients; methods were dependent on each center's practice.

Seven patients had HLA-identical sibling donors: 2 received unmanipulated marrow and 5 PBL. Seven patients received grafts from unrelated donors (6 bone marrow, one PBL) of which 6 were full (10 of 10) matches and one was mismatched at the HLA-B locus. Two patients received phenotypically matched parental hematopoietic stem cells, one T lymphocyte–depleted bone marrow, and one B lymphocyte–depleted PBL. Cord blood from a matched unrelated donor was used in one patient.

Transplantation data are outlined (Table 2). Median age at transplantation was 5 months (range, 2-53 months). Four patients received serotherapy resulting from the presence of residual T lymphocytes: alemtuzumab (2), rabbit antithymocyte globulin (one), and anti-CD3 (one). One patient received fludarabine, and the remainder received no pretransplantation conditioning. One patient who was retransplanted received busulfan and cyclophosphamide before the second procedure.

Table 2

Details of transplantation and outcome (n = 17)

Case no. Age at trans-plantation Donor HLA match Graft
 
Conditioning GVHD prophylaxis Complications
 
Severe infections Length of follow-up from the first trans-plantation, months Outcome 
Source CD3+, × 106/kg CD34+, × 106/kg Acute GVHD Chronic GVHD Other 
3 mo and day 35, day 63, day 91 Brother 10/10 PBL 100 None None Skin, stage I, maximum grade 1 None Transitory aregenerative anemia None 48 Alive and well 
6 mo and mo 45 Brother 10/10 PBL; marrow 0.4 0; 5 None None Liver, stage II, maximum grade 2 None Mild transient arthritis, foot cellulitis None 79 Alive and well 
13 mo and mo 6 Brother 10/10 Marrow NA NA ATG; Bu + CY CyA, MTX None None None None 12 Sudden death at home, cause unknown 
3 mo Sister 10/10 PBL 80 NA None None None None None CMV, rotavirus Died of pneumonitis (CMV) 
5 mo Unrelated, male 12/12 Marrow 160 14 None None None None None None Died of circulatory failure during cardiac surgery 
3 mo Unrelated, male 10/10 Marrow NA 500 None CyA None None None Streptococcus spp. 144 Alive, developmental delay 
6 mo Father 5/10 Marrow* 0.02 20 None CyA None None None None Died of respiratory failure 
3 mo and day 55 Unrelated, female 11/12 Marrow 91 3.8 Campath CyA Skin, stage III, maximum grade 2 None None None Died of circulatory failure 
4 mo Unrelated, male 10/10 Cord blood 77 1.8 Campath CyA, steroids Skin, stage II, maximum grade 2 None None Parainfluenza Died of pneumonitis (parainfluenza) associated with recurrent GER 
10 2 mo and ? Sister 10/10 PBL; marrow NA NA None CyA Gut, stage II, maximum grade 2 Maximum grade 2 None NA 20 Alive, retransplanted with marrow December 2006; last follow-up May 15, 2007, no details given 
11 4.5 y Sister 10/10 PBL 10 0.07 None CyA, MMF None None None None 96 Alive and well, autoimmune thyroiditis and eczema resolved after transplant 
12 6 mo and day 36 Unrelated, male 9/10 Marrow 0.2 None None; CyA Skin and liver, stage III-IV, grade 2 None Cardiopulmonary instability, capillary leak syndrome, ileus, feeding problems, breath-holding attacks EBV reactivation (rituximab) 48 Alive, developmental delay, feeding difficulties 
13 7 mo Unrelated, male 10/10 Marrow 71 8.1 None CyA, MMF Skin, stage III; liver and gut, Stage II-IV; maximum grade 4 Skin, gut, maximum grade 4 Peritonitis associated with gastrostomy tube leakage, hypertension, renal impairment EBV reactivation (rituximab), coagulase-negative Staphylococcus spp, E coli, C albicans Died of pneumonia, chronic GVHD 
14 6 mo Unrelated, male 10/10 Marrow 56 24 OKT3, steroids CyA, MTX Skin, stage II; gut, stage II; maximum grade 2 Maximum grade 2 Pneumopathy None 18 Died of hypertrophic cardiomyopathy, pneumopathy, suspected pulmonary GVHD 
15 3 mo Unrelated, male 10/10 PBL 0.5 NA Fludarabine CyA Skin, stage III, maximum grade 2 None Pulmonary VOD, chronic pleural effusions, pulmonary edema, bowel edema, anasarca, Evans syndrome B pertusis, HHV6 positivity (cleared with ganciclovir) 14 Died of acute renal failure, intractable hyperkalemia and left ventricular dysfunction after open lung biopsy 
16 5 mo Brother 10/10 Marrow NA NA None None None None None None 62 Alive and well 
17 3 mo Mother 10/10 PBL† 10 NA None None Skin, stage III-IV; lung suspected, maximum grade 2 Suspected Transient pancytopenia None 11 Died of pulmonary hemorrhage after second cardiac surgery 
Case no. Age at trans-plantation Donor HLA match Graft
 
Conditioning GVHD prophylaxis Complications
 
Severe infections Length of follow-up from the first trans-plantation, months Outcome 
Source CD3+, × 106/kg CD34+, × 106/kg Acute GVHD Chronic GVHD Other 
3 mo and day 35, day 63, day 91 Brother 10/10 PBL 100 None None Skin, stage I, maximum grade 1 None Transitory aregenerative anemia None 48 Alive and well 
6 mo and mo 45 Brother 10/10 PBL; marrow 0.4 0; 5 None None Liver, stage II, maximum grade 2 None Mild transient arthritis, foot cellulitis None 79 Alive and well 
13 mo and mo 6 Brother 10/10 Marrow NA NA ATG; Bu + CY CyA, MTX None None None None 12 Sudden death at home, cause unknown 
3 mo Sister 10/10 PBL 80 NA None None None None None CMV, rotavirus Died of pneumonitis (CMV) 
5 mo Unrelated, male 12/12 Marrow 160 14 None None None None None None Died of circulatory failure during cardiac surgery 
3 mo Unrelated, male 10/10 Marrow NA 500 None CyA None None None Streptococcus spp. 144 Alive, developmental delay 
6 mo Father 5/10 Marrow* 0.02 20 None CyA None None None None Died of respiratory failure 
3 mo and day 55 Unrelated, female 11/12 Marrow 91 3.8 Campath CyA Skin, stage III, maximum grade 2 None None None Died of circulatory failure 
4 mo Unrelated, male 10/10 Cord blood 77 1.8 Campath CyA, steroids Skin, stage II, maximum grade 2 None None Parainfluenza Died of pneumonitis (parainfluenza) associated with recurrent GER 
10 2 mo and ? Sister 10/10 PBL; marrow NA NA None CyA Gut, stage II, maximum grade 2 Maximum grade 2 None NA 20 Alive, retransplanted with marrow December 2006; last follow-up May 15, 2007, no details given 
11 4.5 y Sister 10/10 PBL 10 0.07 None CyA, MMF None None None None 96 Alive and well, autoimmune thyroiditis and eczema resolved after transplant 
12 6 mo and day 36 Unrelated, male 9/10 Marrow 0.2 None None; CyA Skin and liver, stage III-IV, grade 2 None Cardiopulmonary instability, capillary leak syndrome, ileus, feeding problems, breath-holding attacks EBV reactivation (rituximab) 48 Alive, developmental delay, feeding difficulties 
13 7 mo Unrelated, male 10/10 Marrow 71 8.1 None CyA, MMF Skin, stage III; liver and gut, Stage II-IV; maximum grade 4 Skin, gut, maximum grade 4 Peritonitis associated with gastrostomy tube leakage, hypertension, renal impairment EBV reactivation (rituximab), coagulase-negative Staphylococcus spp, E coli, C albicans Died of pneumonia, chronic GVHD 
14 6 mo Unrelated, male 10/10 Marrow 56 24 OKT3, steroids CyA, MTX Skin, stage II; gut, stage II; maximum grade 2 Maximum grade 2 Pneumopathy None 18 Died of hypertrophic cardiomyopathy, pneumopathy, suspected pulmonary GVHD 
15 3 mo Unrelated, male 10/10 PBL 0.5 NA Fludarabine CyA Skin, stage III, maximum grade 2 None Pulmonary VOD, chronic pleural effusions, pulmonary edema, bowel edema, anasarca, Evans syndrome B pertusis, HHV6 positivity (cleared with ganciclovir) 14 Died of acute renal failure, intractable hyperkalemia and left ventricular dysfunction after open lung biopsy 
16 5 mo Brother 10/10 Marrow NA NA None None None None None None 62 Alive and well 
17 3 mo Mother 10/10 PBL† 10 NA None None Skin, stage III-IV; lung suspected, maximum grade 2 Suspected Transient pancytopenia None 11 Died of pulmonary hemorrhage after second cardiac surgery 

Semicolons separate data on each transplantation; time is rounded; PBL is always unmobilized.

NA indicates data not available; ATG indicates rabbit antithymocyte globulin; Bu, busulfan; CY, cyclophosphamide; CyA, cyclosporine A; MTX, methotrexate; MMF, mycophenolate mofetil; VOD, veno-occlusive disease; CMV, cytomegalovirus; EBV, Epstein-Barr virus; HHV6, human herpesvirus 6; and GER, gastroesophageal reflux.

*

T cell–depleted marrow.

B cell–depleted PBLs.

For graft-versus-host disease (GVHD) prophylaxis, 11 patients received cyclosporin A, of whom 2 also received methotrexate and 2 mycophenolate mofetil. One patient additionally received methylprednisolone. Six patients receiving HLA-matched grafts did not receive any GVHD prophylaxis.

All patients were isolated in high-efficiency particulate air–filtered or laminar flow facilities.

Statistical analysis

The χ2 and t tests were used for statistical analysis of patients' outcome; a P value of .05 or less was considered significant. Analyses were performed using Statistica (Version 7.1, StatSoft).

Results

Engraftment and immune reconstitution

Twelve patients (patients 1, 4-6, 9, and 11-17) showed evidence of T-cell engraftment after a single procedure (Table 3). In 2 patients (patient 15 who received fludarabine conditioning and patient 17 in whom there was no conditioning), there was evidence of some additional myeloid engraftment.

Table 3

Immunologic reconstitution after transplantation (n = 17)

Case no. Age at last follow-up Engraft-ment T cells
 
B cells
 
CD3+, cells/mm3 CD4+, cells/mm3 CD8+, cells/mm3 IRI+,index Mitogen response (PHA) TREC or equivalent* Naive/memory
 
CD19+, cells/mm3 IVIg Antibody response
 
CD4+ CD45RA+, percentage of CD4+ CD4+ CD45RO+, percentage of CD4+ Tetanus Hib 
4 y 3 mo 980 430 490 0.9 normal† ND NA 68 100 No Good response ND 
7 y 1 mo Yes 45%‡ 14%‡ 31%‡ 0.5 NA ND ND ND 40%‡ No ND ND 
2 y 1 mo Yes 496 305 259 1.2 Normal ND 25 85 365 Yes ND ND 
7 mo 900 288 612 0.5 NA ND ND ND 576 Yes ND ND 
7 mo 174 NA NA NA Normal NA NA NA NA Yes ND ND 
12 y 3 mo 786 348 433 0.8 Normal NA NA NA No Good response Good response 
10 mo No  573 Yes ND ND 
8 mo 464 NA NA NA ND NA NA 590 Yes ND ND 
10 mo 504 163 293 0.6 ND NA NA 2236 Yes ND ND 
10 NA No 0§ 50% NA NA NA 1379 Yes ND ND 
11 12.5 y 644 225 419 0.5 50% NA NA 243 No Good response Good response 
12 4 y 6 mo 806 265 472 0.6 Normal 99 219 Yes Good response ND 
13 1 y 3 mo 1342 1065 276 3.9 ND ND 84 Yes ND ND 
14 2 y 868 742 56 13.3 Normal ND 95 378 Yes NA NA 
15 1 y 5 mo Yes 196 160 39 4.1 Normal NA NA 273 No ND ND 
16 5 y 7 mo 1224 782 238 3.3 77% ND 99 1786 No Good response Good response 
17 1 y 2 mo Yes 195 176 12 14.7 33% ND NA NA 422 Yes ND ND 
Case no. Age at last follow-up Engraft-ment T cells
 
B cells
 
CD3+, cells/mm3 CD4+, cells/mm3 CD8+, cells/mm3 IRI+,index Mitogen response (PHA) TREC or equivalent* Naive/memory
 
CD19+, cells/mm3 IVIg Antibody response
 
CD4+ CD45RA+, percentage of CD4+ CD4+ CD45RO+, percentage of CD4+ Tetanus Hib 
4 y 3 mo 980 430 490 0.9 normal† ND NA 68 100 No Good response ND 
7 y 1 mo Yes 45%‡ 14%‡ 31%‡ 0.5 NA ND ND ND 40%‡ No ND ND 
2 y 1 mo Yes 496 305 259 1.2 Normal ND 25 85 365 Yes ND ND 
7 mo 900 288 612 0.5 NA ND ND ND 576 Yes ND ND 
7 mo 174 NA NA NA Normal NA NA NA NA Yes ND ND 
12 y 3 mo 786 348 433 0.8 Normal NA NA NA No Good response Good response 
10 mo No  573 Yes ND ND 
8 mo 464 NA NA NA ND NA NA 590 Yes ND ND 
10 mo 504 163 293 0.6 ND NA NA 2236 Yes ND ND 
10 NA No 0§ 50% NA NA NA 1379 Yes ND ND 
11 12.5 y 644 225 419 0.5 50% NA NA 243 No Good response Good response 
12 4 y 6 mo 806 265 472 0.6 Normal 99 219 Yes Good response ND 
13 1 y 3 mo 1342 1065 276 3.9 ND ND 84 Yes ND ND 
14 2 y 868 742 56 13.3 Normal ND 95 378 Yes NA NA 
15 1 y 5 mo Yes 196 160 39 4.1 Normal NA NA 273 No ND ND 
16 5 y 7 mo 1224 782 238 3.3 77% ND 99 1786 No Good response Good response 
17 1 y 2 mo Yes 195 176 12 14.7 33% ND NA NA 422 Yes ND ND 

Data are given for the last follow-up.

IRI indicates immunoregulatory index; PHA, phytohemagglutinin; IVIg, intravenous immunoglobulin; NA, data not available; T, T cells; Hib, Haemophilus influenzae b; and ND, not done.

*

TREC equivalent = CD4+CD45RA+CD27+ or CD3+CD45RA+CD62L.

Also stimulated with anti-CD3, CD28.

No absolute cell count available.

§

Data after first transplantation; details after the second one are not available.

The remaining 5 patients (patients 2, 3, 7, 8, and 10) did not achieve T-cell engraftment after a single procedure. Patient 7 (who received a haploidentical T cell–depleted graft) continued to lack T lymphocytes and died of respiratory failure. In the remaining 4 patients, further procedures with PBL or marrow were undertaken. T-cell engraftment was achieved in 3 patients (patients 2, 3, and 8), follow-up data are lacking in patient 10. Patient 3 received busulfan and cyclophosphamide preconditioning, and full donor engraftment was achieved.

Two other patients (patients 1 and 12) received planned repeated graft infusions despite showing evidence of T-cell engraftment after the initial treatment.

The median T lymphocyte count achieved in engrafted patients was 574 cells/mm3 (range, 0-1342 cells/mm3). TRECs or their equivalents were absent in the 7 patients in whom they were sought. In a further 3 patients, absent or very low numbers of CD4+CD45RA+ T lymphocytes were documented. Patient 3 showed an increasing proportion of naive autologous T lymphocytes to a level of 25% of CD4 cells. Seven of 14 patients with data available had an inverted CD4+/CD8+ ratio (< 1.0) after transplantation. A normal lymphocyte proliferation response to phytohemagglutinin was found in all patients tested (Table 3).

Infection after transplantation

Most infectious complications were viral (Table 2), but bacterial infections were significant in some patients. Patient 13 had pneumonia and sepsis, multiple organisms were isolated, including coagulase-negative Staphylococcus spp, Escherichia coli, Candida albicans, and C parapsilosis. Patient 15 was infected with Bordetella pertussis. Patient 6 had significant infection with Streptococcus spp. No patient had fungal infection. Viral infections predating transplantation were present in 6 cases (2 CMV, 2 parainfluenza, 1 rotavirus, 1 echovirus). Only 2 of these survived in the long-term (one with CMV and one with parainfluenza), although the viruses were not always the main cause of death. One case (patient 5) developed CMV infection after transplantation with fatal outcome, 2 developed Epstein-Barr virus infection (1 survived), and 1 developed human herpesvirus 6 (died).

Adverse events

Only 2 patients experienced no significant adverse events. Patient 1 experienced transitory marrow suppression, and mild arthritis and cellulitis were seen in patient 2. Significant acute GVHD (grades 2-4) occurred in 9 patients, in 4 the condition became chronic, and in 2 it was associated with death. Circulatory instability contributed to death in 3 patients, related to cardiac surgery in 2. Patient 14 died of hypertrophic cardiomyopathy and pneumopathy associated with suspected pulmonary GVHD. Patient 15 died with biopsy-proven pulmonary veno-occlusive disease, associated with acute renal failure.

Outcome

Median follow-up was 13 months (range, 2 months to 11.5 years). Seven patients (41%) are alive and well with a median follow-up of 5 years, 10 months (range, 4-11.5 years). The 10 deaths (59%) occurred at a median of 7 months after transplantation (range, 2-18 months). In 5 patients, death was the result of cardiorespiratory failure (3 of these deaths occurred in association with cardiac or lung surgery). Two patients died of pneumopathy and chronic GVHD, and 2 of severe viral pneumonitis (CMV, parainfluenza). One patient died unexpectedly at home of unknown cause.

Comparison of survivors and nonsurvivors is shown (Table 4). Absence of conditioning and graft from matched sibling donor were the only parameters significantly associated with survival. There were no differences in incidence of severe posttransplantation infections or GVHD between patients receiving marrow or PBL.

Table 4

Association of different parameters and outcome (n = 17)

Parameter/category Outcome
 
Survivors (n = 7) Nonsurvivors (n = 10) P 
Phenotype     
    CHARGE NS 
    DGS 10 NS 
    Atypical DGS NS 
Gene defect     
    22q11.2 NS 
    CHD7 NS 
Transplantation regimen     
    GVHD prophylaxis 11 NS 
    Conditioning .026 
Donor     
    MSD .034 
    MRD NS 
    Haploidentical NS 
    MUD NS 
Graft     
    Marrow NS 
    Combined (PBL, then marrow) NS 
    PBL NS 
    Cord NS 
    B cell–depleted PBL NS 
    T cell–depleted marrow NS 
Age at transplantation     
    Less than or equal to 3 months NS 
    Median 17 4.5 NS 
Immune reconstitution     
    T cells/mm3 (median at the last follow-up) 15 806 (5 patients) 480 (10 patients) NS 
Complications     
    GVHD (grade ≥ 2) NS 
Parameter/category Outcome
 
Survivors (n = 7) Nonsurvivors (n = 10) P 
Phenotype     
    CHARGE NS 
    DGS 10 NS 
    Atypical DGS NS 
Gene defect     
    22q11.2 NS 
    CHD7 NS 
Transplantation regimen     
    GVHD prophylaxis 11 NS 
    Conditioning .026 
Donor     
    MSD .034 
    MRD NS 
    Haploidentical NS 
    MUD NS 
Graft     
    Marrow NS 
    Combined (PBL, then marrow) NS 
    PBL NS 
    Cord NS 
    B cell–depleted PBL NS 
    T cell–depleted marrow NS 
Age at transplantation     
    Less than or equal to 3 months NS 
    Median 17 4.5 NS 
Immune reconstitution     
    T cells/mm3 (median at the last follow-up) 15 806 (5 patients) 480 (10 patients) NS 
Complications     
    GVHD (grade ≥ 2) NS 

DGS indicates DiGeorge syndrome; CHD, chromodomain helicase; MRD, matched related donor; MUD, matched unrelated donor; MSD, matched sibling donor; GVHD, graft-versus-host disease; PBL, peripheral blood lymphocyte; OBL, peripheral lymphocyte; and NS, statistically not significant.

Immune reconstitution data in those long-term survivors with evaluable data (5 patients) show the median (range) number of T lymphocytes measured at last follow-up of 806 cells/mm3 (644-1224 cells/mm3) and for CD4 counts 348 cells/mm3 (225-782 cells/mm3). No difference in these numbers was seen between those receiving PBLs or marrow, although numbers are very small. All of 6 survivors tested have normal or only mildly decreased PHA responses, and one of 7 has significant numbers of naive CD4 T cells. Five of 7 survivors no longer receive replacement immunoglobulin, 5 have received vaccinations, and of these 4 responded to tetanus toxoid, 3 to Haemophilus influenzae type B antigen, and 2 to Streptococcus pneumoniae antigens. Patient 12 was shown to have a proliferative response to tetanus toxoid but remains on immunoglobulin replacement.

Discussion

The data presented here represent the largest cohort of patients with cDGA phenotype treated with HCT for severe immunodeficiency. With a further 9 patients reported in the literature7,9,12,13,21,22  (supplemental Table 1, available on the Blood Web site; see the Supplemental Materials link at the top of the online article), details of 26 transplanted patients are available.

The overall survival (Figure 1) in the survey cohort was 41% with median follow-up of almost 6 years. If the previously published patients are also included, the survival increases to 50% with median follow-up of 8.5 years (range, 4-24 years). This mortality rate is probably skewed by the fact that infants with DGA have multisystem problems associated with the underlying disorder; 5 patients died of such complications, generally associated with cardiorespiratory failure. Four patients died of complications related to GVHD or engraftment pneumonitis (15%), 2 patients died of severe infection, and in 2 patients the cause of death is unknown. The incidence of GVHD was similar to other published series of HCT for SCID23,24 ; 6 of 17 (35%) in this series had acute GVHD of gut, liver, or lung grade 2 to 4, and a further 2 had grade 2 skin acute GVHD. Fifteen percent had chronic GVHD. However, there is an impression that GVHD in cDGA patients is more severe, or chronic than expected, given that most have had no chemotherapeutic cytoreduction before transplantation, and that the majority of donors are well matched. There are a number of possible reasons for this. First, the underlying condition may predispose to chronically inflamed tissue acting as a substrate for GVHD, for instance, lung inflammation secondary to gastroesophageal reflux and pulmonary aspiration. Second, an absence of thymus-derived regulatory T cells may predispose to prolonged and severe GVHD. Third, the reaction could be related to homeostatic expansion of donor T cells as no new T lymphopoiesis takes place in complete athymic DGA or CHARGE syndrome. Given this increased risk of severe or chronic GVHD, all patients should receive appropriate prophylaxis, including those with HLA-identical matches, and this should be cautiously discontinued, as preexisting inflammation resolves.

Figure 1

Overall survival (n = 17).

Figure 1

Overall survival (n = 17).

The failure of new lymphopoiesis may also explain the poor outcome of patients presenting with preexisting viral infection, with only 2 of 6 surviving, compared with an overall survival of 59% for patients with severe combined immunodeficiency, even after haplo-identical transplantation, in the European series.25  Given that there will be no thymopoiesis and that B lymphocytes from DiGeorge/CHARGE patients have potentially normal function, there is no advantage to engraftment of stem cell progenitors, and so conditioning is not necessary in the majority of cases; indeed, conditioning was associated with a significantly higher mortality in this series. The exceptions may be those patients with atypical cDGA or maternal T lymphocyte engraftment, in whom some form of anti-T lymphocyte serotherapy may be required before transplantation.

Although the use of marrow or PBL as source of T cells did not affect the outcome, use of PBL is more rational as adoptive transfer of mature T cells is the key principle of this procedure. Certainly, administration of T cell–depleted marrow should be strongly discouraged. On the other hand, use of matched sibling donor transplantations had a significantly better outcome than unrelated donor and cord blood transplantations. In the combined survey/published data, survival after unrelated donor PBL or marrow transplantations was only 3 of 9 and for unrelated donor cord blood was 1 of 3. Combining survey data on matched sibling donors with the literature gives an overall survival of 8 of 13 (62%). Because immune reconstitution in this condition depends on engraftment of long-lived postthymic memory T cells the choice of cord blood may not be ideal because of the antigenic naivete of the donor.

Most patients who survived long-term remain clinically well/stable without frequent infections, although 2 in the literature survey were reported as having recurrent severe infections (patients 19 and 26).9,21,22  Humoral immune function in survivors is good, with only 2 of 7 of the survivors in the survey group requiring immunoglobulin treatment (data not available from the literature group) and good antibody responses to protein or conjugate vaccines when tested. No data were available on polysaccharide antibody responses. Information on T cell-mediated immune function was not complete; where tested, there were relatively low numbers of CD3+ and CD4+ cells in most cases, an absence of naive T cells, and skewed T lymphocyte receptor repertoire. Long-term follow-up data from a recent large series of patients with other forms of SCID who have undergone HCT suggest that patients with low CD4 counts (present in all but one of the evaluable survivors in the present series) but not naive CD4 cells were significantly more probable to have complications, including infections, autoimmune inflammatory complications, and nutritional problems, than those with normal counts.26  This suggests that these patients may remain at risk of late complications, particularly if cell numbers decline with time.

One patient who had late unexplained death (patient 3) did produce significant numbers of CD4+CD45RA+ cells. It is not clear whether these were true thymic emigrants as neither TRECs analysis nor CD45RA/CD62L analysis was available. If these were true thymic emigrants, then it suggests that the patient did not have a truly complete form of DGA as suggested by the authors in a published report of this case.8 

Recent experience of transplantation of cultured thymic epithelium in patients with cDGA has shown promising results, with good immune reconstitution, including normal T-cell receptor repertoire diversity and the ongoing presence of recent thymic emigrants.2  GVHD was not seen. Survival with a median follow-up period of 3 years and 10 months was 75%. Most deaths were associated with chronic lung disease or viral infections, both predating the transplantation. Approximately one-third of the survivors developed autoimmune disease, mostly affecting the thyroid gland. It has been pointed out that patient selection in this study meant that those patients with the most severe comorbidities were not offered the therapy.17  Nevertheless, the results compare favorably with the outcome from our survey both in terms of survival and quality of immune reconstitution. Currently, thymic transplantation requires specialized facilities for thymus culture and is only available in 2 centers in the world, thus limiting its availability.

Although the data collected in this retrospective study are incomplete, and the numbers of cases in subcategories small, some tentative conclusions can be drawn. Where a well-matched sibling donor is available, infusion of peripheral lymphocytes can be considered without preconditioning, and early before end-stage organ damage occurs or worsens. Prophylactic GVHD treatment should be given, and cautiously withdrawn as any preexisting inflammation resolves. However, in a relatively well child without any infections, the survival after thymic transplantation is at least as good (75% vs 62%, although the patients were preselected) and immune reconstitution superior. Thus, for other patients, the feasibility of thymic transplantation should be considered.

The online version of this article contains a data supplement.

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 USC section 1734.

Acknowledgments

The authors thank Prof Louise Markert for invaluable help in identifying some patients and the patients and their parents for allowing us to care for them as well as learn from them.

This work was supported in part by the Czech Ministry of Education (grant VZ MSM CR 21620812) and the Czech Ministry of Health (grant MZOFNM2005).

Authorship

Contribution: A.J. and A.R.G. designed the study, prepared and collected data through a questionnaire, analyzed data, and wrote the paper; M.A.S. and E.G.D. reported on their patients and significantly contributed to the data analysis and the final version of the paper; and P.S., M.H., W.F., M.C., T.M., A.F., B.N., A.C., D.B., P.B., D.L., W.S., N.J. and F.A.B. collected data and participated in the manuscript's preparation.

Conflict-of-interest disclosure: The authors declare no competing financial interests.

Correspondence: Ales Janda, Department of Pediatric Hematology and Oncology, University Hospital Motol and 2nd Medical School, Charles University, Prague, Czech Republic; e-mail: ales.janda@lfmotol.cuni.cz.

References

References
1
Markert
ML
Devlin
BH
Alexieff
MJ
, et al. 
Review of 54 patients with complete DiGeorge anomaly enrolled in protocols for thymus transplantation: outcome of 44 consecutive transplants.
Blood
2007
, vol. 
109
 
10
(pg. 
4539
-
4547
)
2
Gosseye
S
Golaire
MC
Verellen
G
Van Lierde
M
Claus
D
Association of bilateral renal agenesis and Di George syndrome in an infant of a diabetic mother.
Helv Paediatr Acta
1982
, vol. 
37
 
5
(pg. 
471
-
474
)
3
Wang
R
Martinez-Frias
ML
Graham
JM
Jr
Infants of diabetic mothers are at increased risk for the oculo-auriculo-vertebral sequence: a case-based and case-control approach.
J Pediatr
2002
, vol. 
141
 
5
(pg. 
611
-
617
)
4
Oskarsdottir
S
Persson
C
Eriksson
BO
Fasth
A
Presenting phenotype in 100 children with the 22q11 deletion syndrome.
Eur J Pediatr
2005
, vol. 
164
 
3
(pg. 
146
-
153
)
5
Markert
ML
Alexieff
MJ
Li
J
, et al. 
Complete DiGeorge syndrome: development of rash, lymphadenopathy, and oligoclonal T cells in 5 cases.
J Allergy Clin Immunol
2004
, vol. 
113
 
4
(pg. 
734
-
741
)
6
Gennery
AR
Slatter
MA
Rice
J
, et al. 
Mutations in CHD7 in patients with CHARGE syndrome cause T-B + natural killer cell + severe combined immune deficiency and may cause Omenn-like syndrome.
Clin Exp Immunol
2008
, vol. 
153
 
1
(pg. 
75
-
80
)
7
Borzy
MS
Ridgway
D
Noya
FJ
Shearer
WT
Successful bone marrow transplantation with split lymphoid chimerism in DiGeorge syndrome.
J Clin Immunol
1989
, vol. 
9
 
5
(pg. 
386
-
392
)
8
Matsumoto
T
Amamoto
N
Kondoh
T
Nakayama
M
Takayanagi
T
Tsuji
Y
Complete-type DiGeorge syndrome treated by bone marrow transplantation.
Bone Marrow Transplant
1998
, vol. 
22
 
9
(pg. 
927
-
930
)
9
Goldsobel
AB
Haas
A
Stiehm
ER
Bone marrow transplantation in DiGeorge syndrome.
J Pediatr
1987
, vol. 
111
 
1
(pg. 
40
-
44
)
10
Janda
A
Sedlacek
P
Mejstrikova
E
, et al. 
Unrelated partially matched lymphocyte infusions in a patient with complete DiGeorge/CHARGE syndrome.
Pediatr Transplant
2007
, vol. 
11
 
4
(pg. 
441
-
447
)
11
Al-Tamemi
S
Mazer
B
Mitchell
D
, et al. 
Complete DiGeorge anomaly in the absence of neonatal hypocalcemia and velofacial and cardiac defects.
Pediatrics
2005
, vol. 
116
 
3
(pg. 
e457
-
e460
)
12
Ohtsuka
Y
Shimizu
T
Nishizawa
K
, et al. 
Successful engraftment and decrease of cytomegalovirus load after cord blood stem cell transplantation in a patient with DiGeorge syndrome.
Eur J Pediatr
2004
, vol. 
163
 
12
(pg. 
747
-
748
)
13
Bowers
DC
Lederman
HM
Sicherer
SH
Winkelstein
JA
Chen
AR
Immune constitution of complete DiGeorge anomaly by transplantation of unmobilised blood mononuclear cells.
Lancet
1998
, vol. 
352
 
9145
(pg. 
1983
-
1984
)
14
Bensoussan
D
Le Deist
F
Latger-Cannard
V
, et al. 
T-cell immune constitution after peripheral blood mononuclear cell transplantation in complete DiGeorge syndrome.
Br J Haematol
2002
, vol. 
117
 
4
(pg. 
899
-
906
)
15
Daguindau
N
Decot
V
Nzietchueng
R
, et al. 
Immune constitution monitoring after PBMC transplantation in complete DiGeorge syndrome: an eight-year follow-up.
Clin Immunol
2008
, vol. 
128
 
2
(pg. 
164
-
171
)
16
Hoenig
M
Schulz
A
Schuetz
C
Debatin
K-M
Friedrich
W
Treatment of complete DiGeorge syndrome by repeat transfusions of blood lymphocytes from an HLA-identical sibling donor.
ASH Annual Meeting Abstracts
2004
, vol. 
104
 
11
pg. 
1332
 
17
Mayumi
M
Kimata
H
Suehiro
Y
, et al. 
DiGeorge syndrome with hypogammaglobulinaemia: a patient with excess suppressor T cell activity treated with fetal thymus transplantation.
Eur J Pediatr
1989
, vol. 
148
 
6
(pg. 
518
-
522
)
18
Thong
YH
Robertson
EF
Rischbieth
HG
, et al. 
Successful restoration of immunity in the DiGeorge syndrome with fetal thymic epithelial transplant.
Arch Dis Child
1978
, vol. 
53
 
7
(pg. 
580
-
584
)
19
Markert
ML
Devlin
BH
Chinn
IK
McCarthy
EA
Li
YJ
Factors affecting success of thymus transplantation for complete DiGeorge anomaly.
Am J Transplant
2008
, vol. 
8
 
8
(pg. 
1729
-
1736
)
20
Hoover-Fong
J
Savage
WJ
Lisi
E
, et al. 
Congenital T cell deficiency in a patient with CHARGE syndrome.
J Pediatr
2009
, vol. 
154
 
1
(pg. 
140
-
142
)
21
Markert
ML
Treatment of infants with complete DiGeorge anomaly.
J Allergy Clin Immunol
2008
, vol. 
121
 
4
pg. 
1063
  
author reply 1063–1064
22
Land
MH
Garcia-Lloret
MI
Borzy
MS
, et al. 
Long-term results of bone marrow transplantation in complete DiGeorge syndrome.
J Allergy Clin Immunol
2007
, vol. 
120
 
4
(pg. 
908
-
915
)
23
Buckley
RH
Schiff
SE
Schiff
RI
, et al. 
Hematopoietic stem-cell transplantation for the treatment of severe combined immunodeficiency.
N Engl J Med
1999
, vol. 
340
 
7
(pg. 
508
-
516
)
24
Grunebaum
E
Mazzolari
E
Porta
F
, et al. 
Bone marrow transplantation for severe combined immune deficiency.
JAMA
2006
, vol. 
295
 
5
(pg. 
508
-
518
)
25
Antoine
C
Muller
S
Cant
A
, et al. 
Long-term survival and transplantation of haemopoietic stem cells for immunodeficiencies: report of the European experience 1968–99.
Lancet
2003
, vol. 
361
 
9357
(pg. 
553
-
560
)
26
Neven
B
Leroy
S
Decaluwe
H
, et al. 
Long-term outcome after hematopoietic stem cell transplantation of a single-center cohort of 90 patients with severe combined immunodeficiency.
Blood
2009
, vol. 
113
 
17
(pg. 
4114
-
4124
)