Background: Since 1994 the Severe Chronic Neutropenia International Registry (SCNIR) has enrolled children and adults with > 3 absolute neutrophil counts (ANCs) < 0.5 x 109/L during a 3 month period to understand the pathobiology, natural history and treatment responses for severe chronic neutropenia. We have previously reported on the frequency and risk of myelodysplasia (MDS) and acute myeloid leukemia (AML) in patients with congenital neutropenia. For this report we reviewed patterns of hematological complications and malignancies occurring in all patients enrolled through the North American office of the SCNIR.
Methods: Enrollment required informed consent, and patients and their physicians provided demographic, clinical and laboratory data including bone marrow results. Genetic testing was not required. Patients were followed with annual reports on blood counts, infections, malignancies and hospitalizations.
Results: From 1994 to 2018 the Seattle SCNIR office has enrolled 1672 patients in the following categories: congenital 637 (38%), cyclic 259 (15%), and idiopathic / autoimmune 776 (47%), and many have been followed now for more than 15 years. There are approximately 17,577 person years of the observational data in this Registry. The congenital category now includes patients with mutations in ELANE, SBDS, TAZ, COH1, CXCR4, SLC37A4, G6PC3, WAS, CSF3R, SRP54, GFI1, VPS45, JAGN1, HAX1 and also patients with severe neutropenia from an early date in childhood without a genetic diagnosis. Cyclic neutropenia patients have demonstrated oscillations in ANC. The idiopathic and autoimmune category includes children and adults including some with large granular lymphocytes (LGL) syndrome without recognized features of a lymphoproliferative disorder. Most patients in all categories have been treated with granulocyte colony-stimulating factor (G-CSF).
Findings: MDS or AML has occurred in 70 of the 1672 patients; 99% have clinical diagnosis of a hereditary type of neutropenia: severe congenital neutropenia (55), glycogen storage disease 1b (3), congenital immunodeficiency (2), Shwachman-Diamond syndrome (SDS) (5), WHIM syndrome (1),Wiskott-Aldrich syndrome (2), cyclic neutropenia (1) and idiopathic neutropenia (1). The median age at diagnosis of AML/MDS was 15.3 years (mean 18.3, +/- 1.79 SEM [range 0.40 - 70.6]); 69 of 70 were treated with G-CSF, median dose = 7.1 mcg/kg/day (mean 7.3, +/- 1.3 SEM )(range 0.18 - 100). One Shwachman-Diamond patient never received G-CSF. Outcomes for AML/MDS patients receiving chemotherapy with HSCT before 2000 were poor with 3/17 (18%) survivors. Since 2000 there were 35/53 (66%) survivors. Five patients developed myelofibrosis (4 congenital and 1 idiopathic). Two of the congenital patients later developed AML (1 living after treatment with a HSCT, 1 deceased). The clinical diagnosis of cyclic neutropenia has a favorable prognosis with G-CSF treatment, with only one probable case in 3,833 person years of clinical observation. 1
Twelve patients developed T-cell lymphoproliferative disorder (1 autoimmune neutropenia, 3 congenital neutropenia, 8 idiopathic neutropenia (4 with LGL features)). Five of these patients are living, all in the idiopathic group, 3 of 5 living patients have features of the LGL syndrome.
Ten patients have reported other hematological malignancies; CML in a congenital patient after treatment with HSCT (living), CLL in a cyclic patient (living), CMML in an idiopathic patient after treatment with a HSCT (deceased). Six of the 10 patients have developed lymphoma; cyclic neutropenia (1), idiopathic/autoimmune neutropenia (5). Only one SDS patient has developed aplastic anemia.
Other cancers/non-hematological malignancies have occured mostly in older patients: breast cancer (15) colon cancer (6), dermatological malignancies (13), hepatoma (1), lung cancer (1), prostate cancer (1), thyroid cancer (1).
Conclusions: The hematological consequences of severe chronic neutropenia depend on the underlying etiology. MDS and AML occur largely in patients with the congenital or hereditary neutropenias. The diagnosis of cyclic neutropenia and chronic idiopathic / autoimmune neutropenia portends a favorable prognosis, based on a total of 10482 person years of observation. Marrow failure and aplastic anemia are not expected consequences of severe chronic neutropenia.
Dale:Athelas, Inc.: Equity Ownership; Amgen: Consultancy, Research Funding; Sanofi-Aventi: Consultancy, Honoraria; Cellerant: Other: Scientific Advisory Board; Hospira: Consultancy; Prolong: Consultancy; Beheringer-Ingelheim: Consultancy; Coherus: Consultancy. Newburger:X4 Pharmaceutics: Consultancy, Honoraria; TransCytos LLC: Consultancy; Janssen Research & Development, LLC: Consultancy, Honoraria.
Asterisk with author names denotes non-ASH members.