Severe chronic primary neutropenia in adults: Report on a series of 108 patients

Abstract

Severe chronic primary neutropenia (CPN) is a rare entity, and long-term outcome and risk factors for infections in severe CPN adults have not been described to date.We report the characteristics and outcomes of 108 severe adult CPN patients enrolled in a multiinstitutional observational study. SevereCPNadultsweremostly female (78%), andmedian age at diagnosis was 28.3 years. Diagnosis was fortuitous in 62% of cases. The median absolute neutrophil count (ANC) at diagnosis was 0.4 × 109/L, and median ANC without granulocyte colony-stimulating factor (G-CSF) during follow-up was 0.5 × 109/L. Twentythree of 66 (34.8%) evaluable patients had neutrophil autoantibodies, and 6 of 47 (12.8%) a T-cell clone. The presence of neutrophil autoantibodies orT-cell clonewas not associated with any specific clinical or biological characteristics. No death or hematologic malignancies occurred, and 44 severe bacterial infectionswere reported in 27 patients with amedian follow-up of 8.3 years. Fifty patients received G-CSF either sporadically (n = 24) or continuously (n = 26) and responded (96%). Nineteen patients received immunosuppressive therapies: overall response (OR) was 41%, and median duration of response was 3 months. At diagnosis, the only predictive factor for the occurrence of severe bacterial infections was an ANC count below 0.2 × 109/L (OR, 0.76). Severe CPN in adults is characterized by a female predominance and a benign outcome with a low rate of severe bacterial infections and no secondary malignancies. G-CSF is efficient and well tolerated but is not required in a majority of patients.