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

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 multi-institutional observational study. Severe CPN adults were mostly female (78%), and median 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 × 10(9)/L, and median ANC without granulocyte colony-stimulating factor (G-CSF) during follow-up was 0.5 × 10(9)/L. Twenty-three of 66 (34.8%) evaluable patients had neutrophil autoantibodies, and 6 of 47 (12.8%) a T-cell clone. The presence of neutrophil autoantibodies or T-cell clone was not associated with any specific clinical or biological characteristics. No death or hematologic malignancies occurred, and 44 severe bacterial infections were reported in 27 patients with a median 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 × 10(9)/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.