Autoimmune neutropenia: clinical and laboratory studies in 143 patients.

Clinical and laboratory data of 143 patients with primary or secondary autoimmune neutropenia (AIN) were evaluated. Primary AIN was found predominantly in children below 3 years, whereas secondary AIN was more frequent in patients 40-60 years of age. Female patients with primary AIN were slightly more prevalent (54%) than male patients (46%). The peripheral blood count showed normal or diminished leukocyte counts with median absolute neutrophil counts of 250 cells/microliters. In 38% of the patients neutropenia was accompanied by monocytosis. Bone marrow examination revealed in 95% a normo- or hypercellular marrow with a marked reduction of mature neutrophils in 56% of the specimens. Twenty-three percent of the sera showed specificity for the NA1 antigen. Patients were usually affected by benign bacterial infections of the skin and of the upper respiratory tract, as well as by recurrent otitis media. Infections were treated symptomatically, and only six patients required continuous administration of antibiotics. Remission of neutropenia during treatment occurred in three of six patients treated with intravenous immunoglobulin G and in three of four patients who received steroid therapy. Except for one patient neutropenia relapsed after discontinuation of therapy. During a follow-up of 6-36 months, spontaneous remission has been observed in four patients.