Immunoglobulin and B-cell disturbances in patients with chronic idiopathic neutropenia

Abstract Chronic idiopathic neutropenia (CIN) is a granulocytic disorder associated with presence of activated, myelosuppressive T-lymphocytes. In the present study we have evaluated constituents of humoral immunity in CIN patients ( n  = 48) compared to healthy controls ( n  = 52). CIN patients displayed lower serum IgG levels due to a reduction in IgG1, IgG3, IgG4 but not IgG2, lower IgA and increased IgM levels compared to controls. The proportion of CD19 + cells did not differ between patients and controls; however the proportion of the naive IgD + /CD27 − B-cells was increased and the proportion of class-switched memory IgD − /CD27 + B-cells was decreased in the patients. The percentage of CD40 + B-cells did not differ between patients and controls and no aberrations in the CD40-meadiated signal transduction pathway or in CD40-gene polymorphisms were identified. These data provide further evidence that immune disturbances are associated with the pathophysiology of CIN and point out for the first time the implication of the B-cell system.