Spontaneous and induced immunoglobulin synthesis and anti-neutrophil cytoplasm antibodies in Wegener's granulomatosis: relation to leukocyte subpopulations in blood and active lesions.

Using a reverse plaque forming cell (PFC) assay the production of immunoglobulin (Ig) by peripheral blood mononuclear cells (MNCs) in vitro was studied in 12 patients with Wegener's granulomatosis (WG). Spontaneous IgG production was increased in two of six untreated patients. The IgG response of MNCs from eight untreated patients to pokeweed mitogen (PWM) and Epstein-Barr virus (EBV) stimulation was significantly depressed. The IgM and IgA production followed the individual pattern of IgG. Blood B-cell and T-cell subset concentrations were normal before therapy, whereas the monocyte concentration was increased in four of six patients. Titers of anti-neutrophil cytoplasm autoantibodies (ANCAs) did not correlate with spontaneous or induced Ig production nor with blood leukocyte subset concentrations. Biopsy specimens from upper respiratory tract lesions in seven untreated patients showed numerous macrophages, activated T lymphocytes, and plasma cells, suggesting a pathogenetic role of these cells in the development of lesions and local production of ANCAs.