Autoantibodies against cytoplasmic structures of neutrophil granulocytes in Wegener's granulomatosis.
Autoantibodies against cytoplasmic components of neutrophil granulocytes (ACPA) were detected in 18 of 32 patients with Wegener's granulomatosis (WG), but in none of the controls (n = 900), including patients with glomerulonephritis, sarcoidosis, tuberculosis, polyarteritis nodosa, and connective tissue diseases, and healthy blood donors. The presence and, to a lesser extent, the titre of ACPA correlated with the severity and activity of the disease. ACPA could be detected in only three of 11 patients with the limited form of the disease and in none in complete remission. In contrast, in all patients with active extensive disease, ACPA were present in a higher titre, and in most of the patients in partial remission (eight of 12) antibodies were demonstrable, especially in those with frequent relapses. Furthermore, the antibody titre correlated significantly with the C-reactive protein concentration (P less than 0.05), but with none of the other laboratory parameters. In conclusion, ACPA have proven to be a highly specific disease marker of great clinical significance that provides us with a useful tool to confirm, or even establish. the diagnosis of WG.