T-LYMPHOCYTE RESPONSES TO ANTINEUTROPHIL CYTOPLASMIC AUTOANTIBODY (ANCA) ANTIGENS ARE PRESENT IN PATIENTS WITH ANCA-ASSOCIATED SYSTEMIC VASCULITIS AND PERSIST DURING DISEASE REMISSION

ANCA with specificity for myeloperoxidase (MPO) and proteinase 3 (PR3) are present in patients with systemic vasculitis. The aim of this wor k was to determine whether such patients have T cell responses to thes e antigens and whether these responses are related to disease activity . Peripheral blood lymphocytes from 45 patients and 19 controls were c ultured with ANCA antigens and proliferation measured. The antigens us ed were heat-inactivated (HI) MPO, HI PR3, native (non-HI) PR3, HI who le alpha-granules, and 25 overlapping peptides covering the entire PR3 sequence. Significant responses to both whole PR3 preparations were s een from patient and control groups, and to the alpha-granules from th e patient group. Patients responded at all stages of disease: active, remitting, treated or untreated. Only two patients responded significa ntly to MPO. Responses were significantly higher with the patient grou p than the control group to all four whole ANCA antigens. Responses to those PR3 peptides containing epitopes known to be recognized by ANCA were detected from one patient. Thus, these studies demonstrate that T cells from vasculitis patients can proliferate to PR3 and occasional ly to associated ANCA antigens. Further, responses may persist even af ter disease remission has been achieved.