[Anti-neutrophil cytoplasmic antibodies (ANCA) in the glomerulonephritis]

Ninety nine patients with biopsy-proven diagnosis of immunologic glomerular disease were included in this study: 13 with extracapillaris glomerulonephritis (ExGN), 38 with membranoproliferative GN (MPGN), 33 with mesangial proliferative GN (MesPGN), 5 with focal segmental glomerulosclerosis (FSGS), 5 with membranous nephropathy (MN), and 3 with minimal change nephropathy (MC). Sera of these patients were tested for the presence of anti-neutrophil cytoplasmic antibodies (ANCA) by standard indirect immunofluorescence (IIF). Specific antiproteinase 3 (anti-Pr 3) and anti-myeloperoxidase (anti-MPO) by ELISA were assayed in ANCA-positive patients. ANCA were detected by IIF and ELISA in sera from 28 patients (28%). Of the 28 patients, 3 had cytoplasmic ANCA (c-ANCA), while 25 had perinuclear pattern (p-ANCA). Two c-ANCA positive patients with anti-Pr3 belonged to group I (GN at time of diagnosis). Another c-ANCA positive patients suffering from GN belonged to group II (GN with restrained disease activity). Of the 25 p-ANCA positive patients, 23 belonged to group I, 1 to group II, and I to group III (active GN received immunosuppressive therapy for several months). Majority of ANCA positive patients with GN were complicated by extrarenal organs involvement. One c-ANCA positive patient had ExGN and two patients had MesPGN. Of the 25 p-ANCA positive patients, 7 had ExGN, 10 MPGN, 4 MesPGN, 2 FSGS, and 1 had MC. Five p-ANCA positive patients with ExGN were temporary dialysis-dependent. One of them died due to cardiac infarction, one became dialysis-dependent, there of them (treated also with plasma exchange) responded favorably to this treatment and after 3 to 12 months had life-sustaining renal function (s-creatinine < 265 umol/L; < 3 mg%). Renal-limited disease had 3 p-ANCA positive patients (anti-MPO) with ExGN another ANCA positive patient had extrarenal organs involvement. The majority of patients with low titer of ANCA by IIF and low concentration p-ANCA by ELISA had different morphological GN, in most cases MPGN. All c-ANCA positive patients had extrarenal organs involvement, mainly respiratory tract. One of them was dialysis-dependent, and two responded favorably to immunosuppressive therapy. It is concluded that the IIF and ELISAs for anti-Pr3, and anti-MPO have an acceptable performance and are useful in the diagnostic of patients with vasculitis. Vasculitis can be primary in patients with pauci-immune crescentic GN, or secondary to other disease processes including immune complex-mediated GN. IS treatment (methylpredisolone + cyclophospamide) of ANCA positive patients with renal insufficiency nad normal or enlarged renal size is favourable. In the patients with extrarenal organs involvement and without improvements in renal function, however, requirement of plasma exchange is considered.