Microsoft Word - NEF504BF

Dr. Xavier Bosch, Servicio de Medicina Interna General, Unidad 1, Hospital Clínico y Provincial, Villarroel, 170, E-08036 Barcelona (Spain) Dear Sir, Nässberger et al. [1] have recently reported the occurrence of anti-neutrophil cytoplasmic autoantibodies (ANCA) in sera from patients with crescentic glomerulonephritis (CGN). Among 64 patients with this disease, ANCA were detected in 47 (73%). By indirect immuno-fluorescence, a cytoplasmic pattern (C-ANCA) was seen in 44% of the patients, mainly in those having a diagnosis of Wegener’s granulomatosis (WG). In contrast, a perinuclear pattern (P-ANCA) was seen in 30%, mainly in those with CGN without evidence of extrarenal involvement. Furthermore, as judged by enzyme-linked immunosorbent assay (ELISA), all P-ANCA sera corresponded to anti-myeloperoxidase (MPO) antibodies. We wish to report our experience of ANCA in CGN. Our study included a series of 24 consecutive patients with a pathological diagnosis of CGN. ANCA were tested by an indirect immunofluorescence assay on etha-nol-fixed neutrophils, as previously described [2]. In addition, we realised a previously unpublished method in order to know in which cases ANCA were directed against MPO. Thus, indirect immunofluorescence was also performed on neutrophils which were previously known to have an absence of this enzyme. This rare condition may be easily detected in an ordinary blood analysis using a Technicon H-l autoanalyzer (Technicon, Tarrytown, N.Y., USA). Sera giving a positive result with normal neutrophils and a negative one with neutrophils devoid of MPO were considered to possess anti-MPO antibodies. These results were later confirmed by ELISA using purified human MPO. 1 Supported in part by grants from the Hospital Clínico y Provincial de Barcelona (1990) and the Direcció General d’Universitats de la Generalitat de Catalunya (Formació d’investigadors 1990). Table 1. Distribution of ANCA in 24 consecutive patients with CGN Patients ANCA CPMPOn ANCA ANCA ANCA Idiopathic CGN 19 12 2 10 10! PAN-associated CGN 4 4 0 4 4 WG-associated CGN 1 110 0 Six males and 4 females.