ANTINEUTROPHIL CYTOPLASMIC ANTIBODY (ANCA) IN MALARIA IS DIRECTED AGAINST CATHEPSIN-G

Autoantibodies of diverse specificities are detected in sera of patien ts with acute malaria. The clinical relevance of these autoantibodies is not clear, though there are reports associating some autoantibodies with specific disease manifestations. We have investigated the occurr ence of ANCA in the sera of 93 patients during episodes of acute malar ia. Sera were tested by indirect immunofluorescence (IIF) and by ELISA for antibodies to neutrophil cytoplasmic components proteinase 3(PR3) , myeloperoxidase (MPO), cathepsin G (CG), human leucocyte elastase (H LE), and lactoferrin (LF). Forty-seven sera samples (50.5%) were posit ive by IIF, all except one with the atypical ANCA pattern (a-ANCA). Wh en screened by ELISA, anti-CC antibodies were detected in 52 samples ( 56%), while anti-PR3 and anti-MPO antibodies were detected in three an d one samples, respectively. Antibody binding to HLE and LF was not si gnificant. Anti-CC antibodies were detected in 93% of the IIF-positive sera. A combination of anti-CC and anti-PR3 antibodies was noted in t hree samples. Our study demonstrates the presence of ANCA in sera from patients with acute malaria, almost all with the a-ANCA pattern on II F. The antibody specificity, noted for the first time in our study, ap pears to be predominantly directed against CG. The significance of CG and CG-ANCA in the pathogenesis and clinical manifestations of malaria has yet to be elucidated.