[Antibodies directed against the cytoplasm of granulocytes. Diagnostic value in vasculitis]

The demonstration of antibodies directed against granulocyte cytoplasm in Wegener's disease and in the microscopic forms of polyarteritis nodosa led to the proposal that these antibodies could be used as a diagnostic tool and a means to monitor the evolution of these diseases. However, the presence of these antibodies in different pathological situations and, in particular, in syndromes not related to vasculitides, poses the question as to their specificity. In addition, the observation of dissociated reactions between the methods available for the detection of these antibodies (indirect immunofluorescence, radioimmunological assay), like the existence of different morphological aspects seen in immunofluorescence, favor the hypothesis of different antigenic determinants, whose recognition could contribute to the nosology and pathophysiology of these diseases. We performed a retrospective study based on 42 positive results (paired execution of both detection techniques), in order to characterize the corresponding anatomic and clinical states. We confirmed the classical positivity in Wegener's disease and microscopic forms of polyarteritis nodosa, justified the paired running of both detection assays because of dissociated results and false positives found by immunofluorescence, corroborated the presence of antibodies in conditions apparently unrelated to vasculitides, and specified the different aspects observable by immunofluorescence, thus demonstrating the reality of different antigenic determinants.