COXSACKIE B1 VIRUS-INDUCED MURINE MYOSITIS - A CORRELATIVE STUDY OF MUSCULAR LESIONS AND SEROLOGICAL CHANGES

We investigated the role of humoral factors in the pathogenesis of Cox sackie B1 virus-induced murine myositis (CB1-myositis). At 2, 4 and 8 weeks after inoculation, serum was studied for circulating immune comp lexes (CIC) (Raji-cell assay), haemolytic complement activity (CH50 ti tre) and anticytoplasmic autoantibodies (Western blotting, immunopreci pitation) in relation to degree of mononuclear cell infiltration and m uscle fibre necrosis. At 2, 4 and 8 weeks, cell infiltration correlate d positively to muscle fibre necrosis. From 2 weeks on, moderate quant ities of CIC were found in nearly all CB1-inoculated mice, but without correlation to histological changes. Except for a positive correlatio n of CH50 titre to muscle necrosis at 4 weeks (r=0.60; P=0.02), CH50 t itres did not correlate to muscle lesions. Anticytoplasmic and other k nown autoantibody specificities were absent. In conclusion, first, in CB1-myositis CIC occurred from 2 weeks on, but no correlative evidence was found for their involvement in pathogenesis, neither for that of complement nor for anticytoplasmic autoantibodies. Secondly, cell infi ltration correlated positively to muscle necrosis, underscoring the im portance of cellular mechanisms. Thus, our data do not support, or con clusively exclude, a role for humoral processes in CB1-myositis.