C1q autoantibodies in HIV infection: Correlation to elevated levels of autoantibodies against 60-kDa heat-shock proteins

Antibodies to solid phase C1q (C1qAb) were determined in 295 serum samples from 132 HIV-infected subjects and in sera from 140 HIV-seronegative health y individuals as control. An ELISA method applied for the determination of C1qAb in other diseases was used. In part of these sera, other autoantibodi es (antibodies reacting with 60-kDa human heat shock protein (hsp60) or myc obacterial hsp65; IgA and IgG class antibodies against the Fab and F(ab')2 moieties of IgG) as well as complement-mediated antibody-dependent enhancem ent/neutralization (C'-ADE) were also determined, Increased amount of C1qAb was found in HIV-infected subjects as compared with HIV-seronegative contr ols (P = 0.0138), In 17 of 132 (13.0%) seropositive individuals but only in 7/140 (5.0%) samples from the controls, the amount of C1qAb exceeded the u pper limit (95th percentile) of the normal values (P = 0.031). The amount o f C1qAb significantly decreased during a follow-up period of 65 months. C1q Ab levels were found to strongly correlate to hsp60/65 autoantibodies but d id not correlate or only weakly correlated to the amount of anti-Fab or ant i-F(ab')(2) autoantibodies measured in the same serum samples. Anti-C1q ant ibodies recognized the solid phase hsp60/65. Three predicted epitope region s of M. paratuberculosis hsp65 were able to bind efficiently C1q antibodies . An inverse correlation was found between C1qAb and C'-ADE, neutralization was more frequent in the sera with detectable C1qAb, whereas sera without C1qAb more likely enhanced HCV infection in vitro. (C) 1999 Academic Press.