Gonococcal arthritis-dermatitis syndrome. Study of serum and synovial fluid immune complex levels

Immune complexes from serum and synovial fluid were detected by the C1q binding assay in 12 patients with disseminated gonococcal infection. Since immune complexes were regularly higher in synovial fluids than in paired sera and were not detected by the monoclonal rheumatoid factor radioimmunoassay, we suggest that IgM may be present in these complexes and that this represents a primary immune response. In contrast, only 2 of 10 patients with local gonococcal infection were slightly positive both with the C1q assay and the monoclonal rheumatoid factor assay. In patients with disseminated gonococcal infection, immune complexes closely paralleled the disease activity and negatively correlated with complement levels. Synovial fluid immune complexes seem to occur in the early and aseptic phase of polyarthritis and to aid the entrance of circulating gonococcal organisms. From the results of our study, it seems that immunologic processes initiate and/or sustain inflammation in disseminated gonococcal infections that appear, at least in part, as a form of reactive arthritis.