Similar levels of immune complexes in cases of multiple sclerosis and their unaffected relatives.

To investigate the possible effect of the hypothetical multiple sclerosis susceptibility (MSS) gene on circulating immune complexes, we employed a sensitive assay to test for the presence of immune complexes in sera of MS patients and unaffected relatives classified by the presence/absence of HLA-defined markers for the MSS gene. We found no significant differences between cases and relatives. The results suggest that elevated immune complex levels in MS patients' sera reported by others may not be unique to MS cases, but may represent instead a familial phenomenon. We also report a possible association between the A3 + B7 haplotype and increased immune complexes.