beta 2 microglobulin binding activity associated with lymphocytotoxic antibodies in sera containing multiple...

Lymphocytotoxic antibodies (LCA) determined by complement-dependent lysis at room temperature were detected in sera containing antibodies reactive with cell nuclear (ANA) or thyroid antigens (ATA); however, the prevalence of LCA was significantly increased in sera containing both ANA and ATA. Strongly reactive LCA were only partially inhibited by beta 2-microglobulin (beta 2m) in lymphocytoxicity. Serum binding to beta 2m, determined by an enzyme-linked solid phase immunoassay (ELISA), however, was significantly increased in LCA-positive sera compared with both LCA-negative sera and normal sera; moreover, serum binding to beta 2m was significantly correlated with the frequency of LCA. There was no correlation between serum binding to beta 2m and levels of either serum immunoglobulin or serum beta 2m. These data have indicated that the prevalence of LCA in sera containing ANA was significantly associated with the separate presence of ATA suggesting some form of common escape from immunoregulation of autoimmunity; LCA activity was strongly correlated with increased serum binding to beta 2m.