Heterogeneity of antilymphocyte antibody in SLE and its correlation with disease activity

The cytotoxic activities of individual lupus sera were demonstrated against T gamma cells, T gamma (-) cells and B cells. Immunoglobulin classes were also determined in these antilymphocyte antibodies (ALA) in SLE. T gamma-specific ALA and B-cell-specific ALA were almost equally distributed as regards IgG-dominant type, mixed IgG and IgM type and IgM dominant type, while IgM dominant type was predominant in T gamma (-)-specific ALA. Only the IgG type of T gamma-specific ALA among these ALA was significantly associated with clinical parameters, including hypocomplementemia, elevated immune complex levels and high anti-double-stranded (ds) DNA titres. Serial studies on ALA in a typical case of SLE were performed. Active clinical signs were associated with elevated cytotoxicities of IgG type of T gamma-specific ALA and with relatively low cytotoxicities of the IgM type, whereas after massive corticosteroid therapy, these signs disappeared in tact with the reduction in cytotoxic activities of IgG type of the ALA and the relative rise in cytotoxicities of IgM type of the ALA. These results suggested that IgG class of T gamma-specific ALA seemed to play a major role among several types of ALA in SLE.