Tγ cell subset specificity of lymphocyte reactive factors in juvenile rheumatoid arthritis and systemic lupus erythematosus sera

Abstract

Sera from 34 patients with juvenile rheumatoid arthritis (JRA), 31 patients with systemic lupus erthematosus (SLE), and 22 normal controls were studied for microcytotoxicity before and after clearing in the ultracentrifuge. Normal T cells as well as Tγ and non-Tγ subpopulations were used. Before ultracentrifugation all test sera showed apparent Tγ cell specificity in the microcytotoxicity assay where rabbit complement was added. JRA and SLE sera produced much higher proportions of cell killing than normal controls. Ultracentrifugal clearing resulted in marked diminution in microcytoxicity of JRA and some SLE sera. However, a considerable proportion of lupus sera continued to show T cell subset cytotoxicity after ultracentrifugal clearing. No evidence for significant alteration of Tγ resetting capacity was recorded when ultracentrifuge-cleared test sera were preincubated with T cells prior to Tγ EA rosette formation. Apparent Tγ cytotoxic specificity in some uncleared JRA and SLE sera may relate to high molecular weight materials (IgM and immune complexes) present in such samples, whereas in others it relates to lymphocyte reactive antibody with subset reactivity.