IMPAIRED NONRESTRICTED CYTOLYTIC ACTIVITY IN SYSTEMIC LUPUS-ERYTHEMATOSUS - INVOLVEMENT OF A PATHWAY INDEPENDENT OF FAS, TUMOR-NECROSIS-FACTOR, AND EXTRACELLULAR ATP THAT IS ASSOCIATED WITH LITTLE DETECTABLE PERFORIN

Objective. To determine the cytolytic effector pathway involved in imp aired generation of nonrestricted cytolytic activity in systemic lupus erythematosus (SLE). Methods. Peripheral blood mononuclear cells (PBM C) from normal subjects and SLE patients were stimulated in vitro with anti-CD3 monoclonal antibody (MAb) and interleukin-2 to promote the g eneration of nonrestricted cytolytic activity, On day 13 of culture, t he PBMC were assayed for cytolytic activity against Fas-Daudi cells an d Fas+ Jurkat cells, The effects on cytotoxicity of calcium chelation, antagonist anti-Pas MAb, tumor necrosis factor (TNF) alpha and beta a nd ATP were measured, Intracellular perforin expression was determined by intracellular staining, and perforin messenger RNA levels were det ermined by quantitative competitive reverse transcription-polymerase c hain reaction. Results. We demonstrated the existence of a cytolytic p athway that is independent of Fas, TNF alpha, TNF beta, and ATP, but i s dependent upon extracellular calcium. Despite its calcium dependence , this pathway is associated with low-to-undetectable levels of perfor in. Conclusion. Impaired generation of nonrestricted cytolytic activit y in SLE is likely due to decreased activity of this Fas-, TNF alpha-, TNF beta-, ATP-independent pathway associated with very low levels of perforin.