Characterization of CD3+ CD4- CD8- (double negative) T cells in patients with systemic lupus erythematosus: production of IL-4.

Systemic lupus erythematosus (SLE) is a chronic autoimmune rheumatic disease that may affect every organ or system in the body. We have shown previously that the TCR alphabeta+ subpopulation of CD3+ CD4- CD8-, DN T cells is expanded in patients with SLE and that double negative T cells express increased levels of activation markers compared both with healthy people and with patients with rheumatoid arthritis, (RA) as autoimmune controls. The aim of this study was to characterize these cells in terms of their ability to produce IL4, a Th2 cytokine, both spontaneously and after mitogen stimulation.