Down-regulation of natural killer cells and of gamma/delta T cells in systemic lupus erythematosus. Does it correlate to autoimmunity and to laboratory indices of disease activity?

A depletion of natural killer (NK) cells seems to play a role in the course of systemic lupus erythematosus (SLE) whereas the possible involvement in this disease of T cell receptor (TCR) gamma/delta positive T cells is still debated. The aim of this study was to evaluate the peripheral blood mononuclear cells (PBMCs) that express NK surface markers CD16 and CD56 or gamma/delta TCR antigen in 58 SLE patients, investigating the possible role of these cell subsets involved in non-MHC-restricted cytotoxicity and their relationship with the main clinical and laboratory parameters. SLE patients had, with respect to controls, considerably decreased values of NK cells (P<0.