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<0.0004 in percentage and P<0.00004 as absolute number), of non-MHC-restricted T cytotoxic lymphocytes (P<0.007 and P<0.0015, respectively) and of T cells expressing gamma/delta TCR (P<0.02 and P<0.004, respectively). The absolute numbers of these cell subsets positively correlated to each other (P<0.009). gamma/delta T cells inversely correlated with higher ESR values, both percentually (P<0. 006; r=-0.367) and in absolute number (P<0.009; r=-0.350). Moreover, the percentage values of this cell subset inversely correlated with higher levels of CRP (P<0.05; r=-0.256) while SLE patients with anti-SSB/La antibodies had lower values of T lymphocytes bearing gamma/delta TCR, both as percentage (P<0.008) and as absolute number (P<0.02). Our study indicates that non-MHC-restricted cytotoxicity, shared by NK, NK-like and gamma/delta T cells, may be down-regulated in SLE patients, owing to a significant reduction of these PBMC subsets. These specific cell subset impairments seem to affect only some aspects of the disease, suggesting a weakening of the regulatory properties of these cells in the control of different immunological and inflammatory features of SLE, that could be of importance in its clinical expression.
Riccieri
V
V
Department of Medical Therapy, University 'La Sapienza', Rome, Italy.
Spadaro
A
A
Parisi
G
G
Taccari
E
E
Moretti
T
T
Bernardini
G
G
Favaroni
M
M
Strom
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D015551:Autoimmunity; D002648:Child; D015536:Down-Regulation; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D016692:Receptors, Antigen, T-Cell, gamma-delta