Imbalance between CD8CD28 and CD8CD28 T-cell subsets and its clinical significance in patients with systemic lupus erythematosus.

OBJECTIVE

The aim of this study was to evaluate the changes in CD8CD28/CD8CD28 T-cell subset balance and in the CD8CD28 Treg cell number and function in patients with systemic lupus erythematosus (SLE).

METHODS

Cell isolation and flow cytometry analysis were employed to investigate the T-cell subsets.

RESULTS

It was found that in high-activity SLE patients, the CD8CD28 T-cell subset was reduced, which was inversely correlated with the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and that the CD8CD28/CD8CD28 ratio was elevated, which was positively correlated with SLEDAI and with renal damage and inversely correlated with serum complement level, whereas the CD8CD28 T-cell subset was increased only in inactive patients. It was also found that apoptosis of CD8 T cells increased, and Fas, Fas ligand (FasL) and interleukin (IL)-6 expression were high, whereas cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) expression was low by the CD8CD28 T cell subset in active SLE patients; apoptosis was positively correlated with SLEDAI and with the expression of Fas and FasL by the CD8CD28 T-cell subset in active SLE patients. IL-6 and CTLA-4 expression were found to be low by the CD8CD28 T cell subset in active SLE patients.

CONCLUSION

These data suggest that high expression of Fas, FasL and IL-6 and low expression of CTLA-4 by the CD8CD28 T-cell subset promotes the activation-induced cell death of the CD8CD28 T-cell subset, resulting in an imbalance of CD8CD28/CD8CD28 T cells in active SLE patients, which represents an important feature in the immunological pathogenesis of SLE. The CD8CD28 T-cell subset may play some role in inactive SLE.