Increased expression of membrane TNF-α on activated peripheral CD8+ T cells in systemic lupus erythematosus

Membrane TNF-α is a precursor form of soluble TNF-α and exerts pro-inflammatory functions in a cell-to-cell contact manner. We showed that membrane TNF-α is induced upon activation on the cell surface of CD4+ T cells and CD8+ T cells. In patients with systemic lupus erythematosus (SLE), the percentage of membrane TNF-α-bearing CD8+ T cells (41.5±12.3%) was significantly higher compared with those of healthy controls (26.7±3.9%) (p=0.007) or patients with rheumatoid arthritis (29.8±15.4%) (p=0.038). Membrane TNF-α-bearing CD8+ T cells from SLE patients displayed cytotoxic activity against L929 cells. It is possible that membrane TNF-α may be involved in the increased apoptosis and the generation of autoantigens in SLE.