The etiology of rheumatoid arthritis (RA) is not clear. Evidence of limited usage of T cell receptor V beta genes has been found in rheumatoid synovium. Therefore, a pathological mechanism in which superantigens (SAgs) activate T cells with particular T cell receptor V beta chains may exist. However, no direct functional studies of this possible mechanism have yet been reported. In this study we investigated the direct functional responses of lymphocytes from patients with RA to different bacterial superantigens.
A primary lymphocyte proliferation test to four different staphylococcal enterotoxins (SEs) was performed in 36 patients with RA to gather information about the relationship between SAg and RA.
The results showed that patients with RA had a decreased proliferative response to all four SEs compared with normal subjects. The decreased response was also found in Con A stimulation. This decreased proliferative response to SEs was not unique to RA patients, but was also observed in patients with systemic lupus erythematosus.
We hypothesize that this decreased response to SEs only reflects the generalized immunodeficient status of patients with RA. The results do not suggest that any of the four SEs are involved in the pathogenesis of RA.