Immunoregulatory function of T8 and T4 cells from synovial fluid and blood of patients with rheumatoid arthritis or other forms of chronic arthritis.

The suppressor effect of synovial fluid (SF) T8 cells and blood T8 cells on the pokeweed mitogen (PWM)-induced T4 cell-dependent immunoglobulin production of autologous blood B cells was studied in nine patients with chronic rheumatic diseases (six patients with rheumatoid arthritis (RA), one patient with juvenile RA, and two patients with other forms of chronic arthritis). The suppressor effect of SF T8 cells was of the same magnitude as that of equal numbers of blood T8 cells from patients and healthy controls. However, the relative number of T8 cells was higher among SF T cells than among blood T cells in several cases. Good synovial T8 cell suppression was also demonstrated in coculture experiments where SF T4 cells and B cells were used. In PPD (purified protein derivative of tuberculin)-stimulated cultures the suppressor effect of SF T8 cells as well as of blood T8 cells from patients and controls was lower than it was in PWM-stimulated cultures. In most patients SF T4 cells showed a much better PWM-induced helper function than did non-fractionated SF T cells. Thus the poor PWM induced helper effect of non fractionated synovial T cells was in some cases mainly due to the suppressor effect of T8 cells, whereas in some cases there was also a deficient helper function of synovial T4 cells.