Deficient lymphoid cell-mediated, PHA-induced cytotoxicity in rheumatoid arthritis patients.

Lymphoid cells from patients with rheumatoid arthritis were compared with those from healthy blood donors and from nonrheumatoid arthritis patients for the ability to manifest in vitro cytotoxicity against target cells in the presence of phytohemagglutinin (PHA) or anti-target cell antibodies. The PHA-induced cytotoxicity in the rheumatoid patient group was significantly lower than that of the blood donors (P less than 0.01) and of the nonrheumatoid patients (P less than 0.05). The rheumatoid arthritis patients appeared to fall into two groups, one with normal and one with distinctly subnormal PHA-induced cytotoxicity. No obvious differences were observed betes, or the proportion in peripheral blood of T lymphocytes (E-RFC) or Fc-receptor-bearing lymphocytes (EA-RFC). There were no significant differences between the groups with regard to antibody-dependent cytotoxicity.