Differential sensitivity of functional subsets of t cells to the cytotoxicity of natural t‐lymphocytotoxic autoantibody of systemic lupus erythematosus

Abstract

A naturally occurring T‐lymphocytotoxic autoantibody (Hu‐NTA) in serum from a patient with systemic lupus erythematosus (SLE) showed a differential cytotoxic effect on functionally different T cell subsets as did natural thymocytotoxic autoantibody (NTA) of NZB mice. When the normal peripheral blood lymphocytes were treated, in the presence of complement, with Hu‐NTA at a dilution that eliminated 25 to 30% of Hu‐NTA‐sensitive T cells, there was a marked reduction or a total depletion in the ability of resultant cells to show Con A‐activated suppression on the proliferative response of responder cells in mixed lymphocyte reaction. The treatment of PBL in the same manner also resulted in a marked reduction in its responsiveness to Con A and PHA. However, the responder cells to allogeneic stimulator cells in MLR were found to be much more resistant to the cytotoxicity of Hu‐NTA than other functional T cell subsets tested. These results suggest that Hu‐NTA is responsible for the selective loss of certain functional T cell subsets including suppressor T cells in patients with SLE.