Evidence of diminished suppressor T cell activity in patients with atopy and SLE.

The T cell mitogen concanavalin A (Con A) was added to lymphocytes pre-cultured for 24 hours in vitro in tissue culture medium. Delayed addition of the mitogen resulted in an enhanced lymphocyte activation measured by incorporation of radioactive precursors of DNA. T cells isolated by rosetting with sheep erythrocytes also exhibited this enhancement. In a limited study, lymphocytes from both atopic patients and those with systemic lupus erythematosus (SLE) showed little or no enhanced responsiveness to Con A. The possibility that some patients with atopy and SLE possess defective suppressor T cells is discussed in the light of these data.