Mikulicz's recurrent oral aphthae: the effect of anti-lymphocyte serum upon the in vitro cytotoxicity of lymphocytes from patients for oral epithelial cells.

Preincubation with rabbit anti-human lymphocyte serum suppressed the in vitro cytotoxicity of peripheral blood lymphocytes from patients suffering from Mikulicz's recurrent oral aphthae for oral epithelial cells. Further studies revealed that although the anti-lymphocyte antibody remained bound to the lymphocytes after the pre-incubation procedure it exerted no demonstrable cytotoxic effect and induced a minimal degree of transformation. The mechanisms by which the anti-lymphocyte serum may have suppressed the lymphocytotoxicity are discussed.