Characterisation of the effector cells responsible for the in vitro cytotoxicity of blood leucocytes from aphthous ulcer patients for oral epithelial cells.

This study was designed to identify the cells responsible for the spontaneous cell mediated cytotoxic effect (SCMC) exerted by peripheral blood leucocytes from patients with recurrent aphthous ulceration, towards cultured oral epithelial cells. Peripheral blood leucocytes from recurrent aphthous ulceration patients exerted a significantly greater (p less than 0.01) degree of cytotoxicity towards the oral epithelial target cells than did peripheral blood leucocytes from healthy control subjects, or from patients with non-specific ulceration. Depletion of CD-5 positive cells (T-lymphocytes) resulted in a significant decrease in the SCMC in aphthous patients. Depletion of CD-16 positive cells (NK-cells) produced no significant change in cytotoxicity. T-lymphocytes, therefore, appear to be intimately involved in the in vitro SCMC effect in recurrent aphthous ulceration.