Stimulation of lymphocyte transformation by tissue homogenates in recurrent oral ulceration.

Cultures were set up of white cells from patients with oral ulceration and from control subjects. The effects of saline extracts of foetal oral mucosa, liver, skin, colon, striated muscle and salivary gland on DNA synthesis by lymphocytes in the cultures were determined by measuring their uptake of [C] thymidine. The results showed stimulation by oral mucosa, and to a lesser degree by skin, almost exclusively in patients with recurrent aphthous ulcers; colon and salivary gland stimulated the lymphocytes of occasional individuals regardless of the type or presence of oral ulceration, and liver produced a similar effect, but stimulated lymphocytes in a higher proportion of patients with aphthous ulcers. Specific stimulation by oral mucosa was increased during phases of ulceration and diminished during remissions. It is suggested that lymphocyte transformation (indicated by [C]thymidine uptake) in patients with recurrent aphthous ulceration is the result of specific antigenic stimulation of a portion of the lymphocyte population following previous encounter with an oral mucosal antigen.