T-CELL RECEPTOR V-GENE USAGE IN ORAL LICHEN-PLANUS - INCREASED FREQUENCY OF T-CELL RECEPTORS EXPRESSING V-ALPHA-2 AND V-BETA-3

In order to analyse the clonality of T cells in the inflammatory infil trate of oral lichen planus (OLP), mucosal biopsies were obtained from seven patients with manifest disease. The biopsies were stained with MoAbs directed against 11 different T cell receptor (TCR) V-gene famil ies, anti-CD4, anti-CD8 and IL-2 receptor (IL-2R). For comparison, the frequencies of the different TCR V-families were determined in biopsi es from five patients with oral candidosis as well as in peripheral bl ood from three patients with OLP and from six healthy blood donors (HB D). The occurrence of the investigated TCR V-families varied between 0 % and 7% in venous blood obtained from both HBD and OLP patients. T ly mphocytes expressing the TCR V beta 3 and V alpha 2 in OLP biopsies we re, however, detected in frequencies ranging between 18% and 40% of th e total fraction of lymphocytes, a consistent finding for all the OLP infiltrates studied. The other nine TCR V-families examined appeared i n low frequencies both in biopsies and in peripheral blood. V alpha 2( +) and V beta 3(+) cells were often localized adjacent to the basal me mbrane. In contrast, T cells in Candida-induced lesions did not expres s a biased TCR distribution, and most V-families studied appeared in f requencies of 0-6%. Thus, T lymphocytes in OLP lesions express a subst antially higher frequency of TCR V alpha 2 and V beta 3 than expected from the distribution in blood. The clonal expansion of T cells observ ed in OLP suggests that a superantigen is involved in the pathogenesis of the disease. Whether this superantigen is of exogenous or endogeno us origin needs to be investigated.