PHENOTYPE AND SUPPRESSOR ACTIVITY OF T-LYMPHOCYTE CLONES EXTRACTED FROM LESIONS OF ORAL LICHEN-PLANUS

Lymphocytes were extracted from six biopsy specimens of oral lichen pl anus. T-lymphocyte lines were expanded in culture with phytohaemagglut inin and interleukin 2, and cloned by limiting dilution. Fifteen T-cel l clones were isolated with a probability of clonality of 96.3%. The m ajority of clones (n = 13) expressed the alpha beta T-cell receptor, a nd of these, 11 were CD8(+) and two were CD4(+). Two clones were CD4(- ) and CD8(-), and expressed the gamma delta T-cell receptor. The abili ty of these clones (effecters) to suppress concanavalin-A-stimulated p roliferation of autologous lesional T-cell lines (responders) was asse ssed. Maximum suppressor activity ranged from 17 to 100%. The majority of clones (n = 12), including a CD3(+)CD4(+)CD8(-)alpha beta(+) clone , displayed suppressor activity which was proportional to the effector to responder ratio. A CD3(+)CD4(+)CD8(-)alpha beta(+) clone and CD3()CD4(-)CD8(-)gamma delta(+) clone displayed substantial helper activit y at higher effector to responder ratios. These results demonstrate di fferential helper and suppressor activity of T-lymphocyte clones extra cted from oral lichen planus lesions. The balance between help and sup pression may be a fundamental determinant of immunological activity wi thin the lymphocytic infiltrate of oral lichen planus, and hence may d ictate the clinical behaviour of the disease.