Study of peripheral T-cell subpopulations and lymphocyte proliferation in different phases of evolution of alopecia areata.

The current hypothesis on the pathogenesis of alopecia areata is immunologically mediated, yet no conclusive data has been documented. To clarify the changes in various phases of disease evolution, analysis of T lymphocyte subpopulations was carried out in the peripheral blood of 34 patients and 27 healthy normal subjects by means of OKT-3, OKT-4, OKT-8 and Ia1 monoclonal antibodies. Study of lymphocyte proliferation in response to various mitogens was further carried out in 27 patients and 25 healthy normal subjects. Significant predominance (p less than 0.01) of OKT-8 positive (cytotoxic/suppressor) cells and diminution (p less than 0.01) of Ia1 positive cells were noted in the whole alopecia group and in various subgroups of disease evolution. Since diminution (p less than 0.05) of OKT-4 positive (inducer/helper) cells was also noted in the stable phase, it was postulated that these activated T cells migrated from circulation to the local site of primary event. Hence, it was evident that the predominance of cytotoxic/suppressor cells was a relative change, and the role of inducer/helper cells in the pathogenesis was implicated. No enhancement of lymphocyte proliferation was observed.