Direct T-cell effects of minoxidii

Minoxidil has been shown to induce hair regrowth in alopecia areata^1-4 by mechanisms that remain largely unknown. Alopecia areata is histologically characterized by miniaturized follicles with varying degrees of degeneration⁵ and by a dense perifollicular infiltration of T lymphocytes (helper, suppressor, and activated), Langerhans cells, and monocytes.^6,7 T lymphocytes appear to be the predominant cell type in the perifollicular infiltrates and, by implication, may be of pathogenic significance in the hair loss process. Changes in perifollicular T-cell and activated T-cell populations have been found after treatment with minoxidil.⁷ Responders to topical 5% minoxidil treatment (ie, those patients who had terminal hair regrowth) have shown decreases in tissue T cells and simultaneous increases in peripheral blood T cells.⁷.