Increased HLA-DR+ T-lymphocyte population in peripheral blood of alopecia areata.

The populations of activated T-cell subsets [HLA-DR(+)-Leu 4+ cells, interleukin 2 receptor positive (IL-2R+)-Leu 4+ cells] in the peripheral blood of patients with alopecia areata (AA) were investigated using double direct immunofluorescence staining. Fifty-eight patients with AA were classified into one of three types: those with inactive single AA (type 1) lesions, active multiple alopecia areata (MAA) lesions and active alopecia totalis (AT) (type 2) and chronic alopecia universalis (AU) (type 3). Compared to normal controls, high percentages of HLA-DR(+)-Leu4+ cells were detected in types 2 and 3 AA patients, but not in type 1 AA patients. These findings suggest that T cells are activated in the peripheral blood of active MAA, AT and chronic AU.