Alopecia areata has been reported to be accompanied by abnormal autoimmune dysfunction. We examined the expression of cutaneous lymphocyte-associated antigen (CLA), which is a skin-specific lymphocyte homing receptor, in the peripheral blood lymphocytes and skin of patients with alopecia areata. In the patients' peripheral blood, the percentage of CLA-positive CD4+ or CD8+ lymphocytes, was significantly higher than that of normal controls. The patients with severe or progressive alopecia areata showed a much higher CLA-positivity compared to patients recovering from the disease. A chronological study showed that the percentage of CLA-positive peripheral blood lymphocytes, CD4 + or CD8 + lymphocytes decreased in parallel with the patients' good clinical course. The CLA-positivity in peripheral blood lymphocytes, CD4+ or CD8+ lymphocytes of patients with alopecia areata who did not respond to oral corticosteroid therapy remained higher than in those who responded well to the treatment. In the affected scalp skin, many infiltrating lymphocytes around the hair follicles, which were CD4+ or CD8+ lymphocytes, expressed CLA. These findings suggest that the CLA-positivity correlates with clinical activity and that CLA-positive CD4+ or CD8+ lymphocytes may play an important role in alopecia areata.