In vivo delayed-type hypersensitivity in 109 patients with vitiligo.

Abstract

Although the etiology of the depigmentation disorder vitiligo is still not completely understood, many investigators believe that an autoimmune reaction may play a major role. In this regard, T-lymphocyte-mediated immunity has been implicated frequently in the pathogenesis of the disease. Most studies have applied in vitro testing of cell-mediated immunity, however, rather than in vivo measurements. Therefore, our study was undertaken to define the cutaneous delayed-type hypersensitivity (DTH) in vivo reaction in association with the absence/presence of serum thyroid autoantibodies, which are a good representative marker for autoimmunity in patients with vitiligo. DTH was evaluated in the normal pigmented skin of 109 vitiligo patients (29 men and 80 women) and in the depigmented skin of 27 of this group (5 men and 22 women) using the dermal application of seven common recall antigens together with a negative control. Individuals were considered to be hypoergic if the DTH sum score was </= 5 mm in women or </= 10 mm in men, or if they responded to only one or two antigens. The mean sum score was 10.2 +/- 8.4 with an average of 2.3 +/- 1.6 positive reactions in depigmented skin vs. a sum score of 12.4 +/- 9. 0 with an average number of 2.6 +/- 1.6 positive reactions in normal pigmented skin. There was no statistically significant difference between depigmented and normal pigmented skin using the paired t-test (P > 0.05). Further evaluation of these data showed no significant correlation between the presence of thyroid autoantibodies as well as selected clinical parameters and an aberration in cutaneous DTH. In contrast to earlier reports, our in vivo studies of cutaneous DTH reactions revealed no clinically significant aberrant cellular immunity in this patient group. These results indicate that the immune reaction in vitiligo may be only a secondary event in the pathogenesis of the disease.