Immunohistological evaluation of alopecia areata treated with squaric acid dibutylester (SADBE).

A total of 19 patients with alopecia areata volunteered for serial biopsies of the scalp skin during SADBE treatment. Regrowth of terminal hair was seen in 12 of the 19 patients on the side of the scalp treated with SADBE for a minimum of four months, but not on a control side treated with sodium lauryl sulphate (SLS). Immunocompetent cells were characterized with ANAE staining and monoclonal antibodies in biopsy specimen showing marked peribulbar and perivascular inflammatory cell infiltrates. Inflammatory cell subclasses were repeatedly evaluated during SADBE treatment. No specific alterations in lymphocyte subclasses and macrophages were seen in relation to the hair growth response. In immunofluorescent studies it was found that in patients with regrowth of hair, immunoglobulins, fibrin and complement, appeared in the hair bulb and along the basement membrane during the treatment. Results were negative in patients without regrowth of terminal hair and in SLS-treated skin. As we could not demonstrate that any cell-mediated mechanism was involved, we suggest that SADBE may induce terminal hair growth through as yet uncharacterized mediators.