FC-18   A TRICHOLOGIST’S VIEW OF DIRECT IMMUNOFLUORESCENCE IN PEMPHIGUS

RM Trüeb, L Schaerer. Department of Dermatology, University Hospital of Zurich, Switzerland.

Pemphigus vulgaris and foliaceus are blistering diseases of the skin and mucous membranes caused by autoantibodies directed against the desmosomal glycoproteins desmoglein 1 and 3 (Dsg1/3), resulting in loss of keratinocyte cell to cell adhesion. Histological features are intraepidermal acantholytic blister formation with acantholysis extending down the outer root sheaths (ORS) of hair follicles. Since immunodeposits should also be demonstrable in the ORS of plucked hair, our aim was to verify the practicability of direct immunofluorescence (DIF) on plucked hairs of pemphigus patients. Of 21 pemphigus patients hairs were obtained as for a trichogram. The hairs were then shock-frozen and processed in the same manner as skin biopsies for DIF. The fluorescence microscopy examination was performed in a blinded manner. Simultaneously ELISA studies for determining anti-Dsg1 and -Dsg3 levels were performed on all patients’ sera. We were able to demonstrate a distinct pemphigus specific immunofluorescence pattern in the ORS of plucked anagen hairs as well as positive ELISA results in all patients, while controls (22 cases of bullous pemphigoid) were negative. Of 15 pemphigus patients in whom DIF of perilesional skin biopsy was performed, 14 were positive, while IIF demonstrated circulating pemphigus antibodies in 8 of 21 sera. These findings demonstrate the practicability of DIF on plucked hairs for diagnosing pemphigus. The method proved to be as sensitive as DIF of skin biopsy, and reached the level of sensitivity and specificity of ELISA. Since it has been suggested that a negative DIF of skin biopsy is an indicator of disease remission and helpful in determining when immunosuppressive therapy of pemphigus can be discontinued, DIF of ORS were followed up over 2 years in 15 patients. In a single patient in whom DIF of ORS turned negative, cessation of therapy was possible without relapse, while patients with positive DIF of ORS tended to relapse upon tapering of immunosuppressive therapy. We conclude that DIF of ORS of plucked hair is a reliable method that is easy to perform for diagnosing pemphigus, and that a negative DIF of ORS in the course of disease may serve as indicator of disease remission.