comparison of direct immunofluorescence of plucked hair and skin for evaluation of immunological remission in pemphigus

Background: Pemphigus is a chronic autoimmune bullous disorder characterized by autoantibodies directed against desmoglein 3 and/or 1. Demonstration of intercellular deposition of IgG on the cell surface of keratinocytes by direct immunofluorescence (DIF) of the skin is the gold standard in the diagnosis of pemphigus. Recently, DIF of plucked hair demonstrating intercellular deposition of IgG in the outer root sheath (ORS) has shown to be useful. Objective: To compare the DIF of plucked hair and skin for the evaluation of immunological remission in pemphigus vulgaris patients in clinical remission. Materials and Methods: A total of 30 patients with pemphigus vulgaris with positive DIF of the skin and hair at baseline were included, and DIF of skin and hair was repeated after 6 months or more of clinical remission (with no new/non-healing lesions). Presence of intercellular deposits of IgG and or C3 in skin and ORS of the hair was considered as positive. Results: Of the 30 patients, DIF of skin was positive in 10 patients and hair was positive 14 patients. The findings of hair and skin DIF correlated with each other in 22 patients. In 6 (20%) patients DIF of hair was positive even though the DIF of skin was negative. The sensitivity of hair DIF was 80% and specificity was 70%. Limitations: Small sample size. Conclusion: DIF of hair is a simple, non-invasive, and cost effective procedure and can be used as an additional procedure for the assessment of immunological remission in patients with pemphigus vulgaris.