Long-term interferon-alpha therapy induces autoantibodies against epidermis

Background: While interferon (IFN) is known for its immunoregulatory properties, it has also been shown to induce autoimmune disorders such as lupus erythematosus, hypothyroidism, antiphospholipid syndrome and, recently, bullous pemphigus-like eruptions. Objective: The purpose of this study was to determine the percentage of antibodies against epidermis induced by IFN-alpha therapy, as detected by indirect immunofluorescence and Western blotting (WE). Method: We have studied the sera of 47 patients treated with low doses of IFN-alpha 2a for malignant melanoma or cutaneous T cell lymphoma for a period of 12 months. These sera were tested by standard IIF and WE. Results: 32% of patient sera were positive after 6 months of treatment. Antibodies against epidermis were most often of the pemphigus type as confirmed by WE. Two types of labeling were noted for anti-basement membrane antibodies: basal cytoplasmic pattern in 4 sera and along the dermal side of the basal keratinocytes in 2 sera, Conclusion: This study brings biological arguments to confirm the direct role of IFN-alpha in the development of pemphigus-like eruption, and emphasizes the need for clinical follow-up of patients treated with IFN-alpha over a long period of time.