IgM-dependent bullous pemphigoid

IgM-dependent bullous pemphigoid (BP) is a rare autoimmune bullous dermatosis with polymorphic clinical manifestations and has been the subject of scientific debate in recent years. So far, there is no consensus on the target antigens, diagnostic features and therapeutic approaches in this pathology. Some authors consider the presence of IgM antibodies in the basal membrane of the epidermis as the prodromal stage of BP, others — as an independent disease. Several studies have emphasized the persistent course of IgM-dependent BP and the need for special therapeutic approaches to achieve a sustained remission in patients. We present the results of retrospective analysis of 345 skin biopsies obtained from 345 patients who were examined in the dermatovenereological department of the M.F. Vladimirsky Moscow Regional Research and Clinical Institute using direct immunofluorescence method. In addition, we describe 2 clinical cases of IgM-dependent BP. Objective. To study the incidence and immunomorphological features of IgM-dependent BP. Results. IgM-dependent BP has been detected in 2 (0.5%) cases. In one case, U-dentate fixation of IgM and complement component 3 (C3) has been revealed in the area of the basal membrane of the epidermis, in another — linear fixation of IgM and C4d fragment. No significant differences in the disease’s course and therapeutic approaches have been noted, remission occurred after application of standard therapy. Conclusion. IgM-dependent BP is a rare disease. Fixation of IgM in the basal membrane area can be a manifestation of both a specific variant of BP and an independent dermatosis. Further research is needed to make final conclusions about the nature of presented disease.