[The results of phylogenetic and experimental research into the etiology of pemphigus vulgaris].

An antigen, binding with antibodies from patients with pemphigus vulgaris, has been found in the epidermis of a shedding Natrix natrix. This permitted a hypothesis on the atavistic nature of pemphigus, consisting in the following: abolition of tolerance to pemphigus antigen (PA) in humans and mammals is explained by the release of the 'shedding' atavistic gene, that codes for the humoral factor responsible for PA expression in keratinocytes. This hypothesis has been confirmed by experimental induction of pemphigus-like changes of the serpentine and murine epidermis (by subcutaneous injections of a shedding snake serum protein--SSSP), as well as by experiments with SSSP blocking of pemphigus induced by passive transfer of antibodies from patients with pemphigus vulgaris to newborn BALB/s mice.