[Assembly of the membrane attack complex of complement in pemphigus vulgaris skin]

The time course of the deposition of the membrane attack complex of complement (MAC) in the skin of a case of pemphigus vulgaris was studied by immunofluorescence technique using monoclonal antibodies to human C5, C6, C7, C8, C9 and C5b-9 neoantigens. Biopsy specimens of skin lesions always contained the MAC-related antigens in the ICS areas. No MAC could be detected in the non-lesional skin. It was also noted that MAC could be generated in vitro on cryostat-sectioned normal human skin by the patient serum in the presence of complement. The titer of this complement-fixing antibody rose during the clinically active phase. Results of these studies suggest that complement activation, with subsequent assembly of MAC, may be related to acantholysis in the pemphigus skin.