Complement as an essential factor for indirect immunofluorescence in cases of pemphigoid

Abstract

Hitherto in the literature no proof has been published of a complement activation on the basement membrane in cases of pemphigoid. In this paper, for the first time, it is demonstrated, even if only in vitro, that complement, whose presence in the region of the basement membrane has long been known, plays an active role in a reaction. Through the action of the haemolytic system (amboceptor and sheep erythrocytes) and of anti C3 on reaction specimens for indirect immunofluorescence in pemphigoid, it is shown that the indicator reaction of the fluorescein-labelled anti-IgG with the immune complex attached to the basement membrane is markedly dependent on complement. Free, dissolved IgG is precipitated by appropriate anti-serum, even without complement.