Classical and Alternate Pathway Activation of Complement in Pemphigus Vulgaris Lesions

Early oral and skin lesions from 6 patients with pemphigus vulgaris were examined for the presence of C1Q, C3, C3 proactivator (C3PA), and properdin, in addition to immunoglobulins (IgG, IgA, and IgM), using immunofluorescent techniques. IgG was deposited in the intercellular substance in both normal appearing areas of the lesions and pathologic areas of the lesions C1q, C3, and C3Pa, on the other hand, were deposited only an pathologic areas where acambolysis was evident. Properdin deposits were evident in 2 lesions only, and then only around individual acantholytic cells. IgA localization was seen in intercellular substance areas only in oral lesions. These studies further implicate the complement system in the pathogenesis of pemphigus vulgaris