Relationship of β1H globulin and cleavage fragments of the third component of complement in the skin of patients with bullous pemphigoid and dermatitis herpetiformis

Abstract

In this report, the skin from patients with bullous pemphigoid (BP) and dermatitis herpetiformis (DH) was stained with fluorochromized antisera to the C3 cleavage fragments, C3c and C3d and the C3b control protein, β1H, so as to study the catabolism of C3 in BP and DH, C3d was the most frequently found product in both BP and DH. Deposits of C3c were frequently found together with deposits of β1H in BP but not in DH. Deposits of β1H suggest the presence of C3b and/or C3bi since in vitro model systems have shown that β1H binds to C3b and C3bi but not to native C3 or C3d. Additionally, when the basement membrane zone (BMZ) of normal human skin was treated with anti-cutaneous basement membrane zone antibody and fresh serum as a source of complement it stained with the anti-C3c, anti-C3d, and anti-β1H reagents. Upon exposure to C3bINA, β1H, and leukocyte elastase the normal skin stained only with anti-C3d. Together these findings suggest that the in vivo catabolism of C3 is similar to that observed in in vitro model systems.