SKIN EXPLANT CULTURE - A RELIABLE METHOD FOR DETECTING PEMPHIGOID ANTIBODIES IN PEMPHIGOID SERA THAT ARE NEGATIVE BY STANDARD IMMUNOFLUORESCENCE AND IMMUNOBLOTTING

We investigated the presence of bullous pemphigoid antibodies in bullo us pemphigoid sera that are negative by standard indirect immunofluore scence. We incubated each of four indirect immunofluorescence-positive bullous pemphigoid sera, seven indirect immunofluorescence-negative b ullous pemphigoid sera, one indirect immunofluorescence-negative herpe s gestationis serum, three indirect immunofluorescence-positive epider molysis bullosa acquisita sera, five indirect immunofluorescence-negat ive epidermolysis bullosa acquisita sera, and two normal human sera wi th fresh human skin explants in medium 199 at 4-degrees-C for 48 h. Al l bullous pemphigoid sera, herpes gestationis serum, and the three ind irect immunofluorescence-positive epidermolysis bullosa acquisita sera had IgG that bound the basement membrane zone of skin explants with m oderate to marked intensity as demonstrated by immunofluorescence. Nor mal sera and indirect immunofluorescence-negative epidermolysis bullos a acquisita sera failed to bind the explant basement membrane zone. Im munoblotting of bullous pemphigoid sera showed five of seven indirect immunofluorescence-negative bullous pemphigoid sera to bind high-molec ular weight and/or low-molecular weight bullous pemphigoid antigens fr om epidermal extracts. We conclude that the skin explant culture syste m is a very sensitive method for the detection of bullous pemphigoid a ntibodies in all bullous pemphigoid sera.