Detection of autoantibodies against bullous pemphigoid and pemphigus antigens by an enzyme-linked immunosorbent assay using the bacterial recombinant proteins.

To develop a new method to evaluate autoantibodies in various autoimmune bullous skin diseases, we examined reactivity of bullous pemphigoid (BP) and pemphigus vulgaris (PV) patients' sera with partial bacterial fusion proteins of the 230 kD BP antigen (BPAG1) and PV antigen, respectively, by an enzyme-linked immunosorbent assay (ELISA), and compared the results with those of immunoblotting. We used two fusion proteins derived from the mouse BPAG1 and a fusion protein derived from the amino-terminus (EC1-2) of PV antigen. For both BP and PV sera, the ELISA scores were well correlated with the reactivities on immunoblot assays. The present study indicates that ELISA using recombinant antigen proteins in various autoimmune bullous skin diseases will be a new useful technique to detect the autoantibodies. However, development of recombinant proteins with the entire molecule and correct conformation will be necessary to establish a perfect ELISA system in the future.