Sensitivity of indirect immunofluorescence and immunoblotting for the detection of intercellular antibodies in endemic pemphigus foliaceus (fogo selvagem)

Background Two assays are available to detect anti-skin antibodies in patie nts with fogo selvagem (FS): indirect immunofluorescence (IIF) and immunobl otting (IB). This study was conducted to compare the sensitivity of these a ssays in detecting FS antibodies. Design Eighty-nine serum samples of 48 patients with FS and control serum f rom 15 normal individuals were tested concurrently for the presence of FS a ntibodies by IIF and IB. IIF studies were conducted using four different su bstrates: human skin, monkey and guinea pig esophagus, and bovine tongue. Results FS antibodies were detected much more commonly by IIF than by IB, i .e. in 71% vs. 28% of serum samples respectively. By IIF, the antibodies re acted most strongly against human skin. Conclusions IIF is a more sensitive assay than IB for detecting antibodies associated with FS. The sensitivity of the test is maximized by using human skin as a substrate.