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

Abstract Background Two assays are available to detect anti-skin antibodies in patients with fogo selvagem (FS): indirect immunofluorescence (IIF) and immunoblotting (IB). This study was conducted to compare the sensitivity of these assays in detecting FS antibodies. Design Eighty-nine serum samples of 48 patients with FS and control serum from 15 normal individuals were tested concurrently for the presence of FS antibodies by IIF and IB. IIF studies were conducted using four different substrates: 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 reacted 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. [ABSTRACT FROM AUTHOR]