Sensitivity of indirect immunofluorescence and ELISA in detecting intercellular antibodies in endemic pemphigus foliaceus (Fogo Selvagem).

ABSTRACT

BACKGROUND: Since 1967 dermatology has used the classic technique of indirect immunofluorescence (IFI) for the detection of autoantibodies against antigens of the skin in diseased people with endemic pemphigus foliaceus. Thirty years later enzyme-linked immunosorbent assays--ELISA (rDsg1 and rDsg3) appeared as a viable option. A group of highly recognized researchers have concluded that ELISA is a simple, sensitive and highly specific method, allowing for diagnostic differentiation between pemphigus vulgaris (PV) and endemic pemphigus foliaceus (EPF). Scientific literature certifies that both ELISA and IIF bear high sensitivity in spite of the fact that a direct comparison between the ELISA and IIF tests has never been performed. OBJECTIVES: This study was conducted to compare the sensitivity of these tests in detecting antibodies in the EPF. MATERIAL AND METHODS: Thirty-two serum samples were collected from patients with EPF. The control serum of 15 healthy individuals was tested to detect the presence of antibodies of EPF by indirect immunofluorescence and ELISA (rDsg1 and rDsg3). The IIF was performed, taking human skin as a substrate. RESULTS: Antibodies in patients with EPF were detected more commonly by the ELISA (rDsg1) (91%) compared with IIF (81%). CONCLUSIONS: The ELISA (rDsg1) is slightly more sensitive than IIF in detecting antibodies related to EPV. However, according to our results, we do not currently possess a test with 100% accuracy in differentiating EPF from PV. Although previous studies have associated Dsg3 with PV, the tests performed during this study showed that 12% (4/32) of patients with EPF (cutaneous diseases only) also had Dsg3 antibodies.