Gastroenterology and Hepatology from Bed to Bench

Abstract

Indirect immunofluorescence on HEp-2 cell-line (HEp-2-IIF) remains the “gold standard” method for detection of antinuclear antibodies (ANA) (1). ANA is an operative definition, showing the possibility of autoantibodies (Aab) to bind nucleus and cytoplasmic antigen. One of the major examples is represent by anti-mitochondrial antibodies (AMA), which target proteins of the inner and outer mitochondrial membranes, located in the cytoplasm. In routinely lab-life the AC-21 pattern and the presence of related AMA can be confirm by commercial line-immunoblotting, ELISA, CLIA/FEIA assays and the standard IIF on rodent kidney/stomach/liver tissue sections. Several studies showed the use of other commercial assays and home made tests to detect AMA as immunoprecipitation and immunoblotting. However the use of IP or IP-WB in a routinely laboratory is difficult to apply, because of numerous cases to process and the related troubles.

The routinely lab experience also teach that commercial kits can not always detected and define specific AMA. Where find confirmation of AC-21 pattern if line-immunoblot and other routinely methods (ELISA, CLIA/FEIA assays) fail? We review AC-21 AMA-like sera from our patinets (year 2022) and purpose a revised diagnostic algorithm based on the combined use of IIF on Hep-2 cells, line immunoblot and IIF on rodent tissue as third line method. We showed that the use of IFI on rodent tissues became diriment to confirm AMAs presence, expecially when second level assay failed.