CHARACTERIZATION OF ANTIMITOCHONDRIAL ANT IBODY TYPE-2 (ANTI-M2) - COMPARISON OF 2 METHODS, WESTERN BLOTTING AND INDIRECT IMMUNOFLUORESCENCE

About 94% of patients with typical features of primary biliary cirrhos is (PBC) have been shown to be anti-M2 positive. Today the relevance o f anti-M2 antibodies as a &agnostic marker of PBC is well established. The usual method of detection is by indirect immunofluorescence with cryostat sections of rat organs. In our laboratory we have developed a second identification technique for these antibodies: Western-blottin g. To compare immunofluorescence and immunoblotting results, we select ed sera from 252 patients: 142 sera from patients with documented PBC, 50 from patients with another hepatic disease, 10 from patients with haematological lupus and 50 from healthy blood donors. We characterize d antimitochondrial antibody M2 by the presence of one or more of five antigenic determinants : 65-70 kDa (a), 52-54 kDa (b), 44 kDa (c), 23 -26 kDa (d) and 16-20 kDa (e). This technique is especially useful as a backup method intention for identifying a very slight or atypical fl uorescence pattern.