A STUDY OF ANTIMITOCHONDRIAL ANTIBODIES IN A RANDOM-POPULATION IN ESTONIA

Primary biliary cirrhosis (PBC) is an autoimmune liver disease charact erized by the spontaneous destruction of the small intrahepatic bile d ucts. The hallmark serologic feature of PBC is the presence of high-ti ter antimitochondrial antibodies (AMA). Both the incidence and prevale nce of PBC varies geographically; epidemiological data may provide val uable insight regarding the pathogenic mechanisms and etiology of dise ase. Thus far, the majority of studies on the occurrence of PBC and AM As have been derived from autopsy, mortality figures, or hospital admi ssion records. The numbers reported reflect only those patients with c linical disease. To address this issue, an adult population sample rep resenting all age groups in the village of Karksi-Nuia in southern Est onia was selected for a study of AMA incidence, This village has uniqu e features that make it ideal for such a study. First, the village is remote and a substantial number of families have lived in the area for generations, There is also a limited influx of new families into the village, therefore providing a limited genetic repertoire. In this uns elected adult population, we examined AMA incidence by both immunoblot and ELISA, using native and recombinant antigens. Of the 1461 people studied, 13 (0.89%) were AMA positive. A similar frequency (0.96%) was found among 104 persons from a neighboring village, who subsequently joined the study. Our study suggests that the presence of AMA in Eston ia is in agreement with the reported incidence of less than 1% AMA in a mixed hospital population.