[Significance of antimitochondrial antibodies. In a population of 111 patients from the Midi-Pyrenees region].

The aetiological significance of antimitochondrial antibodies (anti-M) being debated, we conducted an aetiological study of 111 sera with anti-M2 antibodies from patients living in the Midi-Pyrénées region (South-West France); these anti-M2 antibodies had been detected in the years 1984-85. Fifty-nine percent of the patients had primary biliary cirrhosis (41 p. 100 were asymptomatic, and 6 p. 100 had normal liver function tests). Anti-M2 antibodies at a titer of 1/500 or more were significantly more frequent among these patients as compared with the others (P less than 0.001, probability = 0.73). Six percent of the patients had chronic active hepatitis. The incidence of primary biliary cirrhosis could be estimated at 8.5 per 10(6) people per annum. In this patient population, primary biliary cirrhosis was more common than all other causes of anti-M2 antibodies, and an anti-M2 titer of 1/500 or more had a 73 p. 100 predictive value for that disease. In the region concerned the incidence of primary biliary disease was higher than previously reported in Western Europe.