AIM: To evaluate the serum concentration of antimitochondrial antibodies (AMAs) as a prognostic indicator of progressive primary biliary cirrhosis (pPBC). METHODS: Serum concentrations of AMA subtypes (anti-M2, anti-M4, and anti-M9), biochemical indices of liver function and Mayo risk factor (MRF) were determined in 30 women with diagnosed primary biliary cirrhosis (PBC) selected among 348 females with elevated alkaline phosphatase but without signs of hepatic decompensation. They were followed up for 5 years for possible development of hepatic decompensation. RESULTS: Anti-M2 concentration was significantly correlated with bilirubin and albumin levels as well as MRF, whereas anti-M4 was significantly correlated with albumin level, prothrombin time and MRF. During the 5-year follow-up, progressive PBC (pPBC) was diagnosed in 3 among 23 patients available for evaluation. These 3 patients were positive for both anti-M2 and anti-M4. Anti-M2 serum concentration exceeded 1 300 RU/mL in patients with pPBC and only in 1 among 20 non-progressive PBC persons (5%). Anti-M4 serum concentration exceeded 400 RU/mL in 2 of the progressive patients and none in the non-progressive group. In contrast, anti-M9 serum concentration was below 100 RU/mL in all patients with pPBC, and higher than 100 RU/mL in 11 women (55%) among the non-progressive group. CONCLUSION: Females with elevated alkaline phosphatase and high anti-M2 and anti-M4 concentrations are at a high risk for developing pPBC. Quantitative AMA detection should be considered as a method for early diagnosis of pPBC. AIM: To evaluate the serum concentration of antimitochondrial antibodies (AMAs) as a prognostic indicator of progressive primary biliary cirrhosis (pPBC). METHODS: Serum concentrations of AMA subtypes (anti-M2, anti-M4, and anti-M9) of liver function and Mayo risk factor (MRF) were determined in 30 women with diagnosed primary biliary cirrhosis (PBC) selected among 348 females with elevated alkaline phosphatase but without signs of hepatic decompensation. They were followed up for 5 years for possible development of hepatic decompensation. RESULTS: Anti-M2 concentration was significantly correlated with bilirubin and albumin levels as well as MRF, where anti-M4 was significantly correlated with albumin level, prothrombin time and MRF. During the 5-year follow-up, progressive PBC ) was diagnosed in 3 among 23 patients available for evaluation. These 3 patients were positive for both anti-M2 and anti-M4. Anti-M2 serum concentration exceeded 1 300 RU / mL in pati Anti-M4 serum concentration exceeded 400 RU / mL in 2 of the progressive patients and none in the non-progressive group. In contrast, anti-M9 CONCLUSION: Females with higher alkaline phosphatase and high anti-M2 and anti- M4 concentrations are at a high risk for developing pPBC. Quantitative AMA detection should be considered as a method for early diagnosis of pPBC.