Given the task definition and input, reply with output. Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Codification of variant forms between Primary Biliary Cirrhosis (PBC) and Autoimmune Hepatitis (AIH) has not been definitively standardized. The aim of this study was to compare among 102 consecutive patients, 2 subsets of overlap syndrome (OS, N=21) with and without antimitochondrial antibody (AMA) to two groups of patients with typical PBC (N=43) or AIH (N=38).', 'OS was defined by the presence in the same patient of at least 2 of 3 accepted criteria of PBC and AIH. Twelve patients with OS were AMA negative and 9 were AMA positive.', 'A lower level of alanine transaminase (139+/-48 vs 269+/-154 IU/L, P<0.05) and a trend towards a higher level of alkaline phosphatase or gamma-glutamyl transpeptidase was observed in OS without AMA than in OS with AMA (693+/-200 vs 544+/-124 IU/L; 370+/-66 vs 241+/-77 IU/L, respectively). All AMA-negative patients with OS had antinuclear and/or anti-smooth muscle antibodies. OS without AMA differed from those with AMA in that they had more severe bile duct damage including destructive cholangitis (P<0.05), ductopenia (P<0.05), ductular hyperplasia (P<0.05) and a higher METAVIR fibrosis score (2.5+/-0.3 vs 1.3+/-0.3, P<0.05). The response to therapy was not different between PBC, AIH and OS.
Answer: According to the presence of AMA, 2 homogeneous subgroups of patients with overlap syndrome between PBC and AIH may be identified. AMA status affects clinical presentation and liver disease severity of OS.
Do characterization of overlap syndrome between primary biliary cirrhosis and autoimmune hepatitis according to antimitochondrial antibodies status?