title: Antimitochondrial antibody-negative primary biliary cirrhosis: a subset of primary biliary cirrhosis.
abstract: OBJECTIVE
  Antimitochondrial antibodies (AMA) are the hallmark in primary biliary cirrhosis (PBC); nevertheless, it has long been recognized that 5-10% patients with typical features compatible with PBC do not have detectable AMA, and they were referred to as 'AMA-negative PBC'. This study aimed to evaluate whether AMA-negative/positive PBC represents different clinical entities.
  
  
  METHODS
  We compared the clinical, laboratory, percentage of regulatory T cells (Tregs) in peripheral blood, liver biopsy features and response to treatment of the two groups of patients. The first group was comprised of 12 patients with 'AMA-negative PBC'. The second was made up of another 12 PBC patients with positive AMA.
  
  
  RESULTS
  Antimitochondrial antibodies-negative/positive patients were remarkably similar in terms of clinical manifestations, liver biochemistries and histological findings. The frequency of anti-nuclear antibodies, anti-smooth-muscle antibody, anti-gp210 and anti-sp100 antibody showed no significant difference between the two groups. A significantly lower mean percentage of CD4+CD25(high) T cells was observed in peripheral blood mononuclear cells of AMA-negative/positive PBC patients compared with that of the 12 control subjects (5.8+/-1.8 and 5.4+/-1.4% vs. 7.6+/-1.7% respectively; P=0.014 and 0.004). However, no difference could be found between AMA-negative and AMA-positive PBC patients (P=0.599). After 1 year treatment with ursodeoxycholic acid, the two groups showed similar response.
  
  
  CONCLUSIONS
  Antimitochondrial antibody-negative/positive PBC patients are similar in clinical, laboratory, percentage of Treg in peripheral blood, liver biopsy features and response to treatment. This suggests that AMA-negative PBC may be a variant of AMA-positive PBC rather than a separate clinical entity.
authors.affiliation: Department of Rheumatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Xu Hua
authors.initials: XH
authors.lastname: Shi
authors.forename: Feng Chun
authors.initials: FC
authors.lastname: Zhang
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Li Xia
authors.initials: LX
authors.lastname: Gao
mesh_terms: D001323:Autoantibodies / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D015151:Immunoblotting; D008105:Liver Cirrhosis, Biliary / Q000145:classification* / Q000188:drug therapy / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000276:immunology*; D018709:Statistics, Nonparametric; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014580:Ursodeoxycholic Acid / Q000627:therapeutic use*
chemical_list: D001323:Autoantibodies; D014580:Ursodeoxycholic Acid