title: Autoimmune hepatitis type 2 associated with an unexpected and transient presence of primary biliary cirrhosis-specific antimitochondrial antibodies: a case study and review of the literature.
abstract: BACKGROUND
  Unlike other autoimmune liver diseases, primary biliary cirrhosis (PBC) has never been reported in early childhood, while type 2 autoimmune hepatitis (AIH) is eminently a paediatric disease.
  
  
  METHODS
  We describe a case of type 2 AIH with serological positivity for PBC-specific anti-mitochondrial antibodies (AMA) in a 3-year old girl. We found this observation intriguing as AMA and indeed an overlap with PBC are virtually absent in Type 2 AIH, a pediatric form of AIH which is distinct precisely because it is characterized by pathognomonic anti-liver kidney microsomal type 1 (LKM-1) showing a remarkable antigen-specificity directed against cytochrome P4502D6. We also review the literature in relation to AMA positivity in paediatric age and adolescence. In our case, the presence of AIH-2-specific anti-LKM-1 and PBC-specific AMA was confirmed by indirect immunofluorescence (IIF), and immunoblotting and ELISA based on recombinant mitochondrial antigens. The clinical, laboratory and histological features of the child are given in detail. Interestingly the mother was AMA positive without other features of PBC. The child was successfully treated with immunosuppression and five years after the original diagnosis is on a low dose of prednisolone and azathioprine, with no signs of relapse. Anti-LKM-1 antibodies are still present in low titres. AMA were detectable for the first 4 years after the diagnosis and disappeared later.
  
  
  CONCLUSIONS
  This is the first case report in the literature of AIH type 2 with an unexpected PBC-specific AMA positivity in a young child. Response to immunosuppressive treatment was satisfactory and similar to that described in AIH. A review of published reports on AMA positivity in paediatric age shows that the antibody may arise in the context of immunodeficiency and is variably associated with liver damage.
authors: Center for Autoimmune Liver Diseases, Humanitas Clinical and Research Center, Via Manzoni 56, 20089, Rozzano(MI), Italy. pietro.invernizzi@humanitas.it
authors: Pietro
authors: P
authors: Invernizzi
authors: Maria Grazia
authors: MG
authors: Alessio
authors: Daniel S
authors: DS
authors: Smyk
authors: Ana
authors: A
authors: Lleo
authors: Aurelio
authors: A
authors: Sonzogni
authors: Luca
authors: L
authors: Fabris
authors: Manila
authors: M
authors: Candusso
authors: Dimitrios P
authors: DP
authors: Bogdanos
authors: Raffaele
authors: R
authors: Iorio
authors: Giuliano
authors: G
authors: Torre
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D001379:Azathioprine / Q000627:therapeutic use; D002675:Child, Preschool; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D019693:Hepatitis, Autoimmune / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008105:Liver Cirrhosis, Biliary / Q000276:immunology*; D008930:Mitochondria, Liver / Q000276:immunology*; D011239:Prednisolone / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D000888:Antibodies, Anti-Idiotypic; D005938:Glucocorticoids; D007166:Immunosuppressive Agents; D011239:Prednisolone; D001379:Azathioprine