title: The putative protective role of hepatitis B virus (HBV) infection from autoimmune disorders.
abstract: BACKGROUND
  The etiology of autoimmune diseases is not fully clarified and the mechanisms underlying their initiation and progression are still obscure. It is becoming clear that in a genetic susceptible individual an environmental trigger such as infectious agent in general and viruses in particular could initiate the development of an autoimmune disease. Hepatitis B virus (HBV) is notorious in its association with diverse autoimmune diseases. Therefore, we aimed to determine the presence of hepatitis B core antibody (HBcAb), a seromarker for past or present infection with HBV, in a large number of sera collected from patients with different autoimmune diseases.
  
  
  METHODS
  A cohort of 675 sera samples of 5 different autoimmune diseases and healthy donors were screened for evidence of a prior infection with HBV. All samples were tested for hepatitis B core antibody (IgG) using the Monolisa anti-HBc PLUS commercial kit (Bio-Rad, Hercules, San Francisco, USA).
  
  
  RESULTS
  Lower percentage of HBcAb was found in sera of the autoimmune diseases when compared to normal controls. Fifteen (10.7%) from 140 normal controls were found positive for the presence of HBcAb. Two (2%) out of 98 multiple sclerosis (MS) sera were positive for the presence of HBcAb (OR: 0.17, 95%CI: 0.03-0.77, p=0.01), 3 (2.5%) out of 117 systemic lupus erythematosus (SLE) sera (OR: 0.2, 95%CI: 0.06-0.77, p=0.01), 4 (4.5%) out of 89 type 1 diabetes (T1D), 5 (6.1%) from 82 Sjogren's syndrome (SS) sera and 12 (8%) from 149 rheumatoid arthritis (RA) sera were positive for the presence of HBcAb.
  
  
  CONCLUSIONS
  Our data divulge an unexpected low percentage of antibodies to HBcAg in patients with SLE, MS and T1D in comparison to healthy matched donors. This finding may raise a protective role to HBV in some autoimmune diseases i.e. hygiene theory.
authors.affiliation: Center for Autoimmune Diseases, Department of Medicine 'B', Sheba Medical Center, Israel.
authors.forename: Maya
authors.initials: M
authors.lastname: Ram
authors.forename: Juan-Manuel
authors.initials: JM
authors.lastname: Anaya
authors.forename: Ori
authors.initials: O
authors.lastname: Barzilai
authors.forename: David
authors.initials: D
authors.lastname: Izhaky
authors.forename: Bat-Sheva
authors.initials: BS
authors.lastname: Porat Katz
authors.forename: Miri
authors.initials: M
authors.lastname: Blank
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Shoenfeld
mesh_terms: D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology / Q000517:prevention & control* / Q000821:virology*; D006509:Hepatitis B / Q000097:blood / Q000276:immunology*; D006510:Hepatitis B Antibodies / Q000097:blood; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans
chemical_list: D006510:Hepatitis B Antibodies