title: Quantitative analysis of IgM anti-HBc in chronic hepatitis B patients using a new "gray-zone" for the evaluation of "borderline" values.
abstract: METHODS
  In order to define the clinical significance of borderline levels of IgM anti-HBc in chronic hepatitis B patients, we followed up 89 untreated hepatitis B patients (19 HBeAg pos and 70 anti-HBe pos) for 1 year, with monthly monitoring of IgM anti-HBc using a highly sensitive quantitative microparticle enzyme immunoassay (IMx CORE-M, Abbott). As a control group we used 304 healthy subjects: 150 HBsAg negative and anti-HBc/anti-HBs positive, and 154 without markers of HBV infection. The statistical analysis performed by Receiver Operating Characteristic curve indicated the 100% sensitivity cut-off at 0.081 IMx index and 100% specificity cut-off at 0.358 IMx index.
  
  
  RESULTS
  We could define the range of a chronic hepatitis B "gray-zone" between 0.100 [80.6% specificity (95% CI, 76.2%-85%), 96.6% sensitivity (95% CI, 92.8%-100%)] and 0.200 [95.7% specificity (95% CI, 93.4%-98%) and 78.7% sensitivity (95% CI, 70.2%-87.2%)] of the IgM anti-HBc-IMx index. In fact, none of the chronic hepatitis B patients had IgM anti-HBc-IMx values persistently below 0.100 during the follow-up, whereas 57.3% had values persistently higher than 0.200. In 38.2%, IgM anti-HBc values occasionally fell within the "gray-zone" limits. In the remaining four patients (4.4%), the results overlapped the "gray-zone" values.
  
  
  CONCLUSIONS
  These results suggest that the use of a chronic hepatitis B "gray-zone" for values of quantitative IgM anti-HBc assays helps to distinguish "true healthy carriers" from asymptomatic chronic anti-HBe positive hepatitis B patients who have been shown to have temporary remissions of liver disease and frequently undetectable serum HBV-DNA.
authors.affiliation: Department of Internal Medicine, Bolognini Hospital, Seriate, Bergamo, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Colloredo
authors.forename: G
authors.initials: G
authors.lastname: Bellati
authors.forename: G
authors.initials: G
authors.lastname: Leandro
authors.forename: P
authors.initials: P
authors.lastname: Colombatto
authors.forename: A
authors.initials: A
authors.lastname: Rho
authors.forename: F
authors.initials: F
authors.lastname: Bissoli
authors.forename: M R
authors.initials: MR
authors.lastname: Brunetto
authors.forename: G
authors.initials: G
authors.lastname: Angeli
authors.forename: G
authors.initials: G
authors.lastname: Ideo
authors.forename: F
authors.initials: F
authors.lastname: Bonino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002908:Chronic Disease; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000276:immunology*; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012074:Remission Induction; D012680:Sensitivity and Specificity
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D007075:Immunoglobulin M