title: [Analysis of clinical characteristics and S gene mutation of hepatitis B virus (HBV) in patients with hepatitis B surface antigen RIA negative and HBV DNA positive].
abstract: BACKGROUND
  We investigated hepatitis B virus (HBV) infection cases, who were HBsAg negative by radioimmunoassay (RIA) and HBV DNA positive for their clinical characteristics, the S gene mutation of hepatitis B virus (HBV), and usefulness of other HBsAg immunoassay.
  
  
  METHODS
  Among the patients requested for HBV DNA quantification, 16 patients positive in HBV DNA but negative in HBsAg RIA (BNIBT HBsAg Kit, China) were enrolled. The "a" determinant of HBV S gene was sequenced and clinical characteristics were reviewed. Additional HBsAg assay was performed using Architect HBsAg kit (Abbott laboratories, USA) employing chemiluminescent immunoassay method.
  
  
  RESULTS
  Eleven of the 16 patients showed multiple mutations in the "a" determinant. These patients received liver transplantation several years ago and have been treated with hepatitis B immune globulin (HBIG) and antiviral drugs. G145R mutation was found in 8 patients and G145K, D144G, and D144A were also frequently found. Among 9 of the 11 patients tested for HBsAg by Architect HBsAg kit, 8 showed positive results. Among 4 of the remaining 5 patients, only 2 showed weak positive results (< or = 1 IU/mL) in Architect HBsAg kit.
  
  
  CONCLUSIONS
  HBV DNA-positive/HBsAg RIA-negative results were mostly observed in the patients treated with HBIG after liver transplantation, in whom HBIG escape mutations were found. Majority of these cases were positive in Architect HBsAg assay, and it is recommended to use other HBsAg immunoassay methods that are more sensitive than RIA in the detection limit as well as in the detection of escape mutant in hospitals performing liver transplantation.
authors: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Songpa-Gu, Seoul, Korea.
authors: Yong Hak
authors: YH
authors: Sohn
authors: Heung Bum
authors: HB
authors: Oh
authors: Sun Young
authors: SY
authors: Ko
authors: Young Suk
authors: YS
authors: Lim
authors: Oh Joong
authors: OJ
authors: Kwon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000627:therapeutic use; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006509:Hepatitis B / Q000175:diagnosis* / Q000188:drug therapy / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000032:analysis* / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007118:Immunoassay; D007136:Immunoglobulins / Q000627:therapeutic use; D007155:Immunologic Factors / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D011863:Radioimmunoassay
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D007136:Immunoglobulins; D007155:Immunologic Factors; C045213:hepatitis B hyperimmune globulin