OBJECTIVE: To investigate the molecular basis of occult hepatitis B virus (HBV) infection (OBI) in Asian blood donors. DESIGN: OBI donors from Hong Kong, Malaysia, Singapore, Taiwan and Thailand were tested for HBV serological markers, and strains were molecularly characterised. RESULTS: Among 138 confirmed OBI carriers (median age 47 years), HBV genotypes B and C were dominant (60% and 34%, respectively) in agreement with the genotype distribution in chronically infected donors in the region. Viral load ranged between unquantifiable and 3670 IU/ml (median 11 IU/ml). Eleven per cent of OBIs showed an unusual anti-HBs-only serological profile without evidence of past vaccination for most of these individuals. Occult HBV strains showed a higher genetic diversity than strains from matched hepatitis B surface antigen (HBsAg)+ donors, irrespective of genotype. No unique genetic signature or evidence of reduced replication competence was found. Mutations in the vicinity of the pre-S2/S splice donor site were common in OBI(B) (44%) and OBI(C) (36%) strains. S regions from four OBI cases were transfected in HuH7 cells. Results showed limited HBsAg secretion and suggested that mutations disrupting the splice donor site structure may affect pre-S2/S mRNA splicing. CONCLUSIONS: There is indirect evidence that incomplete immune control is involved in the occurrence of OBI in Asian blood donors infected with genotypes B and C as observed in Europe with genotype A2 but to a lower extent than with genotype D. A post-transcriptional mechanism may play a role in HBsAg expression in some OBIs irrespective of HBV genotype.
OBJECTIVE: To investigate the molecular basis of occult hepatitis B virus (HBV) infection (OBI) in Asian blood donors. DESIGN: OBI donors from Hong Kong, Malaysia, Singapore, Taiwan and Thailand were tested for HBV serological markers, and strains were molecularly characterised. RESULTS: Among 138 confirmed OBI carriers (median age 47 years), HBV genotypes B and C were dominant (60% and 34%, respectively) in agreement with the genotype distribution in chronically infected donors in the region. Viral load ranged between unquantifiable and 3670 IU/ml (median 11 IU/ml). Eleven per cent of OBIs showed an unusual anti-HBs-only serological profile without evidence of past vaccination for most of these individuals. Occult HBV strains showed a higher genetic diversity than strains from matched hepatitis B surface antigen (HBsAg)+ donors, irrespective of genotype. No unique genetic signature or evidence of reduced replication competence was found. Mutations in the vicinity of the pre-S2/S splice donor site were common in OBI(B) (44%) and OBI(C) (36%) strains. S regions from four OBI cases were transfected in HuH7 cells. Results showed limited HBsAg secretion and suggested that mutations disrupting the splice donor site structure may affect pre-S2/S mRNA splicing. CONCLUSIONS: There is indirect evidence that incomplete immune control is involved in the occurrence of OBI in Asian blood donors infected with genotypes B and C as observed in Europe with genotype A2 but to a lower extent than with genotype D. A post-transcriptional mechanism may play a role in HBsAg expression in some OBIs irrespective of HBV genotype.
Authors: Sumathi Ramachandran; Jamel A Groves; Guo-Liang Xia; Paula Saá; Edward P Notari; Jan Drobeniuc; Amanda Poe; Natasha Khudyakov; Sarah F Schillie; Trudy V Murphy; Saleem Kamili; Chong-Gee Teo; Roger Y Dodd; Yury E Khudyakov; Susan L Stramer Journal: Transfusion Date: 2018-11-30 Impact factor: 3.157
Authors: S K Sarin; M Kumar; G K Lau; Z Abbas; H L Y Chan; C J Chen; D S Chen; H L Chen; P J Chen; R N Chien; A K Dokmeci; Ed Gane; J L Hou; W Jafri; J Jia; J H Kim; C L Lai; H C Lee; S G Lim; C J Liu; S Locarnini; M Al Mahtab; R Mohamed; M Omata; J Park; T Piratvisuth; B C Sharma; J Sollano; F S Wang; L Wei; M F Yuen; S S Zheng; J H Kao Journal: Hepatol Int Date: 2015-11-13 Impact factor: 6.047
Authors: Zeinab N Said; Manal H El Sayed; Iman I Salama; Enas K Aboel-Magd; Magda H Mahmoud; Maged El Setouhy; Faten Mouftah; Manal B Azzab; Heidi Goubran; Amal Bassili; Gamal E Esmat Journal: World J Hepatol Date: 2013-02-27