Hepatitis B surface gene variants isolated from blood donors with overt and occult HBV infection in north eastern Egypt

Abstract

BackgroundMajor hydrophilic region in genomic HBV extending from aa99 to aa169, clustered with a highly conformational epitope, is critical to the antigenicity of hepatitis B surface antigen (HBsAg) and may affect the diagnosis of HBV in HBV screening test. So, this study aimed to characterize variants of S gene product of hepatitis B virus (HBV) isolated from patients with overt or occult HBV infection in north-eastern Egypt.MethodsThe study included sera of two different groups of volunteer blood donors (VBDs), 82 with overt HBV that were positive for HBsAg and anti-HBc and 343 donors negative for HBsAg eligible for donation. Of the latter group, only 44 were positive for anti-HBc. All anti-HBc positive sera were subjected to HBV DNA detection and partial sequence analysis targeting the HBV S gene.ResultsHBV DNA was detected in 22.7 % of HBsAg-/anti-HBc + (10/44 patients) and in 90 % of HBsAg + donors (74/82 patients) with significant statistical difference (P = 0.0001). Phylogenetic analysis showed that HBV strains retrieved from both groups were of genotype D. Amino acid escape mutation T125M was detected in only 2 samples of the occult infection group and in none of the overt group (P = 0.01). Different amino acid substitutions were identified in overt infection group: S143L/T (16.2 %, 12/74) and P120T/S (2.7 %, 2/74). Q129R was significantly more frequent in cases with occult HBV infection (40 %, 4/10) than overt group (6.8 %, 5/74) (P = 0.01).ConclusionsHBV genotype D predominated both in patients with overt and occult HBV infection. Different profiles of amino acid substitutions in the major hydrophilic region were seen in these two groups in Egypt.

Characterization of hepatitis B virus (HBV) preS/S gene mutations in blood donors with occult HBV infection in the Baoji area of North China

“…The clinical features and pathophysiology of HBV infection are determined by the balance between the host-immune response and viral replication competence. 20 HBsAg is the target of neutralizing antibodies and is encoded by the preS/S gene, which includes the preS1, preS2, and S genes. Mutation of the preS/S gene has been suggested as a factor that influences the balance between host and virus and is associated with OBI.…”

Current Knowledge of Occult Hepatitis B Infection and Clinical Implications

“…The prevalence of OBI is difficult to be established, as most of the time it would only be suspected and worked up in some special settings. It may vary substantially in different studies in view of different methodologies (based on serology vs. virology): cryptogenic cirrhosis or advanced liver fibrosis (prevalence, 4 to 38%), [15][16][17] parenteral blood exposure (45%), 18 chronic hepatitis C infection (52%) and human immunodeficiency virus (HIV)-infected patients (0 to 45%), 19 blood donors (0 to 22.7%), 20,21 and hemodialysis patients (0 to 54%). 22…”

“…Blood transfusion is a key transmission route of OBI provided that the screening of blood donors is less intensive. 105 The prevalence of OBI among blood donors varies from country to country, with the highest reported on in Egypt (anti-HBc, 22.7%; HBV DNA, 22.7%) 20 and lowest in Iran (0%). 21 A study of 14,937 young blood donors born between 1992 and 1997 in China, that is, in the era of universal HBV vaccination program, found that 10 of 14,937 (0.067%) donors had detectable serum HBV DNA.…”

Occult Hepatitis Infection in Transfusion Medicine: Screening Policy and Assessment of Current Use of Anti-HBc Testing

“…For these reasons, in some countries such as the USA, Germany, France, Korea, Japan, Thailand, and Australia anti-HBc has been routinely screened together with HBV DNA detection according to each National Blood Bank policy, while in others countries the diagnostic approach may be different (table 1) [13, 29, 62, 71, 75, 77, 79-82, 86, 90, 94]. Moreover, anti-HBc testing was used only for research purposes (table 1) [91][92][93].…”