Characteristics of amino acid substitutions within the “a” determinant region of hepatitis B virus in chronically infected patients with coexisting HBsAg and anti-HBs - 22/11/20
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Highlights |
• | There were more amino acid substitutions in HBsAg+/anti-HBs+ patients compared to the control subjects, especially within the first loop of the “a” determinant region in HBsAg+/anti-HBs+ patients. |
• | The most frequent amino acid substitution was located at position s126 and the predominant substitution was sI126T. |
• | sC137R was showed for the first time in HBsAg+/anti-HBs+ patients with genotype C. |
• | The preferred amino acid substitutions with genotypic heterogeneity was revealed. |
Summary |
Objectives |
Simultaneous positivity for both hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) is an atypical serological profile in chronic hepatitis B (CHB) patients. The exact mechanisms underlying the uncommon profile remains unclear. The aim of this study was to analyze the characteristics of amino acid substitutions within the “a” determinant region in a large cohort of CHB patients with coexistence of HBsAg and anti-HBs.
Methods |
In total 8687 CHB patients, of which 505 had coexisting HBsAg and anti-HBs, were enrolled in this study. Mutations within the “a” determinant region in 131 HBsAg+/anti-HBs+ patients and 150 age and gender matched HBsAg+/anti-HBs− patients were determined by direct sequencing and the characteristics of amino acid substitutions were analyzed.
Results |
The prevalence of coexistence of HBsAg and anti-HBs in the CHB patients was 5.81%. Compared to the control subjects, there were more amino acid substitutions in HBsAg+/anti-HBs+ patients (30.5% vs. 12.7%, P<0.001), especially within the first loop of the “a” determinant region. The most frequent amino acid substitution was located at position s126 and the predominant substitution was sI126T in HBsAg+/anti-HBs+ patients with genotype C. The frequency of additional N-glycosylation sites in HBsAg+/anti-HBs+ patients and the control subjects was 3.8% and 0.6%, respectively.
Conclusions |
The accumulation and diversity of amino acid variations within “a” determinant region might contribute to the coexistence of HBsAg and anti-HBs. These findings extend understanding of the genetic mechanism of this atypical serological profile in CHB patients.
Le texte complet de cet article est disponible en PDF.Keywords : Chronic hepatitis B, HBsAg, Anti-HBs, “a” determinant region, Amino acid substitution
Plan
Vol 44 - N° 6
P. 923-931 - novembre 2020 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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