Publication Date:
2014-11-22
Description:
HBV-reactivation during immunosuppression can lead to severe acute hepatitis, fulminant liver failure, and death. Here, we investigated HBsAg genetic-features underlying this phenomenon by analyzing 93 patients: 29 developing HBV-reactivation, and 64 consecutive patients with chronic HBV-infection (as control). HBsAg genetic-diversity was analyzed by population-based and ultra-deep sequencing (UDS). Before HBV-reactivation, 51.7% of patients were isolated anti-HBc positive, 31.0% inactive carriers, 6.9% anti-HBc/anti-HBs positive, 6.9% isolated anti-HBs positive, and 3.4% had an overt HBV-infection. 51.7% of HBV-reactivated patients were treated with rituximab, 34.5% with different chemotherapeutics, and 13.8% with corticosteroids only for inflammatory-diseases. 75.9% of HBV-reactivated patients (versus 3.1% of control-patients, P〈0.001) carried HBsAg-mutations localized in immune-active HBsAg regions. Of the 13 HBsAg-mutations found in these patients, 8/13 (M103I-L109I-T118K-P120A-Y134H-S143L-D144E-S171F) reside in major hydrophilic-loop (target of neutralizing-antibodies); some of them are already known to hamper HBsAg-recognition by humoral-response. The remaining 5 (C48G-V96A-L175S-G185E-V190A) are localized in Class-I/II-restricted T-cell epitopes, suggesting a role in HBV-escape from T-cell mediated responses. By UDS, these mutations occurred in HBV-reactivated patients with a median intra-patient prevalence of 73.3%(27.6%-100%) supporting their fixation in viral-population as predominant species. In control-patients carrying such mutations, their median intra-patient prevalence was 4.6%(2.5%-11.3%) (P〈0.001). Finally, additional N-linked glycosylation-sites within major hydrophilic-loop were found in 24.1% of HBV-reactivated patients (versus 0% of chronic-patients, P〈0.001); 5/7 patients carrying these sites remained HBsAg-negative despite HBV-reactivation. N-linked glycosylation can mask immunogenic-epitopes, abrogating HBsAg-recognition by antibodies. In conclusion, HBV-reactivation occurs in a wide variety of clinical-settings requiring immune-suppressive therapy, and correlates with HBsAg-mutations endowed with enhanced-capability to evade immune-response. This highlights the need of a careful patient's monitoring in all immunosuppressive-settings at reactivation-risk, and of establishing a prompt therapy to prevent HBV-related clinical complications. This article is protected by copyright. All rights reserved.
Print ISSN:
0270-9139
Electronic ISSN:
1527-3350
Topics:
Medicine
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