Comprehensive analysis of hepatitis B virus infections in blood donors in southern China that are surface antigen positive but nucleic acid testing negative

Cost-benefit analysis of serological and nucleic acid testing for hepatitis B virus in blood donors in southern China

BACKGROUND

Most Chinese blood centers have implemented mini pool (MP) HBV nucleic acid testing (NAT) together with HBsAg ELISA in routine blood donor screening for HBV infection since 2015, and a few centers upgraded MP to individual donation (ID) NAT screening recently, raising urgent need for cost-benefit analysis of different screening strategies. In an effort to prevent transfusion-transmitted infections (TTIs) for HBV, cost-benefit analyses of three different screening strategies: HBsAg alone, HBsAg plus MP NAT and HBsAg plus ID NAT were performed in blood donors from southern China where HBV infection was endemic.

METHODS

MP-6 HBV NAT and ID NAT were adopted in parallel to screen blood donors for further comparative analysis. On the basis of screening data and the documented parameters, the number of window period (WP) infection, HBV acute infection, chronic hepatitis B infection (CHB) and occult hepatitis B infection (OBI) was evaluated, and the potential prevented HBV TTIs and benefits of these three strategies were predicted based on cost-benefit analysis by an estimation model.

RESULTS

Of 132,323 donations, the yield rate for HBsAg-/DNA + screened by ID NAT (0.12%) was significantly higher than that by MP NAT (0.058%, P < 0.05). Furthermore, the predicted transfusion-transmitted HBV cases prevented was 1.25 times more by ID NAT compared to MP-6 NAT. The cost-benefit ratio of the universal HBsAg screening, HBsAg plus ID NAT and HBsAg plus MP NAT were 1:58, 1:27 and 1:22, respectively.

CONCLUSIONS

Universal HBsAg ELISA screening in combination with HBV ID NAT or MP-6 NAT strategies was highly cost effective in China. To further improve blood safety, HBsAg plus HBV DNA ID NAT screening should be considered in HBV endemic regions/countries.

Serological and Molecular Characterization of Occult HBV Infection in Blood Donors from South Italy

Despite good vaccine coverage and careful blood donor selection policies, hepatitis B virus (HBV) is still the most frequent viral infection among blood donors (BDs) in Italy, mostly in the occult form (OBI). We studied the virological features of OBI in BDs from South Italy by serology, molecular testing for HBV-DNA, and sequencing for HBV genotypes and mutations. One hundred and two samples from 95 BDs (22.1% first time, 87.9% regular, median age 57 years) positive for HBV-DNA and negative for HBsAg were retrospectively analyzed. HBV biomarkers were detected in 96.9% (anti-HBc in 44.2%, anti-HBc plus anti-HBs in 49.5%, anti-HBs alone in 3.2%). No risk factor was declared by 45.3% of donors. HBV-DNA levels were very low (median: 7 IU/mL). All samples harbored HBV genotype D and single or multiple mutations in the S gene were found in 28/36 sequences analyzed and in 75% of donors. Mutations were unrelated to gender, donor group or serological patterns. An HBsAg assay with enhanced sensitivity was positive in samples from seven donors (7.4%), two of which negative for HBV-DNA by real-time PCR. OBI still represents a risk for HBV transmission from blood donations; screening by highly sensitive serological and molecular assays is warranted.

Comparative analysis of hepatitis B virus infections in blood donors born before and after the implementation of universal HBV vaccination in southern China

BACKGROUND

In China, the vaccinated blood donors have rapidly increased by recent years, which may impact blood safety. The true prevalence of HBV between vaccinated blood donors and non-vaccinated blood donors should be explored.

STUDY DESIGN AND METHODS

The samples of blood donors were collected and detected for serologic markers of HBV in the Shenzhen Blood Centre (SZBC). The discrepant results were tested with commercial electrochemiluminescence immunoassay (ELCI) for HBsAg, anti-HBs, HBeAg, Anti-HBe and Anti-HBc, alternative MPX ID NAT, nested PCR, and a quantitative real-time polymerase chain reaction (qPCR) assay for HBV DNA. The serological and molecular characteristics of HBV infected blood donors were analysed, and the effects on blood safety for donors born before and after the implementation of universal HBV vaccination were compared.

RESULTS

Out of 242 presumed HBV infected donors from 26 318 donations, 131 (0.49%, [95% CI, 0.43-0.59]) chronic HBV infections (CHB, HBsAg detected with or without DNA), 58 (0.22%, [95% CI, 0.17-0.28]) occult hepatitis B infections (OBI, HBsAg not detected, assume anti-HBc positive and/or anti-HBs with HBV DNA) and 3 (0.011%, [95% CI, 0.0023-0.033]) window period (WP) infections were confirmed respectively. There were 28 CHBs (0.44%), 7 OBIs (0.11%) and 1 WP (0.016%) from vaccinated blood donor and 103 CHBs (0.52%), 51 OBIs (0.26%) and 2 WPs (0.01%) from non-vaccinated blood donor. The HBV+ (CHBs, OBIs and WPs) rate (0.56%) in vaccinated donors was lower than in non-vaccinated donors (0.78%, p < 0.05). The HBsAg titers of vaccinated infected blood donors (Median: 128.8 IU/ml) were much higher than non-vaccinated infected blood donors (58.4 IU/ml). The OBI yield rates in the vaccinated blood donors was significantly lower than the non-vaccinated blood donors (p < 0.05). There 102/124 (82.3%) samples were genotype B, 22/124 (17.7%) were genotype C respectively. There was no significant difference in the distribution of genotype between non-vaccinated blood donors (B/C, 86/17) and vaccinated blood donors (B/C, 23/6; p > 0.05). High frequency of vaccine escape mutations M133L (32.4%) and E164G in S region of genotype B strains and substitution L175S (40.9%) related to vaccine escape in S region of genotype C strains were identified.

CONCLUSION

The universal HBV vaccination program markedly reduces the risk of HBV infection in blood donors, and provides a significant guarantee for the safety of blood transfusion. Several important mutations detected related vaccine escape and notable mutations needed further investigated.

Human Parvovirus B19 May Be a Risk Factor in Myasthenia Gravis with Thymoma

PURPOSE

Our previous studies have demonstrated that human parvovirus B19 (B19V) is involved in the pathogenesis of thymic hyperplasia-associated myasthenia gravis (MG). However, more cases need to be assessed to further elucidate the relationship between this virus and thymoma-associated MG.

MATERIALS AND METHODS

The clinicopathological characteristics, presence of B19V DNA, and B19V VP2 capsid protein expression of 708 cases of thymomas were investigated using nested polymerase chain reaction (PCR), TaqMan quantitative (q) PCR, immunohistochemistry, fluorescent multiplex immunohistochemistry, and electron microscopy.

RESULTS

Patients with MG or ectopic germinal centers (GCs) were significantly younger than those without MG (P < 0.0001) or GCs (P = 0.0001). Moreover, significantly more GCs were detected in thymomas associated with MG than in those without MG (P < 0.0001). The results of nested PCR and TaqMan qPCR were consistent, and B19V DNA positivity was only associated with presence of GCs (P = 0.011). Immunohistochemically, positive staining was primarily detected in neoplastic thymic epithelial cells (TECs) and ectopic GCs. The positive rate of B19V VP2 was significantly higher in thymoma with MG or GCs than in thymoma without MG (P = 0.004) or GCs (P = 0.006). Electron microscopy showed B19V particles in the nuclei of neoplastic TECs and B cells from GCs.

CONCLUSIONS

We conclude that the pathogenesis of MG is closely associated with the presence of GCs, and B19V infection is plausibly an essential contributor to formation of ectopic GCs in thymoma. To the best of the authors' knowledge, this is the first study to elucidate the role of B19V in thymoma-associated MG and provide new ideas for exploring the etiopathogenic mechanism of MG.

Molecular characteristics of HBV infection among blood donors tested HBsAg reactive in a single ELISA test in southern China

Background

Hepatitis B virus (HBV) infection is a major concern for blood safety in high-prevalence HBV countries such as China. In Shenzhen, dual hepatitis B surface antigen (HBsAg) enzyme-linked immunosorbent assays (ELISAs) have been adopted in parallel with nucleic acid testing (NAT) for donors for over a decade. A small proportion of blood donors test reactive (R) for HBsAg but negative through routine NAT, which can lead to HBV infection with an extremely low viral load.

Objectives

We aimed to investigate and analyze the molecular characteristics of HBV among blood donors that tested HBsAg R in a single ELISA test.

Methods

Blood donations were evaluated in this study if confirmed HBsAg R through one of two ELISA kits. Samples with non-reactive (NR) results by NAT were collected and tested for HBsAg by chemiluminescent microparticle immunoassay (CLIA) with a neutralization test. The level of HBsAg was further assessed by electrochemiluminescence immunoassay (ECLIA). The viral basic core promoter (BCP) and pre-core (PC) and S regions were amplified by nested PCR. Quantitative real-time PCR (qPCR) for viral load determination and individual donation (ID)-NAT were adopted simultaneously. HBsAg was confirmed with CLIA, ECLIA, nested PCR, qPCR, and ID-NAT.

Results

Of the 100,252 donations, 38 and 41 were identified as HBsAg R with Wantai and DiaSorin ELISA kits, respectively. Seventy-nine (0.077%, 79/100,252) blood samples with ELISA R-NR and NAT NR results were enrolled in the study. Of these, 17 (21.5%,17/79) were confirmed as HBsAg-positive. Of the 14 genotyped cases, 78.6% (11/14) were genotype B, and C and D were observed in two and one sample, respectively. Mutations were found in the S gene, including Y100C, Y103I, G145R, and L175S, which can affect the detection of HBsAg. A high-frequency mutation, T1719G (93.3%), was detected in the BCP/PC region, which reduced the viral replication.

Conclusion

A small number of blood samples with HBsAg ELISA R-NR and NAT NR results were confirmed as HBV infection, viral nucleic acids were found in most of the samples through routine NAT methods. It is necessary to employ more sensitive and specific assays for the detection of HBV infection among blood donors.