Hepatitis E virus prevalence among blood donors in Dali, China.

BACKGROUND: Hepatitis E virus (HEV) is a nonenveloped RNA virus causing hepatitis E worldwide. The increase in transfusion-transmitted cases of HEV infections from asymptomatic blood donors causing serious illnesses among immunosuppressed recipients has been reported in the past few years. China is one of the most prevalent regions of HEV; as a result, it is important to evaluate the risk of transfusion-transmitted HEV. METHODS: A total of 1864 serum samples (including demographic characteristics) from blood donors were randomly collected from February to March 2018 in Dali city. Anti-HEV IgG, IgM and IgA antibodies and HEV antigen were examined by enzyme-linked immunosorbent assay (ELISA). HEV RNA was detected by real-time PCR. Multivariable logistic regression modelling was used to examine the risk factors associated with HEV prevalence. RESULTS: Overall, the positive rates of anti-HEV IgG, IgM, and IgA antibodies were 13.36% (249/1864), 1.13% (21/1864), and 1.82% (34/1864), respectively. However, none of the 1864 serum samples were HEV antigen positive or HEV RNA positive. Females (16.69%) had a significantly higher HEV seroprevalence than males (13.04%) (odds ratio [OR] 1.34 [95% CI, 1.02-1.75]). Bai (18.85%) donors had a significantly higher HEV seroprevalence than Han (12.21%) blood donors (odds ratio [OR], 1.65 [95% CI, 1.24-2.19] for Bai). CONCLUSIONS: HEV showed a seroprevalence among blood donors in Yunnan Province, some of which were even recent infections, indicating a threat to the safety of blood transfusions. Whether to formulate a strategy for HEV screening in blood centres needs further research.

Evaluate performance of the Abbott chemiluminescent microparticle immunoassay assay for detection of syphilis infection in Chinese blood donors.

BACKGROUND AND OBJECTIVES: To prevent Treponema Pallidum (TP) transmission from blood transfusion, enzyme-linked immunosorbent assay (EIA) for anti-TP has been widely used in routine blood donation screening in China for many years. The aim of this study was to evaluate the performance of the Abbott CMIA assay for detection of anti-TP in Chinese blood donors. MATERIALS AND METHODS: A total of 2420 plasma samples, already routinely screened for anti-TP by two different EIAs, from four blood Centers were tested for anti-TP by Abbott CMIA. Subsequently, all samples with positive results by one or both EIAs and/or by Abbott CMIA were subjected to confirmatory testing (CT) using recombinant immunoblot assay (RIBA) or Treponema Pallidum particle agglutination assay (TPPA). TP infection was defined by a RIBA or TPPA positive. RESULTS: Compared with two EIAs strategy, Abbott CMIA showed a relatively best sensitivity as 98.80% (95% CI: 97.44%-100.16%) and a relatively best specificity as 99.58% (95% CI: 99.30%-99.85%), yielding the best consistency (99.49%) between anti-TP CT results with the highest κ value of .98. CONCLUSION: This is the first study to evaluate the performance of the Abbott CMIA assays for detection of syphilis in Chinese blood donors. Our results suggested that CMIA performed better than both EIAs, and implementation of CMIA replacing two different EIA reagents might help to further reduce the risk of transfusion-transmitted TP infection, decrease unnecessary blood waste and loss of blood donors.

Hepatitis C virus prevalence and incidence estimates among Chinese blood donors.

BACKGROUND: Hepatitis C virus (HCV) is an important transfusion-transmitted virus with global significance. The objective of this study was to evaluate the HCV prevalence and incidence among Chinese blood donors from 2013 to 2016. STUDY DESIGN AND METHODS: Whole blood and apheresis platelet donations collected from five Chinese blood centers from June 1, 2013, to December 31, 2016, were screened in parallel by two different enzyme-linked immunosorbent assays for anti-HIV 1/2, hepatitis B surface antigen, anti-HCV, and syphilis. Screening-reactive samples were further confirmed by western blot. Confirmatory positive rates among first-time and repeat donors were used to estimate the prevalence and incidence rates. Multivariable logistic regression modeling was used to examine factors associated with HCV infection. RESULTS: A total of 1,276,544 donations were collected from five Chinese blood centers, of which an estimated 1203 were confirmed HCV positive. The overall HCV prevalence among first-time donors was 166.56 per 100,000 donors (95% confidence interval, 156.04-177.08). The HCV incidence rate was estimated to be 15.21 (95% confidence interval, 11.83-19.56) per 100,000 person-years among repeat donors. Multivariable logistic regression results showed that increased age, lower educational levels, ethnicity, and occupation were all important factors associated with HCV confirmatory status among first-time donors (p < 0.01). CONCLUSIONS: HCV infection is still an important concern for transfusion safety in China. Our findings indicate that continued strong efforts are needed to monitor and control the risk of transfusion-transmitted HCV infection in China. Moreover, to reduce unnecessary donor loss, HCV donor screening procedures should be improved by incorporating confirmatory testing into routine blood center operations.

[The OmpA-like protein Loa22 from Leptospira interrogans serovar lai induces apoptosis in A549 via Ca2+ signal pathway].

OBJECTIVE: To study the effect of Loa22 mature peptide on the apoptosis of A549 to explore the mechanism of pulmonary impairment in severe forms of leptospirosis. METHODS: Loa22 mature peptide (100 microg/mL) was administered to culture with human lung adenocarcinoma cell line (A549). After 24 hours, the apoptosis, the concentration of calcium of the cells were evaluated. The F-actin cytoskeleton structure was observed and calmdulin (CaM) mRNA expression was also detected. At the same time, after the pretreatment of A549 with PLC specific inhibitor U73122, adding an appropriate amount of mature peptide of Loa22 to act on the cells for a period of time, then detection same index. RESULTS: Loa22 mature peptide could induce the increase of intracellular Ca2+ concentration ([Ca2+]i), CaM expression in mRNA level, the activity of LDH, and cytoskeleton rearrangement of F-actin. But after blocking the signal pathway of PLC, Loa22 mature peptide reduced the increase degree of [Ca2+]i, apoptosis rate, the expression of CaM mRNA, the activity of LDH compared with the unblocked group. CONCLUSION: These data suggest that Loa22 mature peptide involves in the pathological processes of L. interrogans invasion and increase apoptosis in A549 by increase of [Ca2+]i through signaling pathway of PLC.

Effect of Leptospira interrogans outer membrane proteins LipL32 on HUVEC.

Leptospira cause disease through a toxin-mediated process by inducing vascular injury, particularly a small-vessel vasculitis. Breakdown of vessel endothelial cell integrity may increase vessel permeability which is correlated with the changes of tight junction and/or apoptosis in vessel endothelial cells. The specific toxin responsible remains unidentified. In this study, we amplified outer membrane protein LipL32 from the genome of Leptospira interrogans serovar Lai, and it was subcloned in pET32a(+) vector to express thioredoxin(Trx)-LipL32 fusion protein in Escherichia coli BL21(DE3). The protein was expressed and purified, and Trx-LipL32 was administered to culture with human umbilical vein endothelial cells (HUVEC) to elucidate the role of leptospiral outer membrane proteins in vessel endothelial cell. The purified recombinant protein was capable to increase the permeability of HUVECs. And the protein was able to decrease the expression of ZO-1 and induce F-actin in HUVECs display thickening and clustering. Moreover, apoptosis of HUVEC was significantly accelerated. But the fusion partner had no effect in these regards. It is possible that LipL32 is involved in the vessel lesions.

A systematic genotype and subgenotype re-ranking of hepatitis B virus under a novel classification standard.

BACKGROUND AND AIM: It is commonly noticed that chaotic and inefficient subgenotyping are universally used academically and clinically, a standardized HBV genotype/subgenotype classification criterion is urgently acquired. Sequence similarity, which was commonly used for the last three decades, should be upgraded by phylogenetic analysis in genotyping of recombinant-free HBV strains. METHODS: In this study, 4,429 HBV whole-genome sequences were employed to reconstruct the phylogeny of HBV using Bayesian inference. After excluding recombinant sequences, calculating partitioned evolutionary models, excluding recombinant sequences, reconstructing phylogenetic trees, and performing a correlation analysis of genetic distances, geographical distribution and serotypes, we systematically redefined the genotypes and subgenotypes of HBV. RESULTS: Compared to previous taxonomy, fourteen subgenotypes (A5-A7; B5-B9; C2-C4, C7; and D6-D7) were revised in the new standard. Now the HBV is divided into ten genotypes (A-J) and 24 subgenotypes (A1-A3; B1-B5; C1-C6; D1-D6; and F1-F4). CONCLUSION: Our robust genotype/subgenotype new taxonomy has objectively re-molded the current shape of HBV classification. We believe that all future hepatitis B related researches or diagnosis will be benefited under the new HBV genotyping/subgenotyping standards.