[Prevalence of Parvovirus B19 Infection in Chinese Xiamen Area Blood Donors].

OBJECTIVE: To estimate the prevalence of parvovirus B19 infection in Chinese Xiamen area blood donors. METHODS: Blood samples from blood donors were tested for detection of parvovirus B19 DNA and antibody. The direct sequencing and genetype analysis of B19 DNA positive samples were performed. RESULTS: Six out of 10452 samples were B19 DNA positive. The viral loads of the 6 samples were between 3.59×102-1.07×104 IU/ml; the positive rate of B19-IgM was 4.64%(50/1078) and B19-IgG was 16.79%(181/1078). The positive rate of B19-IgG increased with ages, and was not related with the sex. CONCLUSION: The overall prevalence of parvovirus B19 infection in blood donors is lower in Chinese Xiamen area than that in other areas, however, there is still a certain percentage of viremia in donors and the attention should be paid to blood safety in the future work.

Molecular characteristics of occult hepatitis B virus from blood donors in southeast China.

The characteristics of 30 carriers with occult hepatitis B virus (HBV) infection (OBI) were compared with those of 30 individuals diagnosed as being HBV carriers at the time of blood donation, 60 asymptomatic carriers, and 60 chronic hepatitis patients. The prevalence of genotype C was significantly higher in carriers with OBIs than in any other HBsAg-positive (HBsAg(+)) group (P < 0.001). Specific amino acid substitutions in the regions from amino acids 117 to 121 and amino acids 144 to 147 located in the major hydrophilic region of the S gene were associated with carriers with OBIs (P < 0.01 for carriers with OBIs versus HBsAg(+) donors, carriers with OBIs versus HBsAg(+) asymptomatic carriers, and carriers with OBIs versus HBsAg(+) chronic hepatitis patients). G145R was the major variation in the HBV isolates responsible for local occult HBV infections.

[Quantitation of HTLV-I proviral load using real-time quantitative PCR with Taqman MGB probe].

A quantitative real-time PCR assay was developed to measure the proviral load of human T-lymphotropic virus type I (HTLV-I) in peripheral blood. The technology utilizes special primers and Taqman MGB fluorescence probe to measure amplification products from the gag-pro-pol polyprotein gene of HTLV-I. HTLV-I copy number was normalized to the amount of cellular DNA by quantitation of the beta-actin gene, The amplification system was sensitive to detect 5 copy/microL. The standard curve had a good linearity when the quantity for the gene was between 10(3) and 10(7) copy/microL (R2 = 0.999). Good reproducibility was observed in each intra- and inter-assay. We also measured proviral load in peripheral blood in 12 HTLV-I seropositive former blood donors. Proviral load for HTLV-I infected donors ranged from 0.015 to 12.819 copy/cell in WBC with the mean of 3.116 copy/cell.

[Surveillance for occult HBV infection and HBsAg variants in blood donors].

Occult hepatitis B virus (HBV) infection status of blood donors in a southern city in China was investigated by immunological assays and nucleic acid testing. Overall, 17 (0.19%, 95% CI: 0.11%-0.30%) of the 9023 HBsAg negative samples were found to be positive for the presence of HBV DNA. "A" epitope sequences were obtained from 14 among them. Mutation(s) in aa124-aa147 existed in 6 (42.9%, 6/14) samples and 4 (66.7%, 4/6)were G145R mutation. Ratio of genotype C in occult donors (10/17) was statistically higher than HBs-positive donors (0/15, P<0.01), which implied that HBV genotype C leaded to occult infection more easily.