Venkatakrishna Shyamala

Prospective Evaluation of Community-Acquired Acute-Phase Hepatitis C Virus Infection

BACKGROUND More than two-thirds of hepatitis C virus (HCV) infections in Western countries are caused by injection drug use, but prospective clinical data regarding the most common mode of HCV acquisition are rare, in part because acute-phase HCV infection is usually asymptomatic. METHODS To characterize acute-phase HCV infection, 179 HCV antibody-negative injection drug users were prospectively evaluated; 62 (34%) of these patients had seroconverted. Twenty of the participants who seroconverted had long-term follow-up with consistent monthly sampling before and after seroconversion, allowing detailed study. RESULTS The first indication of HCV infection was the presence of HCV RNA in serum, which preceded elevation of alanine transaminase levels and total bilirubin levels to > or =2 times baseline in 45% and 77% of patients, respectively. No subjects had jaundice. The median time from initial viremia to seroconversion was 36 days (range, 32-46 days). In one instance, viremia was detected 434 days before seroconversion. However, in no other case was HCV RNA detected >63 days before seroconversion. In subjects with viral persistence, a stable level of HCV RNA in the blood was noted in some subjects within 60 days after the initial detection of viremia, but in others, it was not apparent until >1 year later. In subjects with long-term viral clearance, HCV became persistently undetectable as early as 94 and as late as 620 days after initial viremia. CONCLUSIONS These data underscore the importance of nucleic acid screening of blood donations to prevent HCV transmission and of long-term follow-up to ascertain whether there is viral persistence, at least among injection drug users.

Assessment of the Target-Capture PCR Hepatitis B Virus (HBV) DNA Quantitative Assay and Comparison with Commercial HBV DNA Quantitative Assays

ABSTRACT Recent clinical studies suggest that hepatitis B virus (HBV) load and genotype may be independent predictors of responses to antiviral therapies. However, it is difficult for clinicians to accurately determine viral loads in patient samples because results—both the values and the units of measure—can vary greatly among different tests. Accordingly, the World Health Organization (WHO) has produced the first international standard for HBV DNA for nucleic acid amplification technology (NAT) assays. In the present study, we describe the performance of the target-capture PCR HBV DNA quantitative assay for the quantitation of HBV DNA in clinical samples and reference panels. The range of quantitation was between 50 and 1010 IU/ml. The sensitivity and accuracy of the target-capture PCR assay were demonstrated by using the HBV panel from Quality Control for Medical Diagnostics (QCMD) and the WHO HBV DNA standard. The target-capture PCR assay quantitated the six genotype A members of the QCMD panel and dilutions of the WHO HBV DNA standard within an accuracy of 74 to 142%. Compared to current serological methods, the assay offers window period reductions of 19 days prior to HBV surface antigen and 26 days prior to HBV e antigen detection. The target-capture PCR assay was also compared with four commercially available NAT assays, and the various units of measure were standardized with respect to the international units of the WHO HBV DNA standard. The target-capture PCR assay is a sensitive, accurate, high-throughput, rapid, and reproducible assay for the determination of HBV loads.

Factors in enhancing blood safety by nucleic acid technology testing for human immunodeficiency virus, hepatitis C virus and hepatitis B virus.

In the last few decades through an awareness of transfusion transmitted infections (TTI), a majority of countries have mandated serology based blood screening assays for Human immunodeficiency virus (HIV), Hepatitis C virus (HCV), and Hepatitis B virus (HBV). However, despite improved serology assays, the transfusion transmission of HIV, HCV, and HBV continues, primarily due to release of serology negative units that are infectious because of the window period (WP) and occult HBV infections (OBI). Effective mode of nucleic acid technology (NAT) testing of the viruses can be used to minimize the risk of TTIs. This review compiles the examples of NAT testing failures for all three viruses; analyzes the causes for failure, and the suggestions from retrospective studies to minimize such failures. The results suggest the safest path to be individual donation testing (ID) format for highest sensitivity, and detection of multiple regions for rapidly mutating and recombining viruses. The role of blood screening in the context of the donation and transfusion practices in India, the donor population, and the epidemiology is also discussed. World wide, as the public awareness of TTIs increases, as the recipient rights for safe blood are legally upheld, as the possibility to manage diseases such as hepatitis through expensive and prolonged treatment becomes accessible, and the societal responsibility to shoulder the health costs as in the case for HIV becomes routine, there is much to gain by preventing infections than treating diseases.

Individual donation nucleic acid technology testing to minimize human immunodeficiency virus-1, hepatitis C virus, and hepatitis B virus transfusion transmitted infections

Sir, We read with interest the letter submitted by Mathur et al. in the January-June 2012 issue of the Asian Journal of Transfusion Science.[1] While we agree with our colleagues that the use of nucleic acid technology (NAT) testing, in combination with serology, to detect human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) is the best method for improving blood safety, we disagree with their conclusion that using minipools (MPs) is the best choice for India.