Quantification of Hepatitis B Virus DNA: Validation of a qPCR Approach to detect Pregnant Women at High Risk to Transmit the Virus in Mali.

INTRODUCTION

Mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is one of the main causes of chronic hepatitis B in endemic regions such as West Africa. Its prevention constitutes an essential element to eliminate HBV. Without intervention, rates of vertical transmission of HBV vary depending on the level of viral replication. The management of this infection is a major concern, particularly the availability of the viral load at an affordable cost in countries with limited resources such as Mali. This study aimed to develop and validate a method for detecting and quantifying HBV DNA using qPCR in pregnant women, a population at risk of transmitting the virus to newborns.

METHODS

We enrolled 74 pregnant women with positive AgHBs in this study. Their viral loads were previously determined at the Reference Centre Lab. We designed specific probes and primers for the HBV PreC gene, for detection and quantification by qPCR. We adapted this new qPCR for quantifying HBV DNA on different real-time PCR machines.

RESULTS

Nine out of nine (9/9), 100% samples with a viral load (VL) between 10000-100000 IU/mL and 4/4,100% with a VL > 100,000 IU/mL were detected and quantified. Of the fifty-five (55) samples with a CV of 12-10000 IU/mL, 38/55, 69% samples with a CV > 1000 IU/mL were detected and 17/55, 30% samples between 12-1000 were not detected. No negative samples (6/6, 100%) were detected by our new qPCR. This in-house real-time PCR showed sensitivity and specificity of 75% and 100% respectively.

CONCLUSION

This work allowed the local development of a sensitive and efficient qPCR protocol for the detection of samples with CVs elevated (>1000 UI/mL). It will detect pregnant women who need to receive antiviral treatment in order to reduce the risk of HBV transmission. This tool could be extended to other high-risk populations such as immunocompromised people.