Serum hepatitis B virus (HBV) pregenomic
RNA (
pgRNA) is a
surrogate marker for reflecting the transcriptional activity of covalently closed
circular DNA. However, there is still no standardized assay for the quantitative detection of serum HBV
RNA in
chronic hepatitis B patients. In this study, quantitative polymerase chain reactions for detecting the preC/C-
RNA (preC/C region HBV
pgRNA), SF-RNA (splicing variants-free
pgRNA) and XR-
RNA (X region remained
pgRNA) regions were set up. The dynamic changes of serum
pgRNA splicing variants and 3' terminal truncations were analysed in three retrospective cohorts: 35 treatment-naive chronic HBV-infected patients (cohort A), 52
chronic hepatitis B (CHB) patients who received nucleos(t)ide analogs (
NAs)
therapy for 48 weeks (cohort B) and eight CHB patients who are under long-term
NAs treatment (cohort C). The accuracy and sensitivity of HBV
RNA detection were assessed by the National Standard of HBV
RNA. We confirmed that high proportions of
pgRNA splicing variants and 3' terminal truncations were present and significantly affect the quantitative detection of serum HBV
RNA in both treatment-naive and
NAs-treated CHB patients. To achieve the higher accuracy and sensitivity on the detection of HBV
RNA level, the primers and probes should be designed at the 5' terminal region of HBV genome and outside the mainly spliced sequence of
pgRNA, especially for CHB patients under long-term
NAs treatment. This study would help to better understand the significance of the
pgRNA splicing variants and 3' terminal truncations, and further guide the clinical detection of serum HBV
RNA.