Clinical implications of serum hepatitis B virus RNA quantitation in untreated chronic hepatitis B virus-infected patients

Abstract

Serum hepatitis B virus (HBV) RNA quantitation may be useful for managing untreated chronic HBV-infected patients, but its distribution characteristics and relationship to HBV DNA are unclear. A retrospective cohort including 149 untreated HBV-infected patients was divided into four clinical phenotypes: hepatitis B envelope antigen (HBeAg) positive with normal alanine transaminase (ALT; EPNA) or with elevated ALT (EPEA), HBeAg-negative with normal ALT (ENNA) or with elevated ALT (ENEA). Serum HBV RNA levels were quantified by a high-sensitivity real-time fluorescent quantitative PCR method and liver biopsy was performed in those with undetectable serum HBV DNA or RNA. The detectable serum HBV RNA levels (log₁₀ copies/mL) in EPNA, EPEA, ENNA, and ENEA were 6.02±1.48, 6.54±1.27, 2.51±0.78 and 3.54±1.25, respectively. The low level (< 2.0 log₁₀ copies/mL) comprised mainly of ENNA phenotype (76.9%), while the high level (> 6.0 log₁₀ copies/mL) was HBeAg-positive patients (98.1%). Serum HBV RNA level were significantly correlated with serum HBV DNA and HBsAg in HBeAg-positive phenotypes, but a correlation only with HBV DNA was observed in ENEA patients. Serum HBV DNA and RNA were both independent risk factors associated with elevated ALT in HBeAg-negative patients. Seven serum HBV DNA-undetectable but RNA-detectable patients underwent liver biopsy, showing moderate or severe liver inflammation. Varying serum HBV RNA levels can reflect natural disease phases in untreated HBV-infected patients, indicating that this biomarker could reflect liver inflammation in untreated HBeAg-negative patients as successfully as serum HBV DNA. Serum HBV RNA can complement clinical management strategies when serum HBV DNA is undetectable.

Keywords: HBV RNA; HBeAg negative; antiviral initiation; liver inflammation; untreated.

Figure 1

Distribution characteristics of serum HBV RNA levels across various clinical phenotypes. A. Serum HBV RNA levels in various clinical phenotypes. EPNA vs. EPEA, ENNA, ENEA, P=0.143, 1.475×10^-14 and 2.276×10^-10, respectively; EPEA vs. ENNA, ENEA, P=3.906×10^-29 and 2.712×10^-19, respectively; ENNA vs. ENEA, P=2.261×10^-5. B. The proportion of phenotypes in serial serum HBV RNA levels gradients. ENNA phenotype mainly comprised the low level (< 2.0 log₁₀ copies/mL, n=26) serum HBV RNA gradients (20/26, 76.9%); HBeAg-positive phenotypes (EPNA and EPEA) mainly comprised the high level (> 6.0 log₁₀ copies/mL, n=52) serum HBV RNA gradients (51/52, 98.1%). EPNA, HBeAg-positive with normal ALT; EPEA, HBeAg-positive with elevated ALT; ENNA, HBeAg-negative with normal ALT; ENEA: HBeAg-negative with elevated ALT. LLoD, lower limit of detection.

Figure 2

Pearson correlation analysis between HBV RNA , HBV DNA and HBsAg. A. Correlation between serum HBV DNA and RNA in HBeAg-positive patients; B. Correlation between serum HBV HBsAg and RNA in HBeAg-positive patients; C. Correlation between serum HBV DNA and RNA in HBeAg-negative patients; D. Correlation between serum HBV HBsAg and RNA in HBeAg-negative patients. EPNA, HBeAg-positive with normal ALT; EPEA, HBeAg-positive with elevated ALT; ENNA, HBeAg-negative with normal ALT; ENEA: HBeAg-negative with elevated ALT. HBsAg, hepatitis B surface antigen; LLoD, lower limit of detection.

Figure 3

Significant inflammatory and fibrotic liver pathologic changes in seven DNA-undetectable but RNA-detectable patients (H&E staining, A-C: ×100; D-G: ×200). All seven patients demonstrated moderate or severe liver inflammation with/without fibrosis. (A) G2S1, inflammatory cell infiltration in portal area; patient with serum HBV RNA 1.79 log₁₀ copies/mL, ALT 25.8 U/L; (B) G2S0, hepatocyte spotty necrosis with inflammatory cell infiltration, patient with serum HBV RNA 2.74 log₁₀ copies/mL, ALT 35.0 U/L; (C) G3S2, marked inflammatory cells infiltrate in portal area, patient with serum HBV RNA 1.92 log₁₀ copies/mL, ALT 72.7 U/L; (D) G3S3, marked inflammatory cell infiltrate and fibrous septum formation, patient with serum HBV RNA 1.85 log₁₀ copies/mL, ALT 26.0 U/L; (E) G3S2, hepatocyte piecemeal necrosis with marked inflammatory cell infiltration, patient with serum HBV RNA 2.12 log₁₀ copies/mL, ALT 83.8 U/L; (F) G2S1, inflammatory cell infiltration in portal area, patient with serum HBV RNA 2.42 log₁₀ copies/mL, ALT 47.4 U/L; (G) G2S0, inflammatory cell infiltration in portal area, patient with serum HBV RNA 2.30 log₁₀ copies/mL, ALT 25.2 U/L. G, inflammation grade; S, fibrosis stage.