PD-1 mRNA expression is associated with clinical and viral profile and PD1 3'-untranslated region polymorphism in patients with chronic HBV infection.

Programmed cell death-1 (PD-1) is involved in hepatitis B virus (HBV) infection and single-nucleotide polymorphism (SNP) rs10204525 in the 3'-untranslated region (3' UTR) of PD1 gene was shown to be associated with the disease course of HBV infection. This study examined the associations of PD-1 mRNA expression with the clinical and viral profiles and the genotypes of rs10204525 in HBV infection. PD-1 mRNA levels in peripheral blood nuclear cells were determined by real-time quantitative reverse transcription polymerase chain reaction (PCR). PD1 rs10204525 was genotyped by bidirectional PCR amplification of specific alleles. The results showed that patients with chronic HBV infection had significantly elevated PD-1 mRNA levels than healthy controls. Patients with chronic hepatitis and hepatocellular carcinoma had significantly higher PD-1 mRNA levels than healthy controls. HBeAg (+) patients had significantly higher PD-1 mRNA levels than HBeAg (-) patients (P<0.001). PD-1 mRNA levels were sequentially increased with the elevation of HBV DNA levels. In HBV patients, but not in healthy controls, PD-1 mRNA levels were sequentially decreased from rs10204525 genotypes AA, AG to GG and the levels in genotype AA were significantly higher than in genotype GG (P=0.039). These findings suggest that increased PD-1 expression may affect the disease course of chronic HBV infection by facilitating HBV viral replication, and this may at least partially relate to PD1 3' UTR polymorphism.