Correlation of CpG methylation of Pdcd1 gene with PD-1 expression on CD8<sup>+</sup> T cells and medical laboratory indicators in chronic hepatitis B infection.
However, no statistically significant differences were found in the genotype distributions of the PD-1 +7146 G>A and PD-1 +7209 C>T polymorphisms among chronic hepatitis B and spontaneous clearance subjects.