To investigate whether single nucleotide polymorphisms (SNPs) in Toll-like receptors (TLRs) 3 and 9 affect the susceptibility of hepatitis B virus (HBV) intrauterine transmission, we genotyped 399 neonates for TLR3 (c.1377C/T) [rs3775290] and TLR9 (G2848A) [rs352140] using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). A femoral venous blood sample was obtained from these subjects. Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were measured using chemiluminescence immunoassay kits and hepatitis B virus DNA (HBV DNA) levels were determined by fluorescence quantitative PCR assay. Our results showed that when adjusting for maternal HBeAg, maternal HBV DNA and mode of delivery, allele ‘T’ for SNP c.1377C/T was significantly associated with HBV intrauterine transmission susceptibility [adjusted OR (aOR) 0·55, 95% confidence interval (CI) 0·34–0·91, P = 0·020] and the TT genotype decreased the risk of HBV intrauterine transmission (aOR 0·28, 95% CI 0·09–0·91, P = 0·033). Allele ‘A’ for SNP G2848A was significantly associated with HBV intrauterine transmission susceptibility (aOR 0·62, 95% CI 0·39–1·00, P = 0·048) and the GA genotype protected neonates from HBV intrauterine transmission (aOR 0·45, 95% CI 0·22–0·93, P = 0·031). The TLR3 (c.1377C/T) and TLR9 (G2848A) polymorphisms may be relevant for HBV intrauterine transmission susceptibility, although the reduction in risk to HBV intrauterine transmission is modest and the biological mechanism of the observed association merits further investigation.

To investigate the frequencies of dendritic cells (DCs) and Toll-like receptor 3 (TLR3) in neonates of HBsAg-positive mothers with different HBV serological profiles, we conducted a study in Taiyuan, China. The study included 144 HBsAg-positive mothers and their neonates. The frequencies of DCs and TLR3 were determined using four-colour flow-cytometric analysis. DC and TLR3 frequencies were not related to HBV intrauterine transmission, maternal HBeAg positivity, maternal HBV DNA positivity and HBeAg/HBV DNA double-positivity. The plasmacytoid dendritic cell (pDC) frequencies in neonates whose maternal HBV DNA was >5 × 107 copies/ml decreased significantly compared to that in neonates whose maternal HBV DNA was ⩽5 × 107 copies/ml (Z = − 2·170, P = 0·03) or whose maternal HBV DNA was negative (Z = − 1·981 P = 0·048). This study suggests that neonatal pDC frequencies decrease when maternal HBV DNA loads are >5 × 107 copies/ml.