th1 and th2 responses are influenced by hla antigens in healthy neonates vaccinated with recombinant hepatitis b vaccine.

the immune response to hepatitis b surface antigen (hbsag) is influenced by several factors, of which hla antigens and balanced secretion of th1/th2 cytokines play important roles. the aim of this study was to evaluate the influence of hla antigens on cytokine secretion by hbsag-stimulated peripheral blood mononuclear cells (pbmc) from healthy neonates vaccinated with recombinant hbsag. pbmcs were isolated from 48 iranian neonates vaccinated with a recombinant hbv vaccine. the cells were stimulated in vitro with rhbsag and the concentration of il-4, il-10, il-12 and ifn-γ were quantitated in culture supernatant by sandwich elisa. hla typing was performed by microlymphocytotoxicity method. significant diminished secretion of both th1 (ifn-γ) and th2 (il-4, il-10) cytokines was observed in hbsag-stimulated pbmc from vaccinees expressing the hla-dr7 compared to dr7 negative vaccinees. similarly, lower production of these cytokines was also observed in vaccinees with dr7-dr53-dq2, b7-dr7-dr53-dq2 and a2-dr7-dr53-dq2 haplotypes (p<0.05, p <0.005). while hbsag-stimulated pbmc of dr13+ subjects produced lower levels of th2-type cytokines (il-4 and il-10), those of hla-b8+ or hla-a9+ subjects produced higher levels of th2-type cytokines. cytokine secretion in response to pha mitogen was not associated with a given hla antigen or haplotype and was similarly represented in all groups of subjects irrespective of their hla complex. these results indicate that hla antigens may differentially influence cytokine secretion by hbsag-specific t-cells of healthy neonates vaccinated with recombinant hb vaccine. this phenomenon may have an important implication for control of the immune response to hbsag vaccine.