ABSTRACT
BACKGROUND: Healthcare workers constitute a population at high risk for HBV infection. Efficient vaccination options are available; however, the individual response to HBV vaccination may vary widely between subjects, potentially due to cytokine profiles and genetic variations. In the present study, we investigated the relationship between IL-17 and IL-22 gene polymorphisms versus non- and low-responsiveness to HBV vaccination in healthcare workers. METHODS: We selected the following IL-17 and IL-22 polymorphisms: rs4711998 (A/G) from IL-17 and rs2227501 (A/T), rs2227503 (A/G), rs1026786 (A/G) from IL-22 sequences genes. These were determined by polymerase chain reaction restriction fragment length polymorphisms. RESULTS: The IL-17 rs4711998 GG genotype had a significantly lower frequency in non-responders compared to low-responders (p=0.025). However, we did not identify a relationship between IL-22 rs1026780, rs2227501 and rs2227503 genotypes and the anti-HBs response following HBV vaccination. CONCLUSION: These data suggest that genetic variation in rs4711998 polymorphisms in the IL-17 cytokine may influence vaccine-induced immune responses to HBV vaccine in healthcare workers.
ABSTRACT
BACKGROUND: Worldwide, healthcare workers (HCWs) show different levels of response to hepatitis B virus (HBV) vaccine. One of the factors associated with vaccine unresponsiveness may be the existence of current or past HBV infection. Regardless of the presence of HBsAg (overt infection), occult HBV infection (OBI, defined as presence of HBV DNA in the absence of HBsAg) might also account for some non- or hypo-response cases. METHODS: Sera from 120 HBsAg-negative HCWs with low and moderate levels of anti-HBs, <10 IU/mL (group I) and <100 IU/mL (group II) respectively, were selected and were examined for OBI by sensitive real-time PCR regardless of HBV serological profiles. Direct sequencing on surface genes was carried out in OBI-positive cases. RESULTS: Four (3.3%) were positive for OBI. All were negative for anti-HBc. Two of the positive cases had moderate levels of anti-HBs (>10 to <100 IU/mL). No significant differences were found between the two groups in terms of risk factors or serological data. No mutations were found in surface proteins of OBI cases. CONCLUSION: OBI in these subjects might be due to other factors rather than presence of "a" determinant mutations. Healthcare workers with inadequate to moderate levels of anti-HBs (<100 IU/mL) following vaccination, regardless of their serological profile for HBV, should be tested for the presence of HBV DNA by sensitive molecular tests. Anti-HBc is not a reliable marker for suspicion of OBI, especially in high-risk group individuals.
