Post vaccination Unresponsiveness to Recombinant Hepatitis B Vaccine in Healthy children in Basrah: Association with IL-18& INF-gamma Serum Level

Abstract

Background: The association of IL18 with the development of antibodies tohepatitis B virus surface antigen (anti-HBs) in vaccinated children and the role of IL18 and INF-g in promoting the responses to HBV vaccine. We studied whether these cytokines concentrations  contribute to anti-HBs development (titer≥ 10 IU/L) in relation to age and duration from the last vaccine dose administration.

Methods:In 400 vaccinated children who completed the standard series of HBV vaccine quantitatively estimating  the levels of anti-HBsAg, IL18 and INF-g by specific ELISA kits.

The associationsbetween the INF-g and IL18 levels and the risk of impaired anti-HBs development were estimated bycomputing the odds ratios and their 95% confidence intervals .

Results:The rate of  responses among vaccines was 77% leaving  high rate of non-responders (23%) who are susceptible  to infection despite the total vaccination coverage. These non-responders distribution was negatively correlated with age and duration from the last vaccine dose. The pattern of responses to HBsAg vaccine significantly correlated with serum concentration of  IL18 and INF-g,( p = 0.001) .Combination of IL18 levels  with increased quantity of INF-g (p = 0.05), (p = 0.046) was associated with an increased chance for the development of anti-HBs in vaccinated children.

Conclusion: Development of anti-HBs  is associated with quantity  of IL18 and INF-γ  that correlated negatively with age and duration of vaccination  which is associated with overtime loss of protective antibody.