In utero sensitization modulates IgG isotype, IFN-γ and IL-10 responses of neonates in bancroftian filariasis.

In utero exposure has been considered as a risk factor for filarial infection. To evaluate the influence of maternal infection on filarial-specific IgG subclass response in neonates and their correlation with plasma levels IL-10 and interferon-γ, 145 pairs of mothers and their respective cord bloods were examined. Transplacental transfer of circulating filarial antigen (CFA) was observed in 34·8% cord bloods from CFA positive mothers. Filarial-specific IgG1, IgG2 and IgG4 responses of cord bloods were found to be positively correlated with CFA of mothers. In contrast, IgG3 responses negatively correlated with CFA of mothers. The % of similarity of recognition pattern in the cord blood with maternal blood was high for IgG3 response than IgG4 in all three groups. An increased levels of IL-10 and decreased levels of interferon gamma (IFN-γ) were observed in cord blood of infected mothers. Interferon gamma was positively correlated with IgG3 and negatively correlated with IgG4 level. On the other hand, IL-10 was positively correlated with IgG4 and CFA, indicating that cytokines may play a role in modulating the immune responses in cord bloods of sensitized foetus. The findings of the study reveal that in utero tolerance or sensitization may influence the filarial-specific immunity to infection in neonates.