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

Summary 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.