Status: Funded - Closed
Cytokine expression profiles in Kenyan children with helminth infection
Joshua Lacsina, M.D., Ph.D.
An estimated one billion school-age children worldwide are at high risk for helminth infection. Children are particularly susceptible to high-burden infections, which can result in both immunosuppression and pathologic inflammation. The disruption of cytokine signaling by helminths has been proposed to impair the ability to mount protective immune responses to vaccination. To investigate the relationship between pediatric helminth infection, Th1 vs. Th2 cytokine balance, and antibody responses to measles vaccination, we performed a cross-sectional study nested within a larger surveillance study of pediatric diarrhea and febrile illness at three clinical sites in Western Kenya. Plasma and stool samples were collected at the time of enrollment from eligible children aged 1 through 5 years with documented measles vaccination. Shortly after collection, stool samples were tested by Kato-Katz and formol-ether concentration methods to diagnose helminth infection. Plasma from children with and without helminth infection was analyzed by ELISA to compare levels of the Th1 cytokine IFN-γ, the Th2 cytokines IL-5 and IL-10, and anti-measles IgG. Out of 363 children screened from the parent study, 92 were enrolled, of whom 12 were helminth infected, for a prevalence of 13%. No statistically significant differences were observed between helminth negative and positive children in plasma levels of IFN-γ, IL-5, IL-10, or anti-measles IgG titers. These findings may reflect the ability of helminths to evade immune detection activation, but interpreting the results is limited by underpowering from the low enrollment in the helminth positive arm. Current research is focused on identifying epidemiologic and socioeconomic factors that influence susceptibility to helminth infection and antibody responses to measles vaccination among children in Western Kenya. It is anticipated that the results of these studies will help identify public health interventions that are most likely to decrease helminth prevalence and improve responsiveness to measles vaccination. Furthermore, we hope to define cytokine signatures that can be used to evaluate the efficacy of novel vaccine adjuvant formulations.