Background Intestinal helminths and malaria are among the most prevalent infectious diseases in the tropics. The effect of co-infections on immune response is not clearly understood. We therefore investigated the immune response profile in children with and without symptoms.

Methods A total of 78 afebrile school children (20 helminth/malaria-co-infected, 17 helminth-infected, 19 malaria-infected and 22 uninfected) and 75 febrile children (14 helminth/malaria-co-infected, 16 helminth-infected, 20 malaria-infected and 25 uninfected) were recruited into the study. Helminths were screened using Kato Katz method while malaria parasite screening was done using Giemsa-stained thick blood films. Circulating TNF-α, IFN-γ, IL-1, IL-10 and IL-6 concentrations were assessed by ELISA from serum samples. Data were analysed using analysis of variance.

Results Among the afebrile school children, IL-10 was significantly increased in helminth-infected children compared with helminth/malaria-co-infected, malaria-infected and uninfected groups (p<0.05). IFN-γ was significantly elevated in malaria and malaria/helminth-co-infection relative to helminth alone (p<0.05). IL-1 level was significantly higher in single infection of helminth and malaria relative to co-infection and the uninfected groups (p<0.05). An insignificant difference was observed for IL-6 and TNF-α concentrations across all the four groups while among febrile children. IL-6 was significantly increased among helminth alone and helminth/malaria-co-infection relative to malaria-infected group (p<0.05). IL-10 was significantly elevated in co-infected group compared with helminth- or malaria-infected group while TNF-α was significantly increased in helminth and helminth-malaria co-infection compared with uninfected or malaria-infected group (p<0.05). IFN-γ level was insignificant in the infection groups relative to uninfected group (p<0.05); IL-1 level similar across the groups.

Conclusion Helminth infection seems to upregulate the Th2 immune response among children with symptomatic uncomplicated malaria while there were no significant changes in Th immune response among afebrile children.