Pro- and anti-inflammatory response profile modulates Plasmodium falciparum malaria outcomes among subjects from Baiyeku, Ikorodu, Lagos, Nigeria.

Abstract

Background Available evidence indicates that the various stages of the malaria parasite life cycle elicit specific immune responses of which the relative levels of pro-inflammatory cytokines are key to disease progression, killing the parasite and mediating disease outcomes. This study will inform immunological interventions against malaria and thus malaria vaccine developments programs/efforts. Methods A total of four hundred and sixty-two participants were screened in a community survey for Plasmodium falciparum (P. falciparum) malaria in Baiyeku, Lagos, Nigeria. P. falciparum parasitaemia was determined by Microscopy using thick and thin blood films stained by Giemsa method using World Health Organization parasitology laboratory protocol whist the serum levels of IL-10, IFNγ and TNFα were determined by Enzyme linked immunosorbent assay [ELISA]. Data analysis was done by One-way Analysis of Variance (ANOVA), Chi square (X²) and Student’s T-test in statistical package for the social sciences (SPSS) version 24 was used to test statistical significance between the symptomatic groups and asymptomatic in relation to age, gender and BMI of the participants.Results A total of 70 (15.2 %) participants were microscopically positive for P. falciparum of which 70% were female, 30% were males while children aged 1-17 years were 65.7%. The geometric mean parasite density (GMPD) was significantly (p=0.001) higher among females than males. The GMPD of participants < 5 years was also significantly (p=0.001) higher than other age groups. About 46.8% of the participants were underweight (BMI < 18.5) also had the highest parasite intensity. The TNFα, IFNγ and IL-10 levels were significantly (p 0.05) higher in the infected than the uninfected participants. IFN-γ values were significantly (p=0.014) elevated among the symptomatic than the asymptomatic participants while there was no significant difference (P>0.053) in the levels of TNF-α and IL-10 (P>0.093) between the symptomatic and asymptomatic participants. Notably, the IL-10 levels were the most elevated amongst the participants with the highest parasite density.Conclusion The prevalence of P. falciparum obtained in this study area which is endemic for malaria is 15.2% suggesting a significant reduction of the disease over time. The awareness of the disease which is now more than before seems to contribute to the lowering of prevalence of the disease in the community. There was a positive relationship between TNF-alpha levels and body temperature. However, compared with the anti-inflammatory cytokine (IL-10) in this study, the levels of the pro-inflammatory cytokines (IFN-γ and TNF-α) were lower due to the negative action of the anti-inflammatory cytokines. IL-10 value increased as parasitemia increased (p=0.073). These findings suggest that higher levels of anti-inflammatory cytokines, especially IL-10 levels may contribute to pathogenesis of uncomplicated malaria.