Evaluation of Falciparum Parasitaemia and Associated Inflammatory Cytokines Among Some Malaria-Vulnerable Subjects in Port Harcourt, Rivers State, Nigeria

Abstract

A cross-sectional assessment of some inflammatory cytokines such as tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) concentrations and parasitaemia levels in 162 pregnant women and 160 children infected with Plasmodium falciparum parasites in Port Harcourt, Nigeria, were evaluated. Blood samples collected from the subjects were analyzed, and the blood plasma analysed for cytokine using commercial standard enzyme linked immunosorbent assay kit. Malaria diagnosis and some blood parameters were carried out using standard parasitological and haematological techniques. Pregnant women with falciparum malaria within age group 29-33 years had the highest infection rate of 41%, and mean parasitaemia level of 7955.11±1225.75 parasites/μl while those within the age group 19-23 years had the least mean parasitaemia level of 5042.00±900.18 parasites/μl, and the difference was not statistically significant (P=0.328). Comparatively, children within the age group 3-5 had the highest prevalence of 53.8%, those within 9-11 years had the highest mean parasitaemia level of  4813.03±1180.05 parasites/μl while those within age 6-8 years had lowest mean parasitaemia level of 2324.62±546.63 parasites/μl. The mean difference was statistically significant (P=0.048). The mean concentration levels of cytokines IL-6, and IL-10 (176.32±27.34 pg/ml, and 329.09±19.11 pg/ml, and 376.78±24.95pg/ml respectively) were significantly elevated in pregnant women with severe parasitaemia compared with their concentration levels in mild and moderate parasitaemia; The mean concentration levels of IL-6, and IL-10 (81.79±6.36pg/ml, 24.67±2.00pg/ml, 365.30±40.31 pg/ml, and 318.57±39.29 pg/ml respectively) were significantly higher in children with severe parasitaemia (P=0.6857, 0.1816, P=0.0014, and 0.0347 respectively).The mean cytokine levels of TNF-α, IL-β, IL-6, and IL-10, were significantly elevated in pregnant women and children with P. falciparum infection when compared to their  respective healthy matched controls (P<0.0001). Correlations between plasma levels of IL-6 and P. falciparum parasite density in the study population showed a relatively strong positive linear relationship (P<0.0001). Inflammatory cytokines are involved in immunopathogenesis and immunoregulation of Plasmodium falciparum infection. Cytokines as found in this study could be used as promising prognostic and diagnostic biomarkers for falciparum malaria progression or regression.