Department: Parasitology And Entomology
Human malaria which is caused by Plasmodium spp. is a disease of public health importance. It is known as the world's most prevalent parasitic disease. Following Plasmodium infection, specific antibodies are produced and cytokine activities heightened of which the balance between the pro and anti-inflammatory cytokines helps to regulate immunological status. Profiling such immune markers are therefore necessary for vaccine production, hence the study. The aim of this study was to determine the Immunological Profile of Individuals with Malaria Infection. Ethical approval was obtained from ethics board of Nnamdi Azikiwe University Teaching Hospital (NAUTH) and Anambra State Ministry of Health. Participants were selected from both hospitals and community. Five hundred and forty four (544) individuals were consented; 350 from health facilities while 194 individuals were from Aguleri community. In Anambra State, participants were recruited from NAUTH (43), Iyienu Mission Hospital (135) and Aguleri community. In Lagos participants were recruited from Regina Mundi Catholic Hospital (41) and Agura Health Centre (131). Samples from facility for immunology profile included 58(45.3%) male and 79 (54.7%) female, while community samples included 26 (56.5%) male and 20 (43.5%) female. Axillary temperature was measured using digital thermometer. Venous blood sample was collected. Malaria microscopy was done by two independent readers following WHO standard. Parasite density was computed using patient’s actual White blood cell (AcWBC) count, assumed WBC (AsWBC) of 8000cells/mL and 6000cells/mL. ELISA was used for serology to determine immune profile. AcWBC was determined using haematology analyzer. The malaria prevalence for the study was 35.5% in Lagos facility, 9% in Anambra facility and 9.8% from Aguleri community, Anambra state. Infected individuals had single infection of Plasmodium falciparum with symptomatic parasitaemia ranging from 15-451,440 with a GMPD of 8,009 and asymptomatic 63 – 13,084 with a GMPD of 953. There was no significant discrepancy between parasitaemia obtained with AcWBC and AsWBC of 8,000 cells/mL (p=0.2892) and 6,000 cells/mL(p=0.8858). The parasitaemia discrepancy between the actual parasitaemia (ACP) and assumed parasitamia(ASP) with WBC of 8,000 cells/mL is 1.5%, 4.4%, 13.2%, 5.9%, 9.0% and 66.2% at 0-5%, >5-10%>10-15%, >15-20% >20-25% and>25 respectively; while parasitaemia discrepancy between the ACP and ASP with WBC count of 6,000 cells/mL is 5.9%, 10.3%, 11.8%, 16.2%, 5.9% and 54.4% at 0-5%, >5-10%>10-15%, >15-20% >20-25% and>25 respectively. ASP using a fixed WBC of 8,000 cells/mL and 6,000 cells/mL can be used in place of ACP calculated using AcWBC where AcWBC is not available. Mean IgG plasma level was seen to be higher among the parasitemic asymptomatic group (122.409ng/ml) than parasitemic symptomatic group (85.206ng/ml), there was strong and significant association between IgG with fever and malaria microscopy among the symptomatic group. TNFhad a higher concentration in parasitaemic than aparasitaemic individuals. IL-8 association was seen to be significant in symptomatic age groups 2 and 3 (p=0.001: =0.355; p=0.001: =0.282respectively) of which the highest concentration (600.078mg/L) was seen in the age group 1-5. TNF and IL-8 concentration was seen to be higher in symptomatic than asymptomatic participants. Fever was identified in elevating the plasma level of IgG and TNFwhich could in turn have major roles to play in parasite clearance and immunity as well as disease pathogenesis. Malaria disease severity based on symptoms was found to be independent of parasitemia, sex, and age. With the proposed shift from prevention to elimination phase of malaria control, there is need for more studies on these identified immune markers which may serve as prognostic markers. Further comprehensive test using some of these immune markers may aid malaria vaccine development.