Pro-inflammatory Cytokines Establish a Balance in Symptomatic and Asymptomatic Malaria in Plasmodium falciparum Endemic Regions
Published: 2022-12-26
Page: 96-106
Issue: 2022 - Volume 5 [Issue 1]
Okechukwu Christian Ugwu *
Department of Medical Laboratory Science, School of Basic Medical Sciences, University of Benin, Benin City, Edo State, Nigeria.
Christian Ejike Onah
Department of Medical Laboratory Science, Nnamdi Azikiwe University, Nnewi Campus, Anambra State, Nigeria.
George Onyemaechi Ugwu
Enugu State Primary Healthcare Development Agency, Department of Obstetrics and Gynaecology, College of Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria.
James Ameh
University of Queensland, School of Veterinary Science Queensland Alliance for One Health Science Gatton Campus, Australia.
Helen O. Ogefere
Department of Medical Laboratory Science, School of Basic Medical Sciences, University of Benin, Benin City, Edo State, Nigeria.
Isaiah Nnanna Ibeh
Department of Medical Laboratory Science, School of Basic Medical Sciences, University of Benin, Benin City, Edo State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background and Objectives: Pro-inflammatory cytokines are key in the control of malaria. This study profiled the pro-inflammatory cytokines: tumor necrosis factor-α (TNF-α), Interleukine–2 (IL-2), Interleukine–6 (IL-6) and Interleukine–12 (IL-12) in symptomatic and asymptomatic P. falciparum malaria in Abuja with the aim of elucidating their role in symptomatic and asymptomatic malaria.
Methodology: In the study, 246 plasma samples each from symptomatic and asymptomatic malaria volunteers were assayed for TNF-α, IL-2, IL-6 and IL-12 using Enzyme-Linked Immunosorbent Assay (ELISA) technique and values expressed in pictogram (pg).
Results: The study population comprised 48% male within which 50.4% were symptomatic and 49.6%) asymptomatic, 51.2% was female comprising 49.6% symptomatic and 50.4% asymptomatic. The median plasma concentration of TNF-α in symptomatic and asymptomatic groups of the population were 2.75pg and 2.04pg respectively and differed significantly (P<0.001), likewise IL-6: 4.83pg and 3.01pg (P = 0.014). IL-2 and IL-12 differed significantly in symptomatic and asymptomatic groups but the asymptomatic group showed higher levels of the cytokines: 3.20pg and 3.07pg (P<0.001) for IL-2, and 6.17pg and 3.40pg respectively (P<0.001) for IL-12. When segregated by study areas and age groups, TNF-α, IL-6 and IL-12 showed significant difference between the symptomatic and asymptomatic cases in age group 10-20years; but IL-2 showed no significant difference. TNF-α and IL-6 levels were higher in symptomatic than asymptomatic cases (2.80pg/2.05pg, P<0.001, and 5.2pg/2.42pg, P = 0.023 respectively), IL-12 was higher in asymptomatic case than symptomatic case (3.44pg/5.65pg, P<0.001). In age group 21-39years, TNF-α was significantly higher in symptomatic group than asymptomatic group (2.49pg/2.03pg, P< 0.001) however, IL-2 and IL-12 are significantly higher in asymptomatic than symptomatic cases (3.03pg/3.17pg, P<0.001 and 3.40pg/6.34pg, P < 0.001 respectively). In age group 40 years and above, only IL-2 and IL-12 showed significant difference with asymptomatic cases showing higher plasma levels of the cytokines (3.03pg/3.17pg, P<0.001, and 3.22pg/5.52pg, P<0.001) respectively.
Conclusion: The different patterns exhibited by the pro-inflammatory cytokines (TNF-α and IL-6 that were elevated in symptomatic cases, and IL-2 and IL-12 that were elevated in asymptomatic cases) show interplay among pro-inflammatory cytokines to regulate malaria manifestation in P. falciparum endemic place.
Keywords: Cytokines, symptomatic malaria, asymptomatic malaria, immunity, malaria