Evaluation of Trained Immunity in Individuals Repeatedly Exposed to Plasmonium falciparum Without Clinical Symptoms

Abstract

Background

Malaria is still a big health problem worldwide, and it is the Plasmodium falciparum strain that usually causes the most serious disease. Many people in areas with high transmission of malaria do not show signs of illness, possibly due to the action of the immune system working differently than in other diseases. The phenomenon could be explained by a type of immunity that rewrites the function of immune cells permanently.

Objective:

To determine if moderate exposure to P. falciparum results in trained immunity, without causing clinically noticeable symptoms.

Methods:

This study looked at three groups by conducting a cross-sectional study. The analysis was carried out using samples from asymptomatic parasite carriers, patients with malaria symptoms, and those who were not exposed to malaria (all n=50). Period of study extended from October 2024 to March 2025. IL-6, TNF-α, IL-10, and IFN-γ production in the peripheral blood mononuclear cells was measured by ELISA after cells had been stimulated.

Results:

Individuals without symptoms had much higher levels of IL-6, TNF-α, and IFN-γ (p<0.001) as well as moderate IL-10 responses. It was shown that in trained immunity, there was increased glycolysis and a decline in oxidative phosphorylation.

Conclusion:

Results showed that people who have P. falciparum in their systems without getting sick still have trained innate immunity. As a result, the parasites can be controlled and inflammation was kept to a healthy level. Our results suggest that trained immunity can help with both the development of malaria vaccines and immunotherapeutic approaches in areas where the disease was common.

Keywords:

Trained Immunity, Asymptomatic Malaria, Plasmodium falciparum, Cytokine Response, Innate Immune Memory, Immunometabolism

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