Decreased Antitoxic Activities among Children with Clinical Episodes of Malaria

Abstract

Healthy Gambian children, children with clinical Plasmodium falciparum malaria, and children with asymptomatic P. falciparum infections were studied to investigate whether antitoxic activities may contribute to protection against malarial symptoms. Markers of inflammatory reactions, soluble tumor necrosis factor receptor I, and C-reactive protein were found in high concentrations in children with symptomatic P. falciparummalaria compared with levels in children with asymptomatic P. falciparum infections or in healthy children, indicating that inflammatory reactions are induced only in children with clinical symptoms. Concentrations of soluble tumor necrosis factor receptor I and C-reactive protein were associated with levels of parasitemia. We detected antitoxic activities in sera as measured by their capacity to block toxin-induced Limulus amoebocyte lysate (LAL) activation. Symptomatic children had decreased capacity to block induction of LAL activation by P. falciparum exoantigen. The decreased blocking activity was restored in the following dry season, when the children had no clinical malaria. Symptomatic children also had the highest immunoglobulin G (IgG) reactivities to conservedP. falciparum erythrocyte membrane protein 1 and “Pfalhesin” (band #3) peptides, indicating that such IgG antibodies are stimulated by acute disease but are lost rapidly after the disease episode. Half of the children with symptomatic infections had low levels of haptoglobin, suggesting that these children had chronicP. falciparum infections which may have caused symptoms previously. Only a few of the children with asymptomatic P. falciparum infections had high parasite counts, and antitoxic immunity in the absence of antiparasite immunity appears to be rare among children in this community.

Impact of asymptomatic malaria parasitaemia on cognitive function and school achievement of schoolchildren in the Yemen Republic

“…This finding has been reported by many studies (e.g. McGuire et al 1996;Hurt et al 1994;Jakobsen et al 1998). CRP was also positively correlated with parasite density (r= 0.46, n= 434, P <0.001) ( fig.…”

Reduction in febrile episodes and dynamics of pyrogenic threshold in Nigerian children with Plasmodium falciparum malaria

“…Our PYT data for the year 2007 aligns with the findings of Bouvier et al [15], Genton et al [26] and Dicko et al [19]. Our finding can be explained by the fact that anti-toxic activity generally decreases with increasing age in children [36]. Since fever is parasite toxin dependent and level of toxin is directly related to parasite biomass in the host [37], there is likelihood of infants requiring higher parasite burden to elicit fever due to malaria than older children.…”

“…In the work of Bouvier et al [15], geometric mean parasite densities of 3448 pf/uL and 918 pf/uL were found in children aged 1-3 y and 4-5 y respectively. The higher parasite density in infants and young children might be due to the poor anti-parasite immunity in this age group [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Generally, antimalarial immunity is acquired gradually and thus improves with age in children [21].…”

“…Generally, antimalarial immunity is acquired gradually and thus improves with age in children [21]. It also depends on repeated exposure to variant parasite infections [36]. The latter is readily achievable in many endemic settings where vector-host interaction is perennial [17].…”

Investigation on nitric oxide and C-reactive protein involvement in anti-leishmanial effects of artemisinin and glucantim on cutaneous leishmaniasis

“…CRP as a protein is mainly regulated at the transcriptional level, induced by cytokines [32]. It is a marker of inflammatory reactions and cytokine activation [33], which is produced early after infection [34]. CRP is reported to be a critical element during a majority of infections [35] and there is a correlation of CRP and NO in some infections including leishmaniasis.…”