Parasite density and serum cytokine levels in Plasmodium vivax malaria in Turkey

Abstract

We aimed to investigate the relationship between quantitative Plasmodium vivax parasitaemia and serum cytokine levels in a highly endemic region of Turkey, where such a relation has not been investigated before. Active screening was done in a total of 1316 people residing in 33 villages of Sanliurfa province, Turkey. The study population consisted of 79 consecutive patients with P. vivax malaria, and a control group included 89 healthy subjects. Thick blood smears were examined for malaria parasite and parasite count. Serum samples were analysed for IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10 and IL-12 by the ELISA method. Compared to controls, levels of pro-inflammatory cytokines, i.e. IL-1beta, IL-6 and IL-12, were significantly higher in patients with parasitaemia. There was a significant positive correlation between serum IL-10 and IL-12 levels and the parasite burden (r = 0.264, P = 0.024 and r = 0.264, P = 0.024, respectively). Serum IL-8 levels showed a significant negative correlation with parasite burden (r =-0.356, P = 0.002). There was a positive correlation between IL-8 levels and age, while the opposite was observed for IL-12. High fever was correlated with IL-6 and IL-10 levels. Compared to controls, patients with a parasite count greater than 5000/microL had a significantly higher IL-1beta and IL-10 levels (P < 0.05), while the difference was not significant for patients with a parasite count less than 1000/microL. Thus, we can conclude that pro-inflammatory response against P. vivax gains more importance during periods of increased parasite burden.

On the cytokine/chemokine network during Plasmodium vivax malaria: new insights to understand the disease

“…In the present study, it was shown that P. vivax infection induced increased levels of IL-6 and, after treatment, the plasma levels were restored. These findings were in agreement with previous studies during acute phase [11, 15, 17, 18] although the controversial data in the literature with reduction [10, 14] or increase [11] of IL-6 after the treatment, which might be attributed to convalescence period range (7–45 days) in the different studies [8, 10, 11, 13, 14]. …”

“…Regarding IL-12p40 and TNF, no significant results were observed in the present study. However, differences in literature findings occur for both cytokines in acute phase [7, 8, 10–13, 15, 17–19] and convalescence period [8, 10, 11, 13, 14]. …”

“…While some studies have investigated cytokines/chemokines plasma levels during P. vivax infection [7–15, 17–19], there is still no agreement regarding the production of cytokines/chemokines and protection. It is well established that a pro-inflammatory response is required for parasite elimination, but an immunomodulatory response is also needed to prevent immunopathology [6].…”

“…Concomitantly, it seems to be a consensus that P. vivax infection induces higher levels of IL-10 during acute phase of vivax malaria [7, 8, 10–13, 15, 17–19] and that the cytokine levels were restored to baseline after treatment [8, 10, 11, 14]. Indeed, a previous study demonstrated that CD4 + CD25 + T cells producing IL-10 play a significant role during Plasmodium infection, possibly controlling the pro-inflammatory cytokines IFN-γ and TNF [6].…”

TOLLIP gene variant is associated with Plasmodium vivax malaria in the Brazilian Amazon

“…Several studies have linked high levels of TNF, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10 and IL-12 cytokines with P. vivax infections [4–7]. Severe malaria patients display increase levels of pro-inflammatory cytokines, TNF, IL-6 and IFN-γ [8–11] while acute malaria individuals show high levels of the anti-inflammatory cytokines IL10 [12–14].…”