Role of IL-1ß, IL-6 and TNF-α cytokines and TNF-α promoter variability in Plasmodium vivax infection during pregnancy in endemic population of Jharkhand, India.

BACKGROUND: The combinatorial effects of Plasmodium infection, perturbation of inflammatory responses and the dichotomic role of TNF promoter polymorphism has potential clinical and physiological relevance during pregnancy. OBJECTIVE AND METHODS: This coordinated orchestration instigated us to investigate the circulating level of inflammatory cytokines (IL-1ß, TNF-α and IL-6) employing ELISA in a stratified group of samples and the plausible genetic association of TNF-α -308 G/A using PCR-RFLP/sequencing during Plasmodium vivax infection in pregnancy. RESULTS: We observed significantly elevated concentrations of IL-1ß were observed, followed by IL-6 and TNF-α in women with malaria (WWM) and in malaria in pregnancy (MIP). Further, elevated IL-1ß, followed by TNF-α and IL-6 were detected in the non-infected pregnancy group. The differential dynamics of inflammatory cytokine concentration during each trimester of pregnancy with and without P. vivax infection were detected. For the first time, a high level of IL-6 was observed in the first trimester of MIP and high IL-1ß in healthy pregnancies. In the second trimester, however, we observed a high level of IL-1ß in the MIP group compared to a sustained high level of IL-1ß in the healthy pregnancy group. In the third trimester, high IL-1ß was sustained in the MIP group and healthy pregnancies acquired a high TNF-α level. The genotypic distribution for the TNF-α promoter -308 G/A position was observed to be nonsignificant and mildly associated during MIP (OR = 1.4) and in WWM (OR = 1.2). Moreover, based on genotypic distribution, we observed a well-correlated and significantly elevated TNF-α concentration in the mutant homozygote genotype (AA; p = 0.001) followed by heterozygotes (GA; p = 0.0001) and ancestral genotypes (GG; p = 0.0001) in both MIP and WWM subjects. CONCLUSION: The observation of elevated IL-1ß and IL-6 in MIP and TNF-α in WWM may be regarded as a prognostic inflammatory marker of infection and pregnancy. Most particularly, the TNF-α concentration and its polymorphic variability in the promoter region may indicate genetic susceptibility and mildly influence the risk for P. vivax infection during pregnancy and in women with malaria.

Polymorphism in glutathione S-transferase P1 is associated with susceptibility to Plasmodium vivax malaria compared to P. falciparum and upregulates the GST level during malarial infection.

Glutathione S-transferase P1 (GSTP1) is a member of the GST superfamily, which has well-established multiple roles in various infectious and parasitic diseases. The genetic regulation of GSTP1 has been extensively studied. Thus, its biological significance and disease association prompted us to investigate the role of GSTP1 polymorphisms in Plasmodium-mediated pathogenesis in infected humans. The genotypic distribution of Ile105Val in Plasmodium vivax infection was observed to be significant and strongly associated (OR=4.5) with the progression of pathology, whereas in P. falciparum infection no significant association was observed compared to healthy subjects. Interestingly, we observed significant elevation of GST in vivax infection, with both genotypes Ile105Val and Val105Val, compared to healthy subjects, whereas in P. falciparum infection we found marginally elevated GST levels of mutated genotypes but significantly depleted compared to healthy subjects. Further, during vivax and falciparum infection overall significant elevations of glutathione, glutathione peroxidase, and GST levels were observed. Expression of both GSTP1 mRNA and protein was significantly upregulated during vivax infection compared to falciparum infection and both were significantly upregulated compared to the levels in healthy subjects as well. These studies suggest that GSTP1 polymorphism is involved in the pathogenesis of malaria and it may serve as a valuable molecular marker, possessing a promising rationale for diagnostic potential in assessing disease progression during clinical malaria.

Alleles -308A and -1031C in the TNF-alpha gene promoter do not increase the risk but associated with circulating levels of TNF-alpha and clinical features of vivax malaria in Indian patients.

The biological significance of TNF promoter polymorphism and infectious disease association prompted us to investigate whether TNF-alpha -308 G/A and -1031 T/C promoter polymorphisms are associated with Plasmodium vivax infection, cellular TNF-alpha level and possibly with clinical symptoms by employing PCR-RFLP methods. An overall significant elevation of serum TNF-alpha, IL-6 content (p=0.0002, p=0.002, respectively), whereas highly significant depletion of IL-10 content (p=0.0001) was observed in vivax patients. In addition, TNF-alpha concentration in patients with and without fever were found to be significant (p=0.0001, p=0.0004, respectively). The genotypic distribution for -308 G/A and -1031 T/C positions were found non significant, but it was clinically potent to observe statistically significant distribution of genotypes (p=0.032) in patients with and without fever. Furthermore, the TNF-alpha level in TNF1 and TNF2 genotype for -308 position was significantly higher (p=0.010, p=0.006 respectively). In case of -1031 position TNF-alpha level was significant in ancestral (TT) genotype (p=0.0007) in patients compared to healthy subjects and significantly higher in rare (CC) genotype (p=0.021) as compared to ancestral genotype. In addition, the two polymorphisms 308G/A and -1031T/C were in highly significant LD (D'=0.7992, r(2)=0.6005, p=0.0001) in the patients as well as it is interesting to report that the distribution of novel 308A: 1031C alleles associated haplotypes are nearly the same in patients (0.2610) and in healthy subjects (0.2636). In view of present observation of promoter polymorphism with TNF-alpha level and other clinical parameters of vivax infection, we suggest that evaluation of TNF level and its polymorphisms in the promoter region may be considered to be reliable molecular and immunological markers, possess promising rational for diagnostic potential and immunotherapeutic interventions in clinical vivax malaria. Genetic variation in the promoter region is of biological significance and may play important roles in host defense mechanisms against vivax infection by enhancing cell-mediated immunity and stimulating the protective immunological cascade.

Decreased glutathione-S-transferase activity: diagnostic and protective role in vivax malaria.

OBJECTIVES: The study was undertaken to establish data on the comparative status of antioxidant enzyme GST activity, levels of lipid peroxidation and catalase activity during pathology of Plasmodium vivax malaria in Indian population. We investigated whether serum and plasma glutathione-S-transferase activity in vivax patients are unique to the disease or act as one of the important antioxidant marker for diagnostic potential and candidate for chemoprevention. METHODS: We measured activity of antioxidant enzyme GST, levels of lipid peroxidation and catalase activity during vivax infection. RESULTS: Mean activity of antioxidant enzyme GST in patients serum and plasma were less (6.43 and 5.65 IU/L respectively) than healthy subjects (11.65 and 10.09 IU/L respectively). Lipid peroxidation level and catalase activity of patients (1.77 micromol/L and 29.64 U/mL) with vivax malaria were higher than those of healthy subjects (1.03 micromol/L and 10.87 U/mL). GST activity in serum and plasma was inversely correlated with age in case of vivax patient and were found significant (R2=0.1907 and 0.1605 and p<0.0007 and p<0.01). CONCLUSIONS: In view of the present findings we suggest that GST, lipid peroxidation and catalase evaluation may be considered to be reliable biochemical markers and possess promising rational for diagnostic and therapeutic potential in vivax malaria. Decreasing GST activity and elevated activity of lipid peroxidation and catalase may play important roles in host defence mechanisms against vivax infection by up-regulating oxidative defence mechanisms.