The biological significance of
TNF promoter polymorphism and infectious disease association prompted us to investigate whether TNF-α
x2212;308 G/A and
x2212;1031 T/C promoter polymorphisms are associated with
Plasmodium vivax infection, cellular TNF-α level and possibly with clinical symptoms by employing PCR-RFLP methods. An overall significant elevation of serum TNF-α, 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-α concentration in patients with and without fever were found to be significant (
p = 0.0001,
p = 0.0004, respectively). The genotypic distribution for
x2212;308 G/A and
x2212;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-α level in TNF1 and TNF2 genotype for
x2212;308 position was significantly higher (
p = 0.010,
p = 0.006 respectively). Incase of
x2212;1031 position TNF-α 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
x2212;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-α 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.