Cytokine gene polymorphisms are not associated with anti-PvDBP, anti-PvAMA-1 or anti-PvMSP-119 IgG antibody levels in a malaria-endemic area of the Brazilian Amazon

Study of TNF-α, IFN-γ, TGF-β, IL-6, and IL-10 Gene Polymorphism in Individuals from the Leprosy-Endemic Area in the Brazilian Amazon

This study aimed at verifying the relationship between the polymorphisms of the cytokines tumor necrosis factor-alpha (TNF-α) -308 G → A (rs1800629); interferon gamma (IFN-γ) +874 T → A (rs2430561); transforming growth factor-beta (TGF-β) códon 10 (rs1982073) and códon 25 (rs1800471); interleukin (IL)-6 - 174 G → C (rs180079) and IL-10 - 1082 A→T (rs1800896); -819 C → T (rs1800871); -592 A→C (rs1800872); and leprosy. Blood samples were analyzed from 106 individuals, of whom 24 were paucibacillary (PB), 28 were multibacillary (MB), and 54 were patient contacts. Analysis of cytokine polymorphisms was typified by the polymerase chain reaction technique. For TGF-β +869 T → C and +915 G→C, a tendency to associate the presence of the C allele at codon 10 with leprosy was demonstrated, with the T allele being most frequently found in the CCOSI (P = 0.056). For the polymorphisms IL-10 - 1082 A→T, -819 C→T, and -592 A→C, we found an association of the GCC/GCC genotype with the susceptibility to the disease and the A allele at position 1082 with the leprosy protection. Greater predominance was found of ACC/ATA (31.3%) and GCC/ATA (37.5%) (P = 0.03) and the A allele at position -1082 (76.85%) (P = 0.043) in the CCOSI groups, whereas the GCC/GCC was found in the MB group (22.2%) (P = 0.05). For the other cytokines's single-nucleotide polymorphisms, there were no associations with susceptibility to leprosy. These results are limited by sample size, may not be conclusive, and will need further confirmation in a larger cohort.

The immunology of Plasmodium vivax malaria

Plasmodium vivax infection, the predominant cause of malaria in Asia and Latin America, affects ~14 million individuals annually, with considerable adverse effects on wellbeing and socioeconomic development. A clinical hallmark of Plasmodium infection, the paroxysm, is driven by pyrogenic cytokines produced during the immune response. Here, we review studies on the role of specific immune cell types, cognate innate immune receptors, and inflammatory cytokines on parasite control and disease symptoms. This review also summarizes studies on recurrent infections in individuals living in endemic regions as well as asymptomatic infections, a serious barrier to eliminating this disease. We propose potential mechanisms behind these repeated and subclinical infections, such as poor induction of immunological memory cells and inefficient T effector cells. We address the role of antibody-mediated resistance to P. vivax infection and discuss current progress in vaccine development. Finally, we review immunoregulatory mechanisms, such as inhibitory receptors, T regulatory cells, and the anti-inflammatory cytokine, IL-10, that antagonizes both innate and acquired immune responses, interfering with the development of protective immunity and parasite clearance. These studies provide new insights for the clinical management of symptomatic as well as asymptomatic individuals and the development of an efficacious vaccine for vivax malaria.

Frequency of TNFA, INFG, and IL10 Gene Polymorphisms and Their Association with Malaria Vivax and Genomic Ancestry

Polymorphisms in cytokine genes can alter the production of these proteins and consequently affect the immune response. The trihybrid heterogeneity of the Brazilian population is characterized as a condition for the use of ancestry informative markers. The objective of this study was to evaluate the frequency of -1031T>C, -308G>A and -238G>A TNFA, +874 A>T IFNG and -819C>T, and -592C>A IL10 gene polymorphisms and their association with malaria vivax and genomic ancestry. Samples from 90 vivax malaria-infected individuals and 51 noninfected individuals from northern Brazil were evaluated. Genotyping was carried out by using ASO-PCR or PCR/RFLP. The genomic ancestry of the individuals was classified using 48 insertion/deletion polymorphism biallelic markers. There were no differences in the proportions of African, European, and Native American ancestry between men and women. No significant association was observed for the allele and genotype frequencies of the 6 SNPs between malaria-infected and noninfected individuals. However, there was a trend toward decreasing the frequency of individuals carrying the TNF-308A allele with the increasing proportion of European ancestry. No ethnic-specific SNPs were identified, and there was no allelic or genotype association with susceptibility or resistance to vivax malaria. Understanding the genomic mechanisms by which ancestry influences this association is critical and requires further study.