Association between IL1 gene polymorphism and human African trypanosomiasis in populations of sleeping sickness foci of southern Cameroon

PLoS Negl Trop Dis. 2019 Mar 25;13(3):e0007283. doi: 10.1371/journal.pntd.0007283. eCollection 2019 Mar.

Abstract

Background: Human African Trypanosomiasis (HAT) is a neglected tropical disease caused by infections due to Trypanosoma brucei subspecies. In addition to the well-established environmental and behavioural risks of becoming infected, there is evidence for a genetic component to the response to trypanosome infection. We undertook a candidate gene case-control study to investigate genetic associations further.

Methodology: We genotyped one polymorphism in each of seven genes (IL1A, IL1RN, IL4RN, IL6, HP, HPR, and HLA-G) in 73 cases and 250 controls collected from 19 ethno-linguistic subgroups stratified into three major ethno-linguistic groups, 2 pooled ethno-linguistic groups and 11 ethno-linguistic subgroups from three Cameroonian HAT foci. The seven polymorphic loci tested consisted of three SNPs, three variable numbers of tandem repeat (VNTR) and one INDEL.

Results: We found that the genotype (TT) and minor allele (T) of IL1A gene as well as the genotype 1A3A of IL1RN were associated with an increased risk of getting Trypanosoma brucei gambiense and develop HAT when all data were analysed together and also when stratified by the three major ethno-linguistic groups, 2 pooled ethno-linguistic subgroups and 11 ethno-linguistic subgroups.

Conclusion: This study revealed that one SNP rs1800794 of IL1A and one VNTR rs2234663 of IL1RN were associated with the increased risk to be infected by Trypanosoma brucei gambiense and develop sleeping sickness in southern Cameroon. The minor allele T and the genotype TT of SNP rs1800794 in IL1A as well as the genotype 1A3A of IL1RN rs2234663 VNTR seem to increase the risk of getting Trypanosoma brucei gambiense infections and develop sleeping sickness in southern Cameroon.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Alleles
  • Cameroon / epidemiology
  • Case-Control Studies
  • Child
  • Female
  • Genetic Association Studies
  • Genetic Predisposition to Disease
  • Genotype
  • Humans
  • Male
  • Middle Aged
  • Neglected Diseases / epidemiology
  • Neglected Diseases / genetics*
  • Neglected Diseases / parasitology
  • Polymorphism, Single Nucleotide / genetics*
  • Risk
  • Trypanosoma brucei gambiense / physiology*
  • Trypanosomiasis, African / epidemiology
  • Trypanosomiasis, African / genetics*
  • Trypanosomiasis, African / parasitology
  • Young Adult

Grant support

We are grateful to the University of Dschang as well as the Wellcome Trust for funding this work (099310/Z/12/Z) as part of its support for the H3Africa initiative (http://h3africa.org/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.