HLA-G 3’UTR 14 Bp Insertion is Associated with a Decreased Risk of Developing Human African Trypanosomiasis in the Côte D’ivoire Population

Human African trypanosomiasis (HAT), or sleeping sickness, caused by Trypanosoma brucei gambiense, is associated with diverse clinical outcomes. Host’s genetic factors involved in immunity are potential factors that can regulate infection. Genetic polymorphisms within HLA-G could influence the level of HLA-G expression and therefore play a critical role in infection outcomes. The goal of our study was to investigate the association of 14 bp Indel HLA-G polymorphism with the susceptibility/resistance to HAT. DNA samples were collected from 119 cases, 221 controls and 43 seropositive individuals living in Ivorian HAT foci. The 14 bp Indel polymorphism was determined by PCR. Homozygous individuals for 14 bp insertion had a lower risk of progressing to active HAT (p = 0.012, OR = 0.27, 95% CI: 0.09 - 0.8). Moreover, the frequency of 14 bp insertion homozygous genotype was higher in the seropositive group (11%) than in the HAT cases group (3%) (p = 0.043, OR = 0.27, 95% CI: 0.07 - 0.99), which suggested a protective effect of 14 bp insertion homozygous genotype. Genetic polymorphisms in HLA-G may be associated with a variable risk to develop HAT. The 14 bp insertion appears to favour the occurrence of long-lasting T. b. gambiense latent infections.