Background: In humans inoculated with Haemophilus ducreyi, there are host effects on the possible clinical outcomes-pustule formation versus spontaneous resolution of infection. However, the immunogenetic factors that influence these outcomes are unknown. Here we examined the role of 14 single-nucleotide polymorphisms (SNPs) in 7 selected pathogen-recognition pathways and cytokine genes on the gradated outcomes of experimental infection.
Methods: DNAs from 105 volunteers infected with H. ducreyi at 3 sites were genotyped for SNPs, using real-time polymerase chain reaction. The participants were classified into 2 cohorts, by race, and into 4 groups, based on whether they formed 0, 1, 2, or 3 pustules. χ(2) tests for trend and logistic regression analyses were performed on the data.
Results: In European Americans, the most significant findings were a protective association of the TLR9 +2848 GG genotype and a risk-enhancing association of the TLR9 TA haplotype with pustule formation; logistic regression showed a trend toward protection for the TLR9 +2848 GG genotype. In African Americans, logistic regression showed a protective effect for the IL10 -2849 AA genotype and a risk-enhancing effect for the IL10 AAC haplotype.
Conclusions: Variations in TLR9 and IL10 are associated with the outcome of H. ducreyi infection.
Keywords: Haemophilus ducreyi; chancroid; humans; immunogenetics; innate immunity; skin ulcers.
© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.