Dectin-1 and DC-SIGN Polymorphisms Associated with Invasive Pulmonary Aspergillosis Infection

The recognition of pathogen-derived structures by C-type lectins and the chemotactic activity mediated by the CCL2/CCR2 axis are critical steps in determining the host immune response to fungi. The present study was designed to investigate whether the presence of single nucleotide polymorphisms (SNPs) within DC-SIGN, Dectin-1, Dectin-2, CCL2 and CCR2 genes influence the risk of developing Invasive Pulmonary Aspergillosis (IPA). Twenty-seven SNPs were selected using a hybrid functional/tagging approach and genotyped in 182 haematological patients, fifty-seven of them diagnosed with proven or probable IPA according to the 2008 EORTC/MSG criteria. Association analysis revealed that carriers of the Dectin-1 (rs3901533 T/T) and Dectin-1 (rs7309123 G/G) genotypes and DC-SIGN (rs4804800 G), DC-SIGN (rs11465384 T), DC-SIGN (7248637 A) and DC-SIGN (7252229 C) alleles had a significantly increased risk of IPA infection (OR = 5. 59 95%CI 1. 37-22. 77; OR = 4. 91 95%CI 1. 52-15. 89; OR = 2. 75 95%CI 1. 27-5. 95; OR = 2. 70 95%CI 1. 24-5. 90; OR = 2. 39 95%CI 1. 09-5. 22 and OR = 2. 05 95%CI 1. 00-4. 22, respectively). There was also a significantly increased frequency of galactomannan positivity among patients carrying the Dectin-1 (rs3901533T) allele and Dectin-1 (rs7309123G/G) genotype. In addition, healthy individuals with this latter genotype showed a significantly decreased level of Dectin-1 mRNA expression compared to C-allele carriers, suggesting a role of the Dectin-1 (rs7309123) polymorphism in determining the levels of Dectin-1 and, consequently, the level of susceptibility to IPA infection. SNP-SNP interaction (epistasis) analysis revealed significant interactions models including SNPs in Dectin-1, Dectin-2, CCL2 and CCR2 genes, with synergistic genetic effects. Although these results need to be further validated in larger cohorts, they suggest that Dectin-1, DC-SIGN, Dectin-2, CCL2 and CCR2 genetic variants influence the risk of IPA infection and might be useful in developing a risk-adapted prophylaxis.