Specifically, the hypersensitivity response in the dysregulated immune system in CF patients, in which IDO2 has a pro-inflammatory role, and the inadequate phagocytic response in patients undergone HSCT, in which IDO2 appears to be required for optimal conidiocidal activity, might account for the distinct association patterns of IDO2 SNPs with aspergillosis in the two cohorts of patients. This evidence concerns the gene IDO2 and cystic fibrosis.