Whole blood gene expression to predict susceptibility to nontuberculous mycobacterial pulmonary disease in adults with cystic fibrosis

Background: Patients with cystic fibrosis (CF) have an elevated lifetime risk of infection and disease caused by nontuberculous mycobacteria (NTM). Currently, there is no method to predict whether patients with cystic fibrosis will develop disease related to non-tuberculous mycobacteria. In non cystic fibrosis populations, several genetic susceptibility factors have been described. In this study, we examined whether patients with cystic fibrosis demonstrate a similar pattern of genetic susceptibility and explored host immune-related biomarkers predictive of NTM pulmonary disease (NTM-PD). Methods: We evaluated whole blood gene expression using bulk RNA-seq in a cohort of CF patients at the time of first isolation of NTM. Differential gene expression was compared in patients who did (n = 12) vs. did not (n= 30) develop NTM-PD following first NTM growth. Results: No differences in demographics or composition of white blood cell sample populations at the time of sample collection were identified between groups. There were no significant differences in the expression of genes previously reported to confer susceptibility to NTM-PD in non-CF populations. However, CF patients who went on to develop NTM-PD had higher expression of genes involved in the interferon (? and ?), tumor necrosis factor, and IL6 STAT3 JAK pathways. Conclusion: Patients with CF who develop NTM-PD have increased expression of genes involved in innate immunity, in contrast to non-CF populations where these responses seem to be suppressed. Overall design: RNAseq gene expression profiling in whole blood of adult patients with cystic fibrosis and infection with nontuberculous mycobacteria. Compares expression of patients who developed nontuberculous mycobacterial pulmonary disease and those who did not.