“…A long list of associations between certain medical conditions and the occurrence of NTM disease has been appreciated for many years and may reflect heightened susceptibility to NTM although the mechanism(s) by which this might occur generally remains obscure. This list includes: an array of preexisting structural lung diseases such as resulting from prior pulmonary tuberculosis, cystic fibrosis and other forms of bronchiectasis [48], chronic obstructive pulmonary disease (COPD), silicosis and other pneumoconiosis, conditions that might alter local or systemic host immune status ranging from alcoholism and smoking, esophageal reflux (especially with M. fortuitum/abscessus) [49], or sinus disease [50], to profound systemic alterations of innate or acquired immunity from IFN-γ production or receptor abnormalities or compromise from immune suppressing drugs and organ transplantation [40]. Interestingly, advanced HIV/AIDS, which has a clear association with systemic MAC, is much less frequently associated with PNTM particularly in patients receiving anti-retroviral therapy [51].…”