The data described by Naser et al in this recent paper suggest that genetic polymorphisms may play vital role in T-cell regulation, susceptibility to mycobacteria and ultimately response to treatment. This is the first study to report the detection of MAP DNA in the blood of RA patients; further studies are needed using larger number of samples.
https://www.frontiersin.org/articles/10.3389/fcimb.2018.00011/abstract