IFNA1 and sarcoidosis: In summary, our results demonstrate that: (i) the IFN+ and IFN- TB patient groups were characterized by different signatures; (ii) the IFN- TB signature identified the IFN+ TB patient group whereas the IFN+ signature failed to diagnose the IFN- TB patient group; (iii) even though the TB IFN- signature was more stable in detecting TB patients, it failed to differentiate between IFN+ TB patient group and sarcoidosis patients.