STAT4 and Granuloma: Moreover, mice deficient in TNF (48, 49, 75–79), IFN-γ (80), IL-12 (81), signal transducer and activator of transcription 4 (STAT4) (82), and myeloid differentiation primary-response protein 88 (MYD88) (83–85) had poorly formed granulomas and were highly susceptible to Mtb infection, thus, giving more credibility to the host-protective nature of granulomas.