IRF8 and Mendelian susceptibility to mycobacterial diseases: The first IRF8 deficiency patient reported had biallelic variants leading to disseminated BCG (Mendelian Susceptibility to Mycobacterial Disease (MSMD), and fungal infections (18, 19) They had deficient monocytes and dendritic cells with failure to produce either IL-12 or IFN- γ upon LPS stimulation (13, 20).