IRF8 and Mendelian susceptibility to mycobacterial diseases: The monoallelic IRF8 variant identified was therefore first viewed skeptically, as MSMD, including disseminated infection with minimally pathogenic mycobacteria like Bacillus Calmette-Guérin, was reported as a hallmark feature in cases of autosomal dominant and recessive IRF8 deficiency (18, 21).