Human-inherited RORγT Deficiency Encompasses Genetic Heterogeneity, T Cell Deficiency, and Clinical Homogeneity

We previously reported inherited RORγT deficiency in seven patients from three ancestries (Chilean, Palestinian, Saudi Arabian) with mycobacterial disease and chronic mucocutaneous candidiasis (CMC). We report here five additional patients from different ancestries (Afghan, Indian, Iranian, Japanese, Sri Lankan), each homozygous for a new loss-of-function RORC variant. All but one patient - the exception receiving early prophylaxis - developed mycobacterial disease due to a near-complete depletion of innate-like adaptive T cells, including MAIT and iNKT cells, low counts of adaptive TH1* and CD8+ T cells, and impaired Mycobacterium-induced IFN-γ production by the remaining cells of these subsets, NK cells, conventional CD4+ T, Vδ1, and Vδ2 γδT cells. Most patients also displayed CMC due to their low counts of TH17 and TH1* cells. One patient died from disseminated Bacille Calmette-Guérin (BCG) vaccine infection, but, unexpectedly, all the other patients are still alive and clinically stable. RORγT is essential for protective immunity against mycobacteria and Candida in humans.