An association between the levels of antigen-driven IFN-γ secretion and infection activity was indirectly confirmed when we compared IFN-γ responses in HD, TBC, and TBP with positive QFT results (i.e., in HD-QFT+, TBC-QFT+, and TBP-QFT+). The gene discussed is TBC1D1; the disease is Huntington disease.