Jirawat PratoomwunPaul ThomsonKanoot JaruthamsophonRawiporn TiyasirichokchaiPimonpan JindaTicha RerkpattanapipatWichittra TassaneeyakulNontaya NakkamPawinee RerknimitrJettanong KlaewsongkramYuttana SrinoulprasertMunir PirmohamedDean J. NaisbittChonlaphat SukasemRamathibodi HospitalSiriraj HospitalChulalongkorn UniversityFaculty of Medicine, Khon Kaen UniversityUniversity of LiverpoolFaculty of Medicine Ramathibodi Hospital, Mahidol UniversityHuachiew Chalermprakiet UniversityPrince of Songkla UniversityFaculty of Medicine, Chulalongkorn University2022-08-042022-08-042021-04-29Frontiers in Immunology. Vol.12, (2021)166432242-s2.0-85106050020https://repository.li.mahidol.ac.th/handle/20.500.14594/77298HLA-B*13:01-positive patients in Thailand can develop frequent co-trimoxazole hypersensitivity reactions. This study aimed to characterize drug-specific T cells from three co-trimoxazole hypersensitive patients presenting with either Stevens-Johnson syndrome or drug reaction with eosinophilia and systemic symptoms. Two of the patients carried the HLA allele of interest, namely HLA-B*13:01. Sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones were generated from T cell lines of co-trimoxazole hypersensitive HLA-B*13:01-positive patients. Clones were characterized for antigen specificity and cross-reactivity with structurally related compounds by measuring proliferation and cytokine release. Surface marker expression was characterized via flow cytometry. Mechanistic studies were conducted to assess pathways of T cell activation in response to antigen stimulation. Peripheral blood mononuclear cells from all patients were stimulated to proliferate and secrete IFN-γ with nitroso sulfamethoxazole. All sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones expressed the CD4+ phenotype and strongly secreted IL-13 as well as IFN-γ, granzyme B and IL-22. No secretion of IL-17 was observed. A number of nitroso sulfamethoxazole-specific clones cross-reacted with nitroso dapsone but not sulfamethoxazole whereas sulfamethoxazole specific clones cross-reacted with nitroso sulfamethoxazole only. The nitroso sulfamethoxazole specific clones were activated in both antigen processing-dependent and -independent manner, while sulfamethoxazole activated T cell responses via direct HLA binding. Furthermore, activation of nitroso sulfamethoxazole-specific, but not sulfamethoxazole-specific, clones was blocked with glutathione. Sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones from hypersensitive patients were CD4+ which suggests that HLA-B*13:01 is not directly involved in the iatrogenic disease observed in co-trimoxazole hypersensitivity patients.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.3389/fimmu.2021.658593