Metabolic and Chemical Origins of Cross-Reactive Immunological Reactions to Arylamine Benzenesulfonamides: T-Cell Responses to Hydroxylamine and Nitroso Derivatives

Abstract

Exposure to sulfamethoxazole (SMX) is associated with T-cell-mediated hypersensitivity reactions in human patients. T-cells can be stimulated by the putative metabolite nitroso SMX, which binds irreversibly to protein. The hydroxylamine and nitroso derivatives of three arylamine benzenesulfonamides, namely, sulfamethozaxole, sulfadiazine, and sulfapyridine, were synthesized, and their T-cell stimulatory capacity in the mouse was explored. Nitroso derivatives were synthesized by a three-step procedure involving the formation of nitro and hydroxylamine sulfonamide intermediates. For immune activation, female Balb-c strain mice were administered nitroso sulfonamides four times weekly for 2 weeks. After 14 days, isolated splenocytes were incubated with the parent compounds, hydroxylamine metabolites, and nitroso derivatives to measure antigen-specific proliferation. To explore the requirement of irreversible protein binding for spleen cell activation, splenocytes were incubated with nitroso derivatives in the presence or absence of glutathione. Splenocytes from nitroso sulfonamide-sensitized mice proliferated and secreted interleukin (IL)-2, IL-4, IL-5, and granulocyte monocyte colony-stimulating factor following stimulation with nitroso derivatives but not the parent compounds. Splenocytes from sensitized mice were also stimulated to proliferate with hydroxylamine and nitroso derivatives of the structurally related sulfonamides. The addition of glutathione inhibited the nitroso-specific T-cell response. Hydroxylamine metabolites were unstable in aqueous solution: Spontaneous transformation yielded appreciable amounts of nitroso and azoxy compounds as well as the parent compounds within 0.1 h. T-cell cross-reactivity with nitroso sulfonamides provides a mechanistic explanation as to why structurally related arylamine benzenesulfonamides are contraindicated in hypersensitive patients.

Drug Antigenicity, Immunogenicity, and Costimulatory Signaling: Evidence for Formation of a Functional Antigen through Immune Cell Metabolism

“…Auto-oxidation generates SMX-NO, self-conjugation generates azo and azoxy dimers, and reduction through enzymatic reactions or glutathione-dependent processes liberates a hydroxylamine and the parent drug ( Fig. 1) (26,34,(40)(41)(42)(43). Although these reactions result in rapid (within 5 min) and complete degradation of SMX-NO, multiple meta-stable protein adducts that become internalized via a caveole-dependent mechanism (16,44,45) are readily detectable.…”

“…Previous studies using lymphocytes from SMX-hypersensitive patients and animal models of SMX immunogenicity demonstrated that Ag-stimulated T cells secrete high levels of the Th2 cytokine IL-5 and the Th1 cytokine IFN-g (41,47,48). Data presented in the current study using multiplex methods and cloned T cells confirm these initial reports.…”

Sulfa Allergy and Therapeutic Decisions

“…4 The antibiotic group includes the sulfonarylamine antibiotics, such as sulfanilamide, sulfoxazole, and sulfamylon. 1,4,5,6 These antibiotics are structurally related with the sulfonamide moiety directly connected to a benzene ring, an amine (-NH 2 ) structure at the N4 position, and an aromatic ring at the N1 position. 1,5,6,7 It is a metabolite of the sulfonarylamines that is antigenic and elicits T-cell and IgE immunemediated reactions.…”

“…1,4,5,6 These antibiotics are structurally related with the sulfonamide moiety directly connected to a benzene ring, an amine (-NH 2 ) structure at the N4 position, and an aromatic ring at the N1 position. 1,5,6,7 It is a metabolite of the sulfonarylamines that is antigenic and elicits T-cell and IgE immunemediated reactions. 1,5,6 The second class, non-sulfonarylamines or sulfonamide non-antibiotics, include the carbonic anhydrase inhibitors, sulfonylureas, loop diuretics, thiazide diuretics, COX-2 inhibitors, and protease inhibitors.…”

“…1,5,6,7 It is a metabolite of the sulfonarylamines that is antigenic and elicits T-cell and IgE immunemediated reactions. 1,5,6 The second class, non-sulfonarylamines or sulfonamide non-antibiotics, include the carbonic anhydrase inhibitors, sulfonylureas, loop diuretics, thiazide diuretics, COX-2 inhibitors, and protease inhibitors. These non-sulfonarylamines lack the amine structure at the N4 position.…”