PMC

Diagnosis of dapsone hypersensitivity by skin testing and in vitro assays. A, Skin patch test results for dapsone hypersensitivity. Skin was exposed to dapsone in polyethylene glycol 200 at dilutions of 0%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 2%, and 25%. The patch tape was left to the skin for 48 h, and diagnosis was made 24 h later. Red ovals show areas of inflamed skin. B, Peripheral blood mononuclear cells (PBMC) from patients were exposed to graded concentrations of dapsone or nitroso dapsone. Proliferation was measured after 5 d by the addition of [³H]thymidine for 16 h. Results are expressed as mean ± SD cpm of triplicate cultures. A doubling of cpm in drug‐treated cultures over vehicle control is considered positive. C, PBMC from patients were exposed to optimal concentrations of dapsone or nitroso dapsone, and IFN‐γ release was visualized by ELIspot. D, PBMC from patients were exposed to graded concentrations of dapsone, nitroso dapsone, rifampicin, and clofazimine. Proliferation was measured as described in (B) (DDS, dapsone; DDS‐NO, nitroso dapsone; PHA, phytohaemagglutinin)

Proliferative response and cytokine release by dapsone‐ and nitroso dapsone‐responsive CD4⁺ and CD8⁺ clones. A, One hundred and two CD4⁺ or CD8⁺ clones were incubated with autologous antigen‐presenting cells and either dapsone (125‐500 µmol/L) or nitroso dapsone (5‐20 µmol/L) in triplicate cultures for 48 h. Proliferative responses were measured by the addition of [³H]thymidine. Results are expressed as mean ± SD cpm of the indicated number of clones. B, Detection of IFN‐γ, IL‐5, IL‐13, IL‐17, IL‐22, granzyme B, perforin, and Fas‐ligand secretion by dapsone‐ and nitroso dapsone‐responsive CD4⁺ and CD8⁺ clones. Clones were incubated with autologous antigen‐presenting cells, and either dapsone or nitroso dapsone and cytokine release was visualized by ELIspot. C, Representative ELIspot images showing the cytokines released by dapsone and nitroso dapsone‐responsive CD8⁺ clones

Cross‐reactivity of dapsone‐ and nitroso dapsone‐responsive T‐cell clones. Dapsone‐ and nitroso dapsone‐responsive CD4⁺ and CD8⁺ clones were cultured with irradiated autologous EBV‐transformed B cells and either dapsone (100‐500 µmol/L) or the nitroso metabolite (5‐20 µmol/L) in triplicate cultures for 48 h. T‐cell proliferative responses were assessed through the addition of [³H]‐thymidine. A, Mean cross‐reactivity data for 153 clones divided according to the drug antigen peripheral blood mononuclear cells were cultured with to generate clones and CD phenotype. B, Pie charts showing number of clones with a particular cross‐reactivity profile (compound specific, weekly cross‐reactive (cross‐reactive compound displaying 10%‐50% response detected with comparator) and strongly cross‐reactive (cross‐reactive compound displaying > 50% response detected with comparator). C, Representative clones displaying each response profile. D, Relative quantification of dapsone and azoxy dimer in cultures containing nitroso dapsone (30 µmol/L), autologous EBV‐transformed B cells, and T‐cell clones. E, Absolute quantification of dapsone formation in cultures containing nitroso dapsone (30 µmol/L), autologous EBV‐transformed B cells, and T‐cell clones. Left hand graph shows the standard curve for dapsone (concentration range: 5 nmol/L‐1 µmol/L). Right hand side graph shows the time‐dependent formation of dapsone [Colour figure can be viewed at wileyonlinelibrary.com]

T-test results for Alzheimer’s disease prevalence and DDS prescription rates
We used the data normalization technique to analyze Alzheimer’s disease (AD) prevalence and the DDS prescription (+)/non-prescription (−) group from January 2007 to June 2020 as T1: DDS(+)/AD(+), T2: DDS(+)/AD (−), T3: DDS(−)/AD (+), and T4: DDS(−)/AD(−). The participants with T1 (M = 0.1766, SD = 0.074) were compared to those with T2 (M = 0.5501, SD = 0.1421). T1:T2 in the group taking Dapsone also demonstrated that the group with AD and the group without AD were distinguished. We compared T3 (M = 0.1766, SD = 0.074) and T4 (M = 0.5501, SD = 0.1421). T3:T4 in the group not taking Dapsone also demonstrated that the group with AD and without AD was distinguished. The participants with T1 (M = 0.1766, SD = 0.074) were compared to those with T3 (M = 0.1766, SD = 0.074). The T1:T3 test proved that the incidence of AD was significantly reduced by dapsone. The participants with T2 disease (M = 0.5501, SD = 0.1421) were compared to those with T3 disease (M = 0.1766, SD = 0.074). The T2:T3 test proved that the prevalence of AD is significantly high without dapsone, and the proportion of HD patients without AD is increased with dapsone. The participants with T1 (M = 0.1766, SD = 0.074) were compared to T4 (M = 0.5501, SD = 0.1421). The T1:T4 test demonstrated that the trend was similar for patients with DDS (+)/AD (+) and DDS (−)/AD (−). This demonstrates that HD patients also develop AD but at a significantly lower rate when taking dapsone. Fewer people who do not develop AD without taking dapsone suggest that there is a clear distinction between the group taking dapsone and the group not taking dapsone.