BackgroundDespite NUDT15 variants showing significant association with thiopurine-induced adverse events (AEs) in Asians, it remains unclear which variants of NUDT15 or whether additional genetic variants should be tested to predict AEs. To clarify the best pharmacogenetic test to be used clinically, we performed association studies of NUDT15 variants and haplotypes with AEs, genome-wide association study (GWAS) to discover additional variants, and ROC analysis to select the model to predict severe AEs.MethodsOverall, 2630 patients with inflammatory bowel disease (IBD) were enrolled and genotyped for NUDT15 codon 139; 1291 patients were treated with thiopurines. diplotypes were analyzed in 970 patients, and GWASs of AEs were performed with 1221 patients using population-optimized genotyping array and imputation.ResultsWe confirmed the association of NUDT15 p.Arg139Cys with leukopenia and alopecia (p = 2.20E−63, 1.32E−69, OR = 6.59, 12.1, respectively), and found a novel association with digestive symptoms (p = 6.39E−04, OR = 1.89). Time to leukopenia was significantly shorter, and when leukopenia was diagnosed, thiopurine doses were significantly lower in Arg/Cys and Cys/Cys than in Arg/Arg. In GWASs, no additional variants were found to be associated with thiopurine-induced AEs. Despite strong correlation of leukopenia frequency with estimated enzyme activities based on the diplotypes (r2 = 0.926, p = 0.0087), there were no significant differences in the AUCs of diplotypes from those of codon 139 to predict severe AEs (AUC = 0.916, 0.921, for acute severe leukopenia, AUC = 0.990, 0.991, for severe alopecia, respectively).ConclusionsGenotyping of NUDT15 codon 139 was sufficient to predict acute severe leukopenia and alopecia in Japanese patients with IBD.Electronic supplementary materialThe online version of this article (10.1007/s00535-018-1486-7) contains supplementary material, which is available to authorized users.

Mucin depletion was shown to be a histological risk factor for clinical relapse in UC patients with MES 0.

Background/Aims: Gastrointestinal lesions of Behçet's disease (BD) are often refractory to medical therapy and sometimes result in serious comorbidities such as gastrointestinal perforation and massive bleeding. There are several reports of patients with BD comorbid with myelodysplastic syndrome (MDS) involving trisomy 8 that frequently have intestinal lesions refractory to conventional medical therapy. Little is known about the efficacy of infliximab (IFX) for these intestinal lesions. Methods: We present 2 cases of intestinal BD with MDS involving trisomy 8 who did not respond to IFX, and review previous reports of BD with MDS involving trisomy 8 concerning their responsiveness to conventional medical therapy. Results: Among 31 previously reported cases that received medical treatment for BD, 19 (61.3%) showed temporary improvement of the BD symptoms, 9 (29.0%) deteriorated, and 3 (9.7%) showed no change. All of the 9 cases that showed deterioration had intestinal lesions. Our 2 cases failed to respond to IFX, resulting in a poor prognosis. Conclusions: IFX might not be effective for improving intestinal BD comorbid with MDS involving trisomy 8. Trisomy 8 is associated with the BD prognosis and refractoriness to conventional medical therapy.