Long-term efficacy and tolerability of dose-adjusted thiopurine treatment in maintaining remission in inflammatory bowel disease patients with NUDT15 heterozygosity

Background/Aims

Thiopurines are key drugs for inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD). Recently, NUDT15 polymorphism (R139C, c.415C > T) has been shown to be associated with thiopurine-induced adverse events in Asian populations. In patients with the C/T genotype, low-dose thiopurine treatment is recommended, but its long-term efficacy and tolerability remain unclear. This study aimed to uncover the long-term efficacy and appropriate dosage of thiopurine for IBD patients with the C/T genotype.

Methods

A total of 210 patients with IBD (103 UC and 107 CD) determined to have NUDT15 R139C variants were enrolled. Clinical data were retrospectively reviewed from medical records.

Results

Of 46 patients (21.9%) with the C/T genotype, 30 patients (65.2%) were treated with thiopurines. Three of whom (10.0%) discontinued thiopurine treatment due to adverse events and 27 of whom continued. The median maintenance dosage of 6-mercaptopurine was 0.25 mg/kg/day (range, 0.19–0.36 mg/kg/day), and 6-thioguanine nucleotides level was 230 (104–298) pmol/8 × 10⁸ red blood cells. Cumulative thiopurine continuation rates for 120 months for patients with the C/C and C/T genotypes were not significantly different (P = 0.895). Cumulative non-relapse rates in the patients with UC treated with thiopurine monotherapy and surgery-free rates in CD patients treated with combination therapy (thiopurines and anti-tumor necrosis factor-α agents) for maintenance remission were not significantly different at 60 months (C/C vs. C/T, P = 0.339 and P = 0.422, respectively).

Conclusions

Low-dose thiopurine treatment is an effective and acceptable treatment for patients with C/T genotype.

Successful recovery from coronavirus disease 2019 in a living kidney transplant recipient using low-dose methylprednisolone

Introduction

The data of immunosuppressive therapy management on solid organ transplant recipients with coronavirus disease 2019 are insufficient. We report a kidney transplant recipient who developed coronavirus disease 2019 pneumonia, with successful management of low-dose mPSL.

Case presentation

A 36-year-old man, who underwent living kidney transplantation 1.5 year prior, developed fever. After 10 days, he developed dyspnea, and his blood oxygen levels decreased. Computed tomography showed pulmonary ground-glass shadow on both lungs, and the coronavirus disease 2019 real-time polymerase chain reaction test was positive. After reducing the immunosuppressive agents, the C-reactive protein levels continued elevating, and the pulmonary shadow spread. Subsequently, low-dose methylprednisolone (40 mg/day) was administered for 4 days and his C-reactive protein and blood oxygen levels increased and improved, respectively. The coronavirus disease 2019 real-time polymerase chain reaction test was negative and the pulmonary shadow disappeared.

Conclusion

Low-dose methylprednisolone may prevent the development of severe coronavirus disease 2019.

Significance of revised criteria for chronic active T cell-mediated rejection in the 2017 Banff classification: Surveillance by 1-year protocol biopsies for kidney transplantation

Diagnostic criteria for chronic active T cell-mediated rejection (CA-TCMR) were revised in the Banff 2017 consensus, but it is unknown whether the new criteria predict graft prognosis of kidney transplantation. We enrolled 406 kidney allograft recipients who underwent a 1-year protocol biopsy (PB) and investigated the diagnostic significance of Banff 2017. Interobserver reproducibility of the 3 diagnosticians showed a substantial agreement rate of 0.68 in Fleiss's kappa coefficient. Thirty-three patients (8%) were classified as CA-TCMR according to Banff 2017, and 6 were previously diagnosed as normal, 12 as acute TCMR, 10 with borderline changes, and 5 as CA-TCMR according to Banff 2015 criteria. Determinant factors of CA-TCMR were cyclosporine use (vs tacrolimus), previous acute rejection, and BK polyomavirus-associated nephropathy. In survival analysis, the new diagnosis of CA-TCMR predicted a composite graft endpoint defined as doubling serum creatinine or death-censored graft loss (log-rank test, P < .001). In multivariate analysis, CA-TCMR was associated with the second highest risk of the composite endpoint (hazard ratio: 5.42; 95% confidence interval, 2.02-14.61; P < .001 vs normal) behind antibody-mediated rejection. In conclusion, diagnosis of CA-TCMR in Banff 2017 may facilitate detecting an unfavorable prognosis of kidney allograft recipients who undergo a 1-year PB.

Correction to: Total nephroureterocystectomy and urethrectomy due to urothelial carcinoma associated with the BK polyomavirus infection after kidney transplantation: a case report with literature review

An amendment to this paper has been published and can be accessed via the original article.

Cumulative cancer incidence and mortality after kidney transplantation in Japan: A long-term multicenter cohort study

Kidney transplantation is the most promising treatment to improve mortality and life quality in end‐stage kidney disease; however, cancer remains a leading cause of death. Several factors including immunosuppressants might be associated with a gradual increase in cumulative cancer incidence after kidney transplantation. Risk factors for cancer and overall and cancer‐specific survival were analyzed in 1973 kidney transplant recipients from three study institutions in Japan. The 5‐, 10‐, 20‐, and 30‐year overall and cancer‐specific survival rates were 93.3%, 88.4%, 78.0%, and 63.6% and 99.4%, 98.0%, 95.3%, and 91.7%, respectively. The overall survival rate was significantly higher and the graft survival rate was significantly lower in recipients without cancer than in those with cancer. Older recipient age, longer dialysis duration before kidney transplantation, and history of transfusion were significant predictors of cancer. Dialysis duration before kidney transplantation was a prognostic factor of overall survival rate. Regarding cancer‐specific survival rates, older recipient age and dialysis duration before kidney transplantation were prognostic factors of worse cancer‐specific survival rates. The type of immunosuppressant was not associated with an increased cancer rate. Aggressiveness of immunosuppressant regimens or potent immunosuppressants might improve graft survival rate while inducing de novo cancer after kidney transplantation. Older age and longer dialysis duration before kidney transplantation were risk factors of cancer‐specific survival rate.

Prognostic impact of sarcopenia in patients with metastatic hormone-sensitive prostate cancer

BACKGROUND

Cancer cachexia is associated with a poor prognosis. This study aimed to investigate the association between sarcopenia and survival in patients with metastatic hormone-sensitive prostate cancer.

METHODS

We retrospectively evaluated 197 patients diagnosed with metastatic hormone-sensitive prostate cancer in our department and its affiliated institution between January 2008 and December 2015. Sarcopenia was diagnosed according to the sex-specific consensus definition. Castration-resistance prostate cancer-free survival, cancer-specific survival and overall survival from the metastatic hormone-sensitive prostate cancer diagnoses were calculated using the Kaplan-Meier method and compared using the log-rank test. Risk factors affecting the survival outcomes were analyzed using the Cox proportional regression analysis.

RESULTS

In total, 163 patients (82.7%) had sarcopenia. Cancer-specific survival and overall survival were significantly shorter in sarcopenic patients than in non-sarcopenic patients (median cancer-specific survival: 77.0 months vs. not reached, P = 0.0099; overall survival: 72.0 months vs. not reached, P = 0.0465), whereas castration-resistance prostate cancer-free survival did not significantly differ between the groups (P = 0.6063). Multivariate analyses showed that sarcopenia was an independent factor for cancer-specific survival (hazard ratio: 2.18, P = 0.0451), together with the Gleason score (hazard ratio: 1.87, P = 0.0272) and LATITUDE risk classification (hazard ratio: 2.73, P = 0.0008). Moreover, the prognostic association of sarcopenia was remarkable in patients aged <73.0 years (cancer-specific survival: 82.0 months vs. not reached, P = 0.0027; overall survival: 72.0 months vs. not reached, P = 0.0078 in sarcopenic vs. non-sarcopenic patients), whereas the association was not significant in patients aged ≥73.0 years (cancer-specific survival: 76.0 and 75.0 months, respectively, P = 0.7879; overall survival: 67.0 and 52.0 months, respectively, P = 0.7263).

CONCLUSION

Sarcopenia was an independent risk factor of cancer-specific survival in patients with metastatic hormone-sensitive prostate cancer, especially in younger patients.

TL1A (TNFSF15) genotype affects the long-term therapeutic outcomes of anti-TNFα antibodies for Crohn's disease patients

Background and Aim

TL1A (TNFSF15) is a major Crohn's disease (CD) susceptibility gene, especially in the East Asian population, and is also known to be associated with some clinical phenotypes, such as stricturing and penetrating behavior. This study aims to investigate the association between TL1A genotype and the long‐term therapeutic outcomes of infliximab and adalimumab in Japanese CD patients.

Methods

We investigated 119 biologic‐naïve CD patients treated with infliximab or adalimumab. TL1A ‐358C/T (rs6478109) was genotyped as a tag single nucleotide polymorphism (SNP) for CD risk or nonrisk haplotype of TL1A (the ‐358C allele is a risk allele for CD development). We compared the long‐term therapeutic outcomes of anti‐tumor necrosis factor (TNF) antibodies between the TL1A ‐358C/C group and the C/T+T/T group.

Results

Sixty‐nine cases (58.0%) were homozygous for the risk allele (TL1A ‐358C/C group), and 50 cases (42.0%) were heterozygous for the risk allele or homozygous for the protective allele (TL1A ‐358C/T+T/T group). No significant differences were found in the cumulative retention rates and the relapse‐free survival between the TL1A genotypes. However, the surgery‐free survival was significantly lower in the TL1A ‐358C/C group than in the C/T+T/T group (log‐rank test, P < 0.05). Multivariate analysis showed that TL1A ‐358C/C was identified as an independent risk factor for surgery (hazard ratio, 4.67; 95% confidence interval, 1.39–22.1; P = 0.025).

Conclusion

An association was found between the TL1A genotype and the therapeutic outcomes of anti‐TNF therapy. Our data indicate that the design of customized therapy with anti‐TNF antibodies using TL1A genomic information could be effective in the future.

Genetic Analysis of Ulcerative Colitis in Japanese Individuals Using Population-specific SNP Array

BACKGROUND

To clarify the genetic background of ulcerative colitis (UC) in the Japanese population, we conducted a genome-wide association study (GWAS) using a population-specific single nucleotide polymorphism (SNP) array.

METHODS

We performed a GWAS and replication study including 1676 UC patients and 2381 healthy controls. The probability of colectomy was compared between genotypes of rs117506082, the top hit SNP at HLA loci, by the Kaplan-Meier method. We studied serum expression of miR-622, a newly identified candidate gene, from 32 UC patients and 8 healthy controls by quantitative reverse-transcription polymerase chain reaction.

RESULTS

In the GWAS, only the HLA loci showed genome-wide significant associations with UC (rs117506082, P = 6.69E-28). Seven nominally significant regions included 2 known loci, IL23R (rs76418789, P = 6.29E-7) and IRF8 (rs16940202, P = 1.03E-6), and 5 novel loci: MIR622 (rs9560575, P = 8.23E-7), 14q31 (rs117618617, P = 1.53E-6), KAT6B (rs12260609, P = 1.81E-6), PAX3-CCDC140-SGPP2 (rs7589797, P = 2.87E-6), and KCNA2 (rs118020656, P = 4.01E-6). Combined analysis revealed that IL23R p.G149R (rs76418789, P = 9.03E-11; odds ratio [OR], 0.51) had genome-wide significant association with UC. Patients with GG genotype of rs117506082 had a significantly lower probability of total colectomy than those with the GA+AA genotype (P = 1.72E-2). Serum expression of miR-622 in patients with inactive UC tended to be higher than in healthy controls and patients with active UC (inactive UC vs healthy controls, P = 3.03E-02; inactive UC vs active UC, P = 6.44E-02).

CONCLUSIONS

IL23R p.G149R is a susceptibility locus for UC in Japanese individuals. The GG genotype of rs117506082 at HLA loci may predict a better clinical course.

Rare Genotype of His/His in NUDT15 Codon 139 and Thiopurine-associated Adverse Events in a Case of Ulcerative Colitis

Thiopurine drugs are commonly used to treat immunologic diseases. However, the narrow therapeutic safety margin demands evidence-based precision medicine approaches. NUDT15 variants are associated with thiopurine-induced adverse events, particularly in Asians. We herein report a rare genotype of His/His in NUDT15 codon 139 in a case of ulcerative colitis and review the relevant literature. The patient experienced severe thiopurine-associated adverse events, including leukopenia and alopecia. There is no literature on the His/His genotype in NUDT15 codon 139, and our case suggests cautious use or the contraindication of thiopurines for patients with this genotype.

Variants That Affect Function of Calcium Channel TRPV6 Are Associated With Early-Onset Chronic Pancreatitis

BACKGROUND & AIMS

Changes in pancreatic calcium levels affect secretion and might be involved in development of chronic pancreatitis (CP). We investigated the association of CP with the transient receptor potential cation channel subfamily V member 6 gene (TRPV6), which encodes a Ca²⁺-selective ion channel, in an international cohort of patients and in mice.

METHODS

We performed whole-exome DNA sequencing from a patient with idiopathic CP and from his parents, who did not have CP. We validated our findings by sequencing DNA from 300 patients with CP (not associated with alcohol consumption) and 1070 persons from the general population in Japan (control individuals). In replication studies, we sequenced DNA from patients with early-onset CP (20 years or younger) not associated with alcohol consumption from France (n = 470) and Germany (n = 410). We expressed TRPV6 variants in HEK293 cells and measured their activity using Ca²⁺ imaging assays. CP was induced by repeated injections of cerulein in TRPV6^mut/mut mice.

RESULTS

We identified the variants c.629C>T (p.A210V) and c.970G>A (p.D324N) in TRPV6 in the index patient. Variants that affected function of the TRPV6 product were found in 13 of 300 patients (4.3%) and 1 of 1070 control individuals (0.1%) from Japan (odds ratio [OR], 48.4; 95% confidence interval [CI], 6.3-371.7; P = 2.4 × 10^-8). Twelve of 124 patients (9.7%) with early-onset CP had such variants. In the replication set from Europe, 18 patients with CP (2.0%) carried variants that affected the function of the TRPV6 product compared with 0 control individuals (P = 6.2 × 10^-8). Variants that did not affect the function of the TRPV6 product (p.I223T and p.D324N) were overrepresented in Japanese patients vs control individuals (OR, 10.9; 95% CI, 4.5-25.9; P = 7.4 × 10^-9 for p.I223T and P = .01 for p.D324N), whereas the p.L299Q was overrepresented in European patients vs control individuals (OR, 3.0; 95% CI, 1.9-4.8; P = 1.2 × 10^-5). TRPV6^mut/mut mice given cerulein developed more severe pancreatitis than control mice, as shown by increased levels of pancreatic enzymes, histologic alterations, and pancreatic fibrosis.

CONCLUSIONS

We found that patients with early-onset CP not associated with alcohol consumption carry variants in TRPV6 that affect the function of its product, perhaps by altering Ca²⁺ balance in pancreatic cells. TRPV6 regulates Ca²⁺ homeostasis and pancreatic inflammation.

Robot-Assisted Radical Cystectomy With Orthotopic Neobladder as a Urinary Diversion for a Kidney Transplant Recipient: A Case Report

BACKGROUND

A higher prevalence of bladder cancer is reported in solid organ recipients, and advanced cancer requires radical cystectomy combined with urinary diversion. Surgery is technically challenging in kidney transplant recipients because of urinary tract abnormalities. Here, we describe the use of a robot-assisted approach in a kidney transplant recipient.

CASE PRESENTATION

The etiology of the patient's end-stage renal disease was bilateral hypoplastic kidney. The patient started to receive hemodialysis at 19 years of age and underwent living-related kidney transplant at 23 years of age. Thirteen years later, he was diagnosed with invasive urothelial carcinoma and underwent robot-assisted radical cystectomy with extracorporeal neobladder construction under open laparotomy. Surgery was indicated to enhance suture flexibility and dissection of the peribladder tissues. Although the patient had an intraperitoneal infection caused by leakage from the vesicourethral anastomosis site and required drainage of the abscess, his condition stabilized after antibiotic treatment.

CONCLUSION

This case outlines the effectiveness of the robot-assisted approach in patients with urinary tract abnormalities, such as kidney transplant recipients.

Repertoire analysis of memory T-cell receptors in Japanese patients with inflammatory bowel disease

Background and Aim

The T‐cell receptor (TCR) repertoire was assessed in response to various antigens and was considered to be associated with the pathogenesis of inflammatory bowel disease (IBD). Thus, we performed TCR repertoire analysis to examine the pathology of IBD from changes in the TCR repertoire of memory T cells in the intestinal lamina propria mononuclear cells (LPMCs) and peripheral blood mononuclear cells (PBMCs) of patients with IBD.

Methods

LPMCs in the surgical specimens and PBMCs were isolated from 12 patients with IBD (5 patients with ulcerative colitis [UC] and 7 patients with Crohn's disease [CD]). PBMCs were collected from 10 healthy individuals as controls. Comprehensive TCR sequence analyses of adaptor‐ligation polymerase chain reaction (PCR) products were performed using MiSeq.

Results

The diversity of TCR‐α and TCR‐β in PBMCs was significantly lower in patients with IBD than that in controls (P = 0.00084 and 0.0013, respectively). Comparisons of TCR diversity in LPMCs and PBMCs between CD and UC showed that the diversity in LPMC was not affected by diseases, whereas that in PBMCs was significantly lower in CD than in UC (P = 0.045 and 0.049, respectively). Some TCR clones may have shown a specific increase or decrease in CD and UC, and many clones were common to both LPMCs and PBMCs in the same patients.

Conclusion

The diversity of TCR clones in LPMCs and PBMCs in patients with IBD was significantly lower than that of PBMCs in controls. TCR diversity in PBMCs was particularly low in patients with CD.

Serum C-reactive protein and albumin are useful biomarkers for tight control management of Crohn's disease in Japan

Tight control management of Crohn’s disease (CD) based on biomarkers is more effective than conventional clinical management; however, fecal calprotectin is not allowed in Asian and some Western countries. To investigate whether tight control management based on readily available serum biomarkers results in better outcomes, we retrospectively reviewed treatment courses of consecutive Japanese CD patients treated with anti-tumor necrosis factor agents between 2003 and 2018. The association between failure of tight control (C-reactive protein (CRP) ≥ 0.5 mg/dL or albumin (Alb) < 3.8 g/dL at week 8 or 24) and subsequent major adverse outcomes (MAOs; hospitalization related to CD worsening, surgery, and discontinuation due to treatment failure) were analyzed. Among 223 patients followed for >8 weeks, 88 patients experienced MAOs. Multivariate analysis identified penetrating type, CRP ≥ 0.5 mg/dL and Alb < 3.8 g/dL at week 8 as independent risk factors (hazard ratios: 2.16, 2.06, and 2.08, respectively). Among 204 patients followed for >24 weeks, 80 patients experienced MAOs. Penetrating type, CRP ≥ 0.5 mg/dL, and Alb < 3.8 g/dL at week 24 were identified as independent risk factors (2.39, 1.90, and 2.20, respectively). Even in settings without fecal calprotectin, tight control management based on serum CRP and Alb may help avoid MAOs.

Endoscopic radial incision and cutting for Crohn's Disease-associated intestinal stricture: a pilot study

Background and study aims  Intestinal stricture associated with Crohn's disease (CD) is usually treated by endoscopic balloon dilation (EBD) or stricture plasty. Although EBD is effective and safe for such strictures, refractory stricture after EBD poses a problem. Hence, other novel approaches for these refractory strictures are required. On the other hand, the efficacy of radial incision and cutting (RIC) method for esophageal stricture after esophagogastric surgery is reported. In this pilot study, we adopted the RIC technique for five CD patients with refractory intestinal stricture to dilate their strictures. We conducted the RIC procedure using an electric needle knife with a ceramic tip on the top of the needle. Four cases were of anastomotic stricture after ileocecal resection and the remaining one case was of stricture due to mucosal healing. The RIC procedure was successful for all five patients. Average procedure time was 18.6 minutes. One patient developed delayed bleeding after RIC. There were no cases of perforation. RIC could be an alternative therapy for intestinal stricture associated with CD. Further studies should be conducted to clarify its efficacy and safety.

Correction to: High-resolution melt analysis enables simple genotyping of complicated polymorphisms of codon 18 rendering the NUDT15 diplotype

The correct name of the last author should be.

High-resolution melt analysis enables simple genotyping of complicated polymorphisms of codon 18 rendering the NUDT15 diplotype

BACKGROUND

The genetic variants of NUDT15 have been verified to induce adverse events (AEs) of thiopurines. Codon 139 variants are frequently observed in Asians, while multiple variants are seen in codon 18 which also cause AEs including the European ancestry. The purpose of this study is to establish a technique capable of the simple genotyping of NUDT15 codon 18 and to evaluate its efficacy.

METHODS

A high-resolution melt (HRM) technique is performed to simply determine genotypes. The accuracy of HRM analysis was evaluated with DNAs from 1245 Japanese patients with inflammatory bowel diseases. Subsequently, another group of 572 patients was analyzed to verify the method. The diplotypes and the frequency of their AEs were estimated on the basis of codon 18 and 139 genotypes.

RESULTS

The HRM analysis enabled the correct identification of the three main genotypes, ref/ref, ref/ins, and ref/V18I, in 1236 of 1241 cases. All rare genotypes including ref/del were identified as the impossible-to-determine group, the proper diagnosis rate was 99.6%. In the verification test using other samples, the diagnosis rate was 99.7%. By estimating diplotypes using both codon 18 and 139 genotypes, 2.74% and 2.13% of Japanese patients with Arg/Arg and Arg/Cys of codon 139 have a lower enzymatic activity of NUDT15 and a higher risk for adverse responses than those estimated by codon 139 genotypes alone.

CONCLUSIONS

Our study showed that HRM method enables simple genotyping of complicated codon 18 variants essential to haplotype estimation of the NUDT15.

Possible abscopal effect in urothelial carcinoma of the upper urinary tract after treatment with immune checkpoint inhibitors

INTRODUCTION

Regression of non-irradiated metastatic lesions after radiation therapy is known as the abscopal effect. We report a case of urothelial carcinoma in which the abscopal effect was possibly observed after immune checkpoint inhibitor administration.

CASE PRESENTATION

A 68-year-old woman diagnosed with left renal pelvic cancer underwent total nephroureterectomy and regional lymph node dissection. Eight months later, imaging studies detected local recurrence and paraaortic lymph node metastasis. The tumor progressed despite cisplatin + gemcitabine, pembrolizumab, and gemcitabine + docetaxel therapy. Radiation therapy was administered to a painful back lesion, which resulted in dramatic symptom relief. Computed tomography 2 months after radiation therapy indicated reduced size of the irradiated lesion and some non-irradiated lymph nodes.

CONCLUSION

Combined radiation therapy and immune checkpoint inhibitors can provide additional benefits for certain cancers, possibly due to negative immunomodulatory response blockade. Thus, this combined therapy may be a new metastatic urothelial carcinoma treatment strategy.

Long-Term Prognosis of Japanese Patients with Crohn's Disease Treated by Switching Anti-Tumor Necrosis Factor-α Antibodies

Introduction

The long-term prognosis of Japanese patients with Crohn's disease (CD) treated by switching anti-tumor necrosis factor-α (anti-TNFα) antibodies remains unclear.

Objective

This study aimed to clarify the long-term prognosis and clinical factors that affect the long-term prognosis and outcomes of such patients.

Methods

This retrospective, observational, single-center cohort study analyzed Japanese patients with CD treated by switching between infliximab and adalimumab in the Tohoku University Hospital between March 2003 and December 2017. Cumulative relapse-free survival and cumulative surgery-free survival rates were analyzed using the Kaplan-Meier method. Clinical factors that affected the long-term outcomes were identified using both a log-rank test and the Cox proportional hazards model.

Results

The cumulative relapse-free survival rates were 68.6, 33.7, and 22.9% at 1, 3, and 5 years, respectively. The surgery-free survival rates were 91.7, 75.7, and 57.4% at 1, 3, and 5 years, respectively. The cumulative relapse-free survival rate was significantly higher in the group with ileal lesions (HR = 0.12; 95% CI 0.0066-0.64, p = 0.0086), stricture (HR = 0.24; 95% CI 0.0094-0.59, p = 0.0021), and a penetrating type (HR = 0.34; 95% CI 0.14-0.84, p = 0.020). Intolerance (HR = 0.29; 95% CI 0.12-0.63, p = 0.0013) and switching after surgery (HR = 0.41; 95% CI 0.17-0.87, p = 0.019) were clinical factors that reduced the risk of recurrence. The cumulative surgery-free survival rate was significantly higher in the group that switched after surgery (HR = 0.28; 95% CI 0.074-0.91, p = 0.034) and used concomitant thiopurine (HR = 0.32; 95% CI 0.10-0.90, p = 0.030).

Conclusion

We should clarify the reason for switching anti-TNFα antibodies and investigate bowel complications before switching. Surgical reset of bowel complications including stricture and fistula could reduce the risk of recurrence after switching anti-TNFα antibodies. Concomitant thiopurine administration might reduce the risk of bowel surgery after switching anti-TNFα antibodies.

Thiopurine-mediated impairment of hematopoietic stem and leukemia cells in Nudt15R138C knock-in mice

Thiopurines are widely used as antileukemia agents and immunosuppressants. Recent large-scale clinical studies revealed a strong association between the NUDT15 p.Arg139Cys (NUDT15^R139C) polymorphism and severe thiopurine-induced leukocytopenia. We established knock-in mice harboring p.Arg138Cys (Nudt15^R138C), which corresponds to the human polymorphism. A clinically relevant dose of mercaptopurine (MP) induced lethal cytopenia in Nudt15^R138C-harboring mice. MP dose reduction attenuated the hematopoietic toxicity, phenocopying clinical observations and providing Nudt15 genotype-based tolerable doses of MP. High-dose MP induced acute damage to hematopoietic stem and progenitor cells (HSPCs) in Nudt15^R138C/R138C mice. A competitive transplantation assay revealed that not only Nudt15^R138C/R138C HSPCs, but also Nudt15^+/R138C HSPCs suffered stronger damage than Nudt15^+/+ HSPCs, even by lower-dose MP, after long-term administration. In a Nudt15 genotype-based posttransplantation leukemia recurrence model generated by bone marrow replacement with congenic wild-type cells and a small number of leukemia stem cells, MP prolonged the survival of mice with posttransplantation Nudt15^R138C/R138C leukemia recurrence. In conclusion, our model will facilitate NUDT15 genotype-based precision medicine by providing safer estimates for MP dosing, and our findings highlighted the high susceptibility of hematopoietic stem cells to MP and suggested that exploiting thiopurine toxicity might be a novel treatment approach for leukemia in NUDT15^R139C-harboring patients.

Predictors of return to work after kidney transplantation: a 12-month cohort of the Japan Academic Consortium of Kidney Transplantation study

OBJECTIVES

To investigate the cumulative return-to-work (RTW) rate and to identify predictors of employment after kidney transplantation (KT).

DESIGN

Retrospective, outpatient-based cohort study.

SETTING

This was a single-centre study of the largest Japanese kidney transplant centre.

PARTICIPANTS

We selected Japanese kidney transplant recipients aged 20-64 years who were employed in paid jobs at the time of transplantation and who visited an outpatient clinic from December 2017 to March 2018. From 797 patients, we evaluated 515 in this study.

INTERVENTIONS

We interviewed patients at an outpatient clinic and investigated the timing and predictors of RTW using logistic regression models.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the cumulative RTW rate, and the secondary outcome was to investigate the predictors of RTW after KT.

RESULTS

Among the 515 included recipients, the cumulative overall partial/full RTW rates at 2, 4, 6 and 12 months were 22.3%, 59.0%, 77.1% and 85.0%, respectively. The median duration from transplantation to RTW was 4 months. Regarding partial/full RTW, according to the multivariable analysis including all variables, male sex was a greater predictor for RTW than female sex (OR 2.05, 95% CI 1.32 to 3.20), and a managerial position was a greater predictor than a non-managerial position (OR 2.23, 95% CI 1.42 to 3.52). Regarding full RTW, male sex (OR 1.95, 95% CI 1.25 to 3.06) and managerial position (OR 1.95, 95% CI 1.25 to 3.06) were also good predictors.

CONCLUSIONS

The cumulative RTW rate was 85.0% 1-year post-transplantation. Given that cumulative RTW rates varied by sex and position, transplant and occupational physicians should support kidney transplant recipients in the aspect of returning to work.

TRIAL REGISTRATION NUMBER

UMIN000033449.

Association between response to rituximab and antibody-mediated rejection in ABO-incompatible living kidney transplantation

OBJECTIVES

To examine the association of response to rituximab and the incidence of antibody-mediated rejection in preconditioning of rituximab and plasma exchange without post-transplant plasmapheresis in patients undergoing ABO-incompatible living kidney transplantation.

METHODS

A total of 115 patients who underwent ABO-incompatible living kidney transplantation at Tokyo Women's Medical University Hospital, Tokyo, Japan, were divided into two groups based on the response to rituximab: good response (n = 75) or poor response (n = 40). The rituximab good response and poor response patients were defined as patients whose CD19⁺ cells were non-detected (0%) and detected on the day of transplantation (2-5 days, median 3 days, after rituximab administration), respectively.

RESULTS

Rituximab response and anti-A/B blood antibody titer after plasmapheresis were significant risk factors for antibody-mediated rejection (P = 0.036, 0.045, respectively). The occurrence of antibody-mediated rejection was higher in the poor response group than in the good response group (22.5% vs 8.0%; P = 0.028). The 14-day, 3-month and 1-year cumulative incidence of antibody-mediated rejection was 2.7%, 5.3% and 8.0% in the good response group, and 17.5%, 20.0% and 22.5% in the poor response group after ABO-incompatible living kidney transplantation. The patient survival was not significantly different between the two groups. However, graft survival 1 month after transplantation was lower in the poor response group. There is no significant difference in graft function and in the incidence of complications, including infection, after transplantation between the two groups.

CONCLUSIONS

Antibody-mediated rejection after ABO-incompatible living kidney transplantation was significantly associated with the response to rituximab in our preconditioning protocol.