HIV/AIDS knowledge level, awareness of public health centers and related factors: a cross-sectional study among Brazilians in Japan.

BACKGROUND: Accurate information is essential so that HIV infection can be detected in time for initiation of HIV/AIDS treatment. Immigrants are at high risk for delayed HIV testing and diagnosis, but foreign residents in Japan also seem to face barriers to accessing HIV/AIDS care. We aimed to assess their knowledge level of HIV/AIDS and awareness of public health centers in Japan (PHCs), and to explore factors related to these items. METHODS: We conducted a cross-sectional study of Brazilians, the largest group of foreigners living in Shiga, using an anonymous, self-administered questionnaire survey in Brazilian Portuguese and Japanese via the Internet and mail. A multiple logistic regression analysis was used to examine the factors related to "Knowledge of HIV/AIDS" and "Awareness of PHCs". RESULTS: A total 182 Brazilians responded. More than half of them were beginners in Japanese. Most respondents were familiar with HIV/AIDS, but only 58% knew the existence of PHCs, and only 25% knew that HIV testing is available at PHCs free of charge and anonymously. A multiple logistic regression analysis showed that PHCs were less recognized by those with intermediate (odds ratio: 5.70, 95% confidence interval: 1.53-21.23) and beginner (odds ratio: 6.81, 95% confidence interval: 1.98-23.45) Japanese proficiency than by those with advanced. CONCLUSIONS: This survey revealed the knowledge level of HIV/AIDS and awareness of PHC among Brazilians in Shiga. Their lack of awareness of PHCs due to language barriers may lead to delays in HIV testing among them. Therefore, it is important for PHCs to disseminate information about medical services related to HIV/AIDS in Portuguese and plain Japanese to facilitate their access to HIV testing. However, PHC efforts alone are not enough. Medical interpreters who are familiar with Brazilian culture and customs, and the clinics that employ them, could help the Brazilian community and PHCs to overcome the language barrier and provide efficient and appropriate medical care to Brazilians. This would be one way to eliminate delays in HIV testing for Brazilians in Shiga.

Diagnostic utility of programmed cell death ligand 1 (clone SP142) in mediastinal composite lymphoma: A report of two cases.

Composite lymphoma is a well-known diagnostic entity exhibiting the synchronous occurrence of two or more distinct types of lymphomas in the same specimen. Here we report two patients, a 14-year-old female (Case 1) and a 45-year-old male (Case 2), with mediastinal composite lymphoma, comprising nodular sclerosis classic Hodgkin lymphoma (NSCHL) and primary mediastinal large B-cell lymphoma (PMBL). Both patients had a mediastinal mass, and manifested two different histologic components in the same biopsy, one characteristic of NSCHL and the other PMBL. The NSCHL areas included Hodgkin and Reed-Sternberg (HRS) cells with typical immunophenotypic features (CD30-positive and CD20-negative), whereas the sheets of large tumor cells characteristic of PMBL were strongly and uniformly CD20-positive. Interestingly, although both cases showed neoplastic PD-L1 (nPD-L1) positivity on the HRS cells of NSCHL, they differed regarding nPD-L1 expression on the PMBL tumor cells. In Case 1, the nPD-L1-negative PMBL component was anatomically situated outside the NSCHL lesion. On the other hand, in Case 2, the nPD-L1-positive PMBL component was characterized by transitional or continuous areas with the NSCHL component. These findings suggested that nPD-L1 expression may define two subtypes of PMBL that are more similar to or distinct from classic Hodgkin lymphoma.

[Immunohistochemical evaluation of BCL-2 expression in acute myeloid leukemia, myeloid sarcoma, and blastic plasmacytoid dendritic cell neoplasm].

Venetoclax, a selective BCL-2 inhibitor, is prescribed clinically for acute myeloid leukemia (AML) treatment. However, it is unclear if known chromosomal or genetic abnormalities associated with AML also influence BCL-2 expression. Few studies have examined BCL-2 expression in AML-related precursor neoplasms such as primary myeloid sarcoma (MS) and blastic plasmacytoid dendritic cell neoplasm (BPDCN). In this study, we examined BCL-2 expression using immunohistochemistry in 7 patients with AML, who also carried genetic and chromosomal abnormalities typical to AML including t (8;21), t (15;17), FLT3-ITD mutation, and complex karyotype, along with 1 patient with primary MS and 3 patients with BPDCN. As a result, expression of BCL-2 was observed in all patients with AML and 1 patient with primary MS. In the patients with BPDCN, BCL-2 was highly expressed in all regions with evidence of tumor cell infiltration, such as skin, bone marrow, and lymph node. These results could be used as evidence in the support of administering venetoclax to adverse-risk patients with AML, MS, or BPDCN.

[Significance of monitoring cerebrospinal fluid leukocyte counts in managing central nervous system disease of acute myeloid leukemia in patients presenting with intracerebral hemorrhage upon initial examination].

A 17-year-old woman was urgently transported to our hospital due to consciousness disturbance. A blood examination revealed intracerebral hemorrhage, WBC 233,800/l, blasts 93%, and disseminated intravascular coagulation. The results of bone-marrow aspiration indicated acute myeloid leukemia (M2 in FAB classification) with t (7;11) (p15;p15) and the resulting chimeric gene NUP98-HOXA9 and with FLT3-ITD. Following hematoma evacuation, induction therapy was initiated and the leukocytes in the cerebrospinal fluid observed in the spinal drainage were monitored. Because they increased on days 5 and 9 after the completion of induction therapy, intrathecal chemotherapy (IT) was performed; this finally contributed to controlling AML in the central nervous system (CNS), together with the restoration of normal hematopoiesis. Subsequently, after complete molecular remission with consolidation therapies containing high-dose cytarabine, a bone-marrow transplantation with a myeloablative regimen was conducted from a 1-allele mismatched sibling donor. Finally, the patient was discharged without major sequela on day 228 after the first visit. The management of CNS disease in AML with intracerebral hemorrhage remains unclear. Our case suggests that IT at the appropriate time based on the monitored number of cerebrospinal fluid leukocytes could be useful in controlling AML in the CNS after intracerebral hemorrhage.

Plasma presepsin level is an early diagnostic marker of severe febrile neutropenia in hematologic malignancy patients.

BACKGROUND: Febrile neutropenia (FN) is a common infectious complication in chemotherapy. The mortality of FN is higher in hematologic malignancy patients, and early diagnostic marker is needed. Presepsin is a prompt and specific marker for bacterial sepsis, but its efficacy in severe febrile neutropenia (FN) is not well confirmed. We tried to clarify whether it is a useful maker for early diagnosis of FN in patients during massive chemotherapy. METHODS: We measured plasma presepsin levels every 2-3 day in FN cases and evaluated its change during the course of massive chemotherapy. The patients had hematologic malignancy or bone marrow failure, and in all cases, neutropenia was severe during the episode. The baseline levels, onset levels, increase rate at FN onset, and onset / baseline ratio were evaluated for their efficacy of early FN diagnosis. RESULTS: Eleven episodes of bacteremia (six gram negatives and five gram positives) in severe neutropenia were analyzed in detail. While plasma presepsin level was strongly associated to the CRP level (r = 0.61, p < 0.01), it was not associated with the absolute WBC count (r = -0.19, p = 0.19), absolute neutrophil count (r = -0.11, p = 0.41) or absolute monocyte count (r = -0.12, p = 0.40). The average of onset presepsin level was 638 ± 437 pg/mL and the cutoff value (314 pg/mL) has detected FN onset in 9 of 11 cases. The two cases undetected by presepsin were both Bacillus species bacteremia. CONCLUSIONS: Plasma presepsin level is a reliable marker of FN even in massive chemotherapy with very low white blood cell counts. Closer monitoring of this molecule could be a help for early diagnosis in FN. But bacteremia caused by Bacillus species was an exception in our study.

Comparison of the gut microbial community between obese and lean peoples using 16S gene sequencing in a Japanese population.

Altered gut microbial ecology contributes to the development of metabolic diseases including obesity. In this study, we performed 16S rRNA sequence analysis of the gut microbiota profiles of obese and lean Japanese populations. The V3-V4 hypervariable regions of 16S rRNA of fecal samples from 10 obese and 10 lean volunteers were sequenced using the Illumina MiSeq(TM)II system. The average body mass index of the obese and lean group were 38.1 and 16.6 kg/m(2), respectively (p<0.01). The Shannon diversity index was significantly higher in the lean group than in the obese group (p<0.01). The phyla Firmicutes and Fusobacteria were significantly more abundant in obese people than in lean people. The abundance of the phylum Bacteroidetes and the Bacteroidetes/Firmicutes ratio were not different between the obese and lean groups. The genera Alistipes, Anaerococcus, Corpococcus, Fusobacterium and Parvimonas increased significantly in obese people, and the genera Bacteroides, Desulfovibrio, Faecalibacterium, Lachnoanaerobaculum and Olsenella increased significantly in lean people. Bacteria species possessing anti-inflammatory properties, such as Faecalibacterium prausnitzii, increased significantly in lean people, but bacteria species possessing pro-inflammatory properties increased in obese people. Obesity-associated gut microbiota in the Japanese population was different from that in Western people.

FUS-ERG induces late-onset azacitidine resistance in acute myeloid leukaemia cells.

FUS-ERG is a chimeric gene with a poor prognosis, found in myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). It remains unclear whether DNA hypomethylating agents, including azacitidine (Aza), are effective in FUS-ERG-harbouring AML and how FUS-ERG induces chemoresistance. Stable Ba/F3 transfectants with FUS-ERG were repeatedly exposed to Aza for 7 days of treatment and at 21-day intervals to investigate Aza sensitivity. Stable FUS-ERG transfectants acquired resistance acquired resistance after three courses of Aza exposure. RNA sequencing (RNA-seq) was performed when Aza susceptibility began to change; genes with altered expression or transcript variants were identified. Molecular signatures of these genes were analysed using gene ontology. RNA-seq analyses identified 74 upregulated and 320 downregulated genes involved in cell motility, cytokine production, and kinase activity. Additionally, 1321 genes with altered transcript variants were identified, revealing their involvement in chromatin organisation. In a clinical case of AML with FUS-ERG, we compared whole-genome alterations between the initial MDS diagnosis and AML recurrence after Aza treatment. Genes with non-synonymous or near mutations in transcription regulatory areas (TRAs), additionally detected in AML recurrence, were collated with the gene list from RNA-seq to identify genes involved in acquiring Aza resistance in the presence of FUS-ERG. Whole-genome sequencing of clinical specimens identified 29 genes with non-synonymous mutations, including BCOR, and 48 genes located within 20 kb of 54 TRA mutations in AML recurrence. These genes were involved in chromatin organisation and included NCOR2 as an overlapping gene with RNA-seq data. Transcription regulators involved in mutated TRAs were skewed and included RCOR1 in AML recurrence. We tested the efficacy of BH3 mimetics, including venetoclax and S63845, in primary Aza-resistant AML cells treated with FUS-ERG. Primary FUS-ERG-harbouring AML cells acquiring Aza resistance affected the myeloid cell leukaemia-1 (MCL1) inhibitor S63845 but not while using venetoclax, despite no mutations in BCL2. FUS-ERG promoted Aza resistance after several treatments. The disturbance of chromatin organisation might induce this by co-repressors, including BCOR, NCOR2, and RCOR1. MCL1 inhibition could partially overcome Aza resistance in FUS-ERG-harbouring AML cells.

Rare monomorphic epithelial intestinal T-cell lymphoma of the stomach with a giant gastric perforation rescued by liver-covering sutures followed by a total gastrectomy and lateral hepatectomy: a case report.

BACKGROUND: Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), a type of peripheral T-cell lymphoma, rarely involves the stomach as the primary organ. Advanced MEITL, for which there is currently no established treatment, causes gastrointestinal perforations and is characterized by a poor response to chemotherapy. CASE PRESENTATION: A 69-year-old man had undergone chemotherapy for MEITL of the whole stomach. He subsequently developed acute abdominal pain, and computed tomography revealed a giant perforation in the anterior gastric wall adjacent to the lateral segment of the liver. The perforation was rescued through closure with liver-covering sutures. Thereafter, a total gastrectomy and a left hepatectomy were performed and he recovered enough to tolerate oral intake. However, despite ongoing chemotherapy, the patient died 83 days after the gastric perforation (10 months after being diagnosed with the lymphoma) owing to rapid progression of the MEITL. CONCLUSION: In the rare case of a giant gastric perforation after chemotherapy for gastric MEITL, rescue is possible through liver-covering sutures followed by a total gastrectomy and lateral hepatectomy.

Acquired Coagulation Factor V Inhibitor That Was Successfully Treated with Oral Corticosteroid Therapy.

Acquired coagulation factor V (FV) inhibitors are rare disorders in which antibodies against FV develop under various conditions. We herein report the case of a 71-year-old woman with FV inhibitor during radiochemotherapy for pancreatic cancer. Multiple purpuras suddenly appeared on her bilateral upper limbs with prolonged coagulation data (APTT 97.3 seconds). The FV activity was less than 3% and the FV inhibitor was positive (1.7 B.U./mL). Oral prednisolone induced a rapid normalization of the coagulation data and FV activity and a rapid disappearance of FV inhibitor within 7 days. Early diagnosis and treatment may therefore be important in cases of FV inhibitor.

A case of life-threatening small intestinal bleeding accompanied by lower coagulation factor XIII activity.

We report a case of life-threatening bleeding from the small intestine accompanied by lower coagulation factor XIII (FXIII) activity. A 43-year-old man was admitted because of continuous small intestinal bleeding. He had no family or past history of bleeding. He received high volume transfusion of red blood cells (total 20 unit) for persistent bleeding. All routine coagulation tests were normal, and plasma FXIII activity was 41%. Cross-mixing studies suggested an absence of autoantibodies to FXIII. Contrast-enhanced computed tomography and repeated balloon-assisted enteroscopy could not detect the focus of bleeding. The administration of purified concentrate of FXIII immediately halted the bleeding from the small intestine. Since then, he experienced no bleeding episode and has been maintaining normal FXIII activity.

LSD1-mediated repression of GFI1 super-enhancer plays an essential role in erythroleukemia.

Super-enhancers (SEs) consist of enhancer clusters with abundant binding of transcription factors (TFs) and cofactors. LSD1 is a histone modifier that eliminates SE activity. However, whether SE suppression by LSD1 is associated with leukemogenesis remains unknown. In erythro-megakaryocyte lineage leukemia cells, activation of the SE of GFI1 (GFI1-SE) is related to induction of myeloid differentiation by LSD1 inhibitors NCD38 and NCD25 and to their antileukemia effect. Although functional TF-motifs were concentrated in an evolutionally conserved area, NCD38 barely induced additional TF recruitment. Instead, the transcription cofactors including LSD1, CoREST, HDAC1, and HDAC2 were evicted from GFI1-SE. Deletion of GFI1-SE impaired induction of myeloid differentiation by NCD38 and NCD25 in erythroleukemia cells. Gene set enrichment analysis revealed that the GFI1-SE deletion impaired NCD38-induced programs related to granulocyte differentiation and the CEBPA network, but restored NCD38-suppressed programs related to erythroid development, GATA1 targets, and acute myeloid leukemia (AML) clusters including FAB subtype M6 and AML with myelodysplastic syndrome-related chromosomal abnormalities. Ontologies of genes whose expression changes by NCD38 were canceled due to the GFI1-SE deletion showed enrichment in AML and neutropenia signatures. Collectively, our data suggest that sustainable repression of GFI1-SE by LSD1 is essential for sustenance of erythroleukemia cells.

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 (NUDT15R139C) polymorphism and severe thiopurine-induced leukocytopenia. We established knock-in mice harboring p.Arg138Cys (Nudt15R138C), which corresponds to the human polymorphism. A clinically relevant dose of mercaptopurine (MP) induced lethal cytopenia in Nudt15R138C-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 Nudt15R138C/R138C mice. A competitive transplantation assay revealed that not only Nudt15R138C/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 Nudt15R138C/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 NUDT15R139C-harboring patients.

Lipoid pneumonia with chronic myelomonocytic leukemia.

A case of lipoid pneumonia with chronic myelomonocytic leukemia is reported. A 61-year-old man was autopsied after suffering from myelodysplastic syndrome (chronic myelomonocytic leukemia) for 13 years. Interstitial lesions of the lungs were suspected as infiltration of leukemia cells before the autopsy. However, blastic leukemia cells were not observed in the lung, although they were seen in the bone marrow and spleen at autopsy. Instead, an unusual amount of cholesterol deposits was observed with mucormycosis and aspergillosis in the lungs. Cholesterol deposition was observed not only in perihilar but also in subpleural regions without apparent bronchial obstruction in both lungs. It is thought that malfunction of monocytes/macrophages resulted in repeated fungal infection and storage of cholesterol caused by tissue destruction and impaired tissue repairing.

Granisetron plus aprepitant versus granisetron in preventing nausea and vomiting during CHOP or R-CHOP regimen in malignant lymphoma: a retrospective study.

BACKGROUND: Cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) regimen includes a high dose of prednisolone (100 mg/body), which exhibits an anticancer and antiemetic effect. However, its optimal use for antiemetic therapy has not been established yet. We assessed the efficacy of granisetron plus aprepitant versus granisetron for CHOP or rituximab-CHOP (R-CHOP) regimen-induced nausea and vomiting in malignant lymphoma. METHODS: This retrospective and observational clinical study included patients who received CHOP or R-CHOP regimen as initiating chemotherapy between July 2010 and March 2016 (N = 39). Patients were assigned to an aprepitant [aprepitant (125 mg on day 1, 80 mg on days 2-3) plus granisetron (3 mg); n = 15] or control regimen group [granisetron (3 mg); n = 24]. Complete response (CR), defined as no vomiting and no use of rescue therapy during overall phase (0-120 h), was the primary endpoint. Secondary endpoints included the time to first vomiting and using rescue medication and complete protection (CP) defined as no vomiting and no retching and/or no nausea and no rescue therapy. The patient records were investigated, and data were retrospectively analyzed. RESULTS: CR rate CP rates did not significantly differ between the groups during the observation period (80.0% versus 83.3%, p = 1.000; and 80.0% versus 79.2%, p = 1.000, respectively). Additionally, the time to first vomiting and using rescue medication in did not significantly differ between the groups (p = 0.909). CONCLUSIONS: This study suggests that granisetron alone could be one treatment option in the management of CINV in patients with non-Hodgkin lymphoma receiving CHOP or R-CHOP regimen.

Severe Colitis with Portal Venous Gas Caused by Brachyspira pilosicoli Infection.

We herein report a case of Brachyspira pilosicoli-caused severe colitis presenting with portal venous gas. A 75-year-old man was admitted because of a fever, severe abdominal pain and bloody diarrhea. He was negative for anti-HIV antibodies. He had been in close contact with a dog earlier. Abdominal computed tomography detected severe wall-thickening and fat-stranding of the entire colon accompanied by portal venous gas. A smear examination of his stool showed many Gram-negative spiral rods, suggesting intestinal spirochetosis. A polymerase chain reaction assay using stool samples detected an amplified band specific for B. pilosicoli. He responded well to antimicrobial agents including metronidazole.

A novel mutation causing type 1 Gaucher disease found in a Japanese patient with gastric cancer: A case report.

RATIONALE: Gaucher disease (GD) is an autosomal recessive disorder that leads to multiorgan complications caused by ß-glucocerebrosidase deficiency due to mutations in the ß-glucocerebrosidase-encoding gene (GBA). GD morbidity in Japan is quite rare and clinical phenotype and gene mutation patterns of patients with GD in Japan and Western countries differ considerably. Of Japanese patients with GD, 57% develop types 2 or 3 GD with neurologic manifestations and younger onset, whereas only 6% of patients with GD develop those manifestations in Western countries. Thus, it is relatively difficult to find and diagnose GD in Japan. PATIENT CONCERNS: A 69-year-old Japanese female with mild anemia and thrombocytopenia but without neurologic symptoms was initially referred for gastric cancer. Preoperative F-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) showed accumulation in the bone marrow and paraabdominal lymph nodes. Following bone marrow aspiration found, abnormal foamy macrophages in the bone marrow and electron microscopy revealed that the macrophages were filled with tubular-form structures. Adding to these signs suggestive of a lysosomal disease, serum ß-glucocerebrosidase activity test found decreased. Sequencing of the patient's GBA gene revealed a RecNciI recombinant mutation and the novel mutation K157R (c.587A>G). DIAGNOSES: On the basis of these findings and clinical manifestations, the final diagnosis of type 1 GD was made. INTERVENTIONS: Enzyme replacement therapy (ERT) with velaglucerase α was started after the diagnosis of type 1 GD. OUTCOMES: The patient's ß-glucocerebrosidase activity as well as hemoglobin and platelet levels were restored by ERT without any side effects. Bone marrow aspirations 10 months after the start of the treatment with velaglucerase α showed reduction of Gaucher cells in bone marrow to 2% from 4% of total cellularity. LESSONS: This is the first report of F-FDG PET/CT application providing a clue for GD diagnosis. A novel mutation in GBA is described, which implies a potential pool of patients with GD with this mutation in Japan.

Wilms tumor gene WT1 peptide-based immunotherapy induced a minimal response in a patient with advanced therapy-resistant multiple myeloma.

The product of the Wilms tumor gene, WT1, is a universal tumor antigen. We performed WT1 peptide-based immunotherapy for a patient with multiple myeloma (MM). This patient was a 57-year-old woman with chemotherapy-resistant MM (Bence Jones kappa type). The patient received weekly intradermal injections of an HLA-A*2402-restricted 9-mer WT1 peptide emulsified with Montanide ISA 51 adjuvant for 12 weeks and achieved a minimal response according to European Group for Blood and Marrow Transplantation criteria without experiencing systemic adverse effects. The proportion of myeloma cells in the bone marrow (BM) decreased from 85% to 25%, and the amount of M protein in the urine decreased from 3.6 to 0.6 g/day after WT1 vaccination. Furthermore, a bone scintigram showed an improvement after the vaccination. As for immunologic parameters, the frequency of WT1 tetramer-positive cells among CD8+ T-cells, which was higher than in healthy donors, temporarily decreased at weeks 4 and 8 but increased at week 12, whereas the frequency of WT1 peptide-responding CD107a/b+ cells among WT1 tetramer-positive T-cells increased from 27.0% to 38.6% after the vaccination. After WT1 vaccination, the frequency of CXCR4+ cells among WT1 tetramer-positive T-cells increased in the BM, where stromal cells expressed the ligand for CXCR4, stromal-derived factor 1 (SDF-1), but decreased in the peripheral blood (PB), implying that WT1-specific cytotoxic T-lymphocytes had migrated from the PB to the BM, a tumor site.

Central nervous system involvement of acute promyelocytic leukemia, three case reports.

Central nervous system (CNS) involvement of acute promyelocytic leukemia (APL) causes poor prognosis. Our three cases show that CNS can be involved at the first hematological recurrence, but predicting this is difficult. Triple intrathecal treatment and craniospinal irradiation were effective, while arsenic oxide failed to prevent and improve CNS involvement.

NUDT15 R139C-related thiopurine leukocytopenia is mediated by 6-thioguanine nucleotide-independent mechanism in Japanese patients with inflammatory bowel disease.

BACKGROUND: NUDT15 R139C (rs116855232) is a recently identified genetic factor responsible for thiopurine-induced leukocytopenia and hair loss. In this study, we investigated the association of NUDT15 R139C with 6-thioguanine nucleotide (6-TGN) levels and thiopurine-induced leukocytopenia in Japanese patients with inflammatory bowel disease (IBD). METHODS: Two hundred and sixty-four subjects (103 healthy volunteers and 161 IBD patients treated with thiopurines) were enrolled. Genotyping for NUDT15 R139C was performed using Custom TaqMan® SNP genotyping assays. RESULTS: The NUDT15 C/C, C/T, and T/T genotypes were 80.7, 18.2, and 1.1 %, respectively. The allelic frequency was 10.2 %. Among 161 IBD patients, there was no significant difference in 6-TGN levels among the NUDT15 genotypes. Forty-five patients (27.9 %) developed leukocytopenia (WBC <3000/µl), and the C/T and T/T genotypes were significantly associated with the development of leukocytopenia (P = 1.7 × 10(-5)). In these patients, 6-TGN levels were not significantly different between NUDT15 genotypes. NUDT15 R139C was significantly associated with early (<8 weeks) (P = 1.03 × 10(-4)) and late (>8 weeks) leukocytopenia (P = 4.3 × 10(-4)). The decrease in WBC count at 2 and 4 weeks was significantly higher in patients with the C/T or T/T genotypes as compared to the patients with the C/C genotype. All patients with the T/T genotype (n = 2) developed early severe hair loss and severe leukocytopenia (<1000/µl). The logistic regression analysis revealed that NUDT15 R139C was the sole genetic factor responsible for the thiopurine-induced leukocytopenia (P = 0.001). CONCLUSIONS: These results suggest that NUDT15 R139C-related thiopurine-induced leukocytopenia is mediated by a 6-TGN-independent mechanism.