Genetic polymorphisms and their association with methotrexate polyglutamates during maintenance treatment in Korean children and young adults with acute lymphoblastic leukemia.

The aim of this study was to investigate the impact of genetic polymorphisms on methotrexate (MTX) metabolism in Korean children and young adults with acute lymphoblastic leukemia, specifically focusing on MTX polyglutamates (MTX-PGs) in erythrocytes, which have been rarely studied. Korean children and young adult patients undergoing maintenance therapy for acute lymphoblastic leukemia, who were receiving weekly oral MTX doses of 20 mg/m²/week, were prospectively included. We investigated erythrocyte MTX-PG (PG1 to PG5) levels, MTX-PG/MTX dose ratios, and 222 genetic polymorphisms spanning 78 genes and three intergenic areas related to MTX transport, folate cycle metabolism, purine/pyrimidine pathways, and non-pathway genes (including TPMT and NUDT15 genotypes) to explore their association with MTX metabolism. MTX-PG levels were associated with MTX dose (p < 0.05), and MTX-PG3 comprised the majority of the total MTX-PGs, with a median of 39.3 %. Various polymorphisms within the same gene demonstrated differing associations with each type of MTX-PG, underscoring the complexity of MTX pharmacogenetics. Among the polymorphisms examined, 14 across 13 genes showed significant associations with MTX-PG2-5 levels, even after adjusting for the false discovery rate (ABCC5, ATG16L1, CEP72, FSTL5, GMPS, HTR3A, IMPDH1, NT5C2, SLC28A3, SLCO1B3, SUCLA2, TPMT, and TYMS). This study enhances our understanding of genetic polymorphisms in MTX metabolism and therapeutic monitoring for MTX maintenance, promoting personalized medicine in acute lymphoblastic leukemia patients.

Comparative Analysis of Seven Equations for Estimated Glomerular Filtration Rate and Their Impact on Chronic Kidney Disease Categorization in Korean Patients at Local Clinics and Hospitals.

(1) Background: Accurate estimation of the glomerular filtration rate (eGFR) is essential for the early detection of chronic kidney disease (CKD), targeted interventions, and ongoing monitoring. Although various equations for calculating eGFR exist, comparative studies on eGFR levels and the impact of these equations on CKD prevalence are limited in the Korean population. (2) Methods: We compared eGFR levels calculated using seven equations and investigated the prevalence of CKD through a retrospective analysis of the data from Korean adult patients who visited local clinics and hospitals and underwent simultaneous serum creatinine (Cr) and cystatin C (Cys-C) measurements. The equations analyzed were: 2006 MDRD, 2009 CKD-EPI Cr, 2012 CKD-EPI Cys-C, 2012 CKD-EPI Cr & Cys-C, 2021 CKD-EPI Cr, 2021 CKD-EPI Cr & Cys-C, and 2021 EKFC. (3) Results: This study included 6688 Korean patients (3736 men and 2952 women; median age: 61.4; IQR: 47.2-73.4). Among the equations, the median eGFR levels were the highest when using the 2021 CKD-EPI Cr & Cys-C equation (85.1 mL/min/1.73 m2) and the lowest when using the 2006 MDRD equation (73.4 mL/min/1.73 m2). The highest prevalence of decreased eGFR < 60 mL/min/1.73 m2 (equivalent to or worse than G3a CKD) was noted with the 2012 CKD-EPI Cys-C equation (32.4%), while the lowest was with the 2021 CKD-EPI Cr equation (22.9%), resulting in a maximum prevalence difference of 9.5%. (4) Conclusions: The prevalence of CKD varies based on the eGFR equation used and the patient's age. Equations that include Cys-C may identify a larger number of patients with decreased kidney function.

Prevalence of Iron Deficiency Anemia Indicated for Intravenous Iron Treatment in the Korean Population.

We aimed to investigate the number and prevalence of patients indicated for intravenous iron treatment in a large Korean population using criteria based on laboratory test results in an effort to extract indirect information on the need for intravenous iron treatment. Between 1 January 2019 and 31 December 2021, a total of 83,994 Korean patients (30,499 men and 53,495 women) with a median age of 46 years (interquartile range, 30-61) were evaluated using iron deficiency anemia-associated laboratory tests and serum creatinine tests of estimated glomerular filtration rates. The overall prevalence of anemia (Hb ≤ 11 g/dL) was 16.5%, and the proportion of patients with possible chronic kidney disease who had an estimated glomerular filtration rate < 60 mL/min/1.73 m2 was 11.4%. The number of patients indicated for reimbursable intravenous iron treatment was higher in women than in men, higher in older patients, and higher in 2021 than in 2019 (all p < 0.001). The prevalence of patients indicated for reimbursable intravenous iron treatment was up to 30.0% in those ≥ 80 years of age in 2019. The results of this study provide basic knowledge about the use of iron deficiency anemia-associated laboratory tests in planning nutritional support programs using an intravenous iron formulation in Korea.

Seroprevalence of Anti-Thyroglobulin Antibodies in Korea.

BACKGROUND: The appropriate use of the thyroglobulin (Tg) test involves the concurrent measurement of Tg auto-antibodies (Tg Ab) due to the potential for false low or false high Tg due to Tg Ab interference. METHODS: We retrospectively reviewed Tg and Tg Ab test results requested from local clinics and hospitals in Korea between July 1, 2020 and June 30, 2021. RESULTS: During the study period, 13,811 Tg tests were performed. Among them, 6,769 Tg tests were identified as being repeatedly measured from 2,988 Korean adults. Among the 6,769 performed Tg tests, 2,733 (40.4%) did not have concurrently performed Tg Ab tests. Among the 2,988 subjects, 1,089 (36.4%) had no concurrently measured Tg Ab test results. Among 4,036 Tg results with concurrently measured Tg Ab, 1,045 (25.9%) had positive Tg Ab results, which could interfere with Tg concentration measurements. CONCLUSIONS: The Tg Ab test appears to be underutilized in Korea.

Reference intervals of anti-Müllerian hormone in Korean women.

BACKGROUND: Limited data are available with reference intervals of serum anti-Müllerian hormone (AMH) level in Korean women. METHODS: We retrospectively reviewed serum AMH test results performed with automated electrochemiluminescence immunoassay in Korean women who visited health promotion centers between January 2019 and December 2020. Serum AMH results by age group were compared with previously reported reference intervals. RESULTS: During the 2-year study period, a total of 1953 AMH test results from Korean women (age 20-49 years) undergoing general health checkups were obtained. Serum AMH level differed significantly by age group. Peak AMH level was observed at age 25-29 years and decreased to undetectable for subjects older than 44 years. The 2.5th, 5th, and 10th percentile values of the present study were comparable with previously assessed lower limits of reference intervals. The upper limit of the reference interval defined as the 97.5th percentile value in women younger than 35 years was higher than that of Western populations. The 90th percentile value of the present study population was similar to the 95th or 97.5th percentile value of reference intervals for Western populations of women younger than 35 years. CONCLUSION: Understanding patient populations and differences in reference intervals by age group and measurement method can help guide clinical decisions and clinical laboratory analysis.

Intraindividual Changes in Mac-2 Binding Protein Glycosylation Isomer (M2BPGi) Performed in Korean Subjects.

BACKGROUND: Limited data are available regarding intraindividual changes in the Mac-2 binding protein glycosylation isomer (M2BPGi), a liver fibrosis biomarker, performed for health checkups in Korean subjects. METHODS: Through a laboratory information system, we retrospectively investigated longitudinally measured M2BPGi to assess intraindividual changes in M2BPGi test results. RESULTS: During a 38-month study period, 526 test results from 246 Korean subjects undergoing general health checkups were requested from 13 local clinics and hospitals. Among all 246 subjects, 190 (77.2%) exhibited negative M2BPGi (< 1.0 C.O.I.) during the initial measurement. Among all 246 subjects, 210 (85.4%) did not experience any changes in qualitative results during a follow-up. Among 42 subjects with initially 1+ positive results for M2BPGi, 17 (40.5%) changed to a negative M2BPGi result at least once during follow-up. No subjects with initially negative results or 1+ positive (1.0 ≤ C.O.I. < 3.0) results changed to 2+ positive (≥ 3.0 C.O.I.) results during the 38-month follow-up period. CONCLUSIONS: Some subjects exhibited qualitative changes in M2BPGi during follow-up health examinations. Future studies are needed to clarify the clinical implication of such changes.

Prenatal diagnosis of combined methylmalonic acidemia and homocystinuria cobalamin C type using clinical exome sequencing and targeted gene analysis.

BACKGROUND: Combined methylmalonic acidemia and homocystinuria is a rare inherited disorder of intracellular cobalamin metabolism caused by biallelic variants in one of the following genes: MMACHC (cblC), MMADHC (cblD), LMBRD1 (cblF), ABCD4 (cblJ), THAP11 (cblX-like), and ZNF143 (cblX-like), or a hemizygous variant in HCFC1 (cblX). Prenatal diagnosis of combined methylmalonic acidemia with homocystinuria is crucial for high-risk couples since the disorder can be life-threatening for offspring. We would like to describe two infant deaths both of which are likely attributable to cblC despite not having a genetic confirmation, and subsequent pregnancy and prenatal genetic testing. METHODS: Parental clinical exome sequencing and targeted Sanger sequencing of MMACHC gene in amniotic fluid was performed to check the carrier status of the fetus. RESULTS: Parental clinical exome sequencing revealed a heterozygous pathogenic variant [NM_015506.2:c.217C>T (p.Arg73*)] in the MMACHC gene of the mother and [NM_015506.2:c.609G>A (p.Trp203*)] in the MMACHC gene of the father. Targeted Sanger sequencing of MMACHC gene in amniotic fluid revealed that the fetus carried only one nonsense variant [NM_015506.2:c.609G>A (p.Trp203*)], which was inherited from the father. The mother delivered a healthy baby and the neonate did not show any symptoms or signs of combined methylmalonic acidemia and homocystinuria after birth. CONCLUSION: We present a case of prenatal diagnosis with parental exome sequencing, which successfully diagnosed the carrier status of the fetus and parents in a combined methylmalonic acidemia and homocystinuria family.

Methotrexate polyglutamate quantification for clinical application in patients with pediatric acute lymphoblastic leukemia in association with genetic polymorphisms.

We developed and validated a quantification method for methotrexate (MTX) polyglutamates (MTX-PGs, MTX-PG1 to MTX-PG5) by liquid chromatography-tandem mass spectrometry using stable isotope-labeled internal standards and applied to 196 clinical samples collected from pediatric acute lymphoblastic leukemia patients treated with MTX. MTX-PGs levels and their proportions (%) in sum of all MTX-PGs (MTXSum) were evaluated in relation to TPMT, NUDT15, and MTHFR genotypes. For the developed method, linearity ranges 1-500 nmol/L, bias for accuracy 0.3-13.5 %, coefficient of variation for within- and between-run imprecision of 3.2-9.5% and 1.5-12.0%, respectively. Recoveries achieved were 74.2-105.8 %. There was no significant carryover. The median level of the MTXSum for 196 clinical samples was 129.4 nmol/L (interquartile range 28.1-241.2). MTX dose and MTX-PGs were associated (P < 0.05) and among five MTX-PGs, MTX-PG3 was the predominant form (median 41.7 %). The MTX-PG3 level was significantly higher in patients with TPMT *1/*3C than in patients with wild type and MTX-PG3% was significantly higher and MTX-PG5% was significantly lower in NUDT15 intermediate metabolizers than normal or indeterminate phenotypes (P < 0.05). This validated MTX-PGs quantification method can facilitate a better understanding of MTX metabolism and therapeutic drug monitoring for MTX treatment.

Test Utilization for Thyroglobulin and Anti-Thyroglobulin Antibody Assays in Korea.

BACKGROUND: When measuring thyroglobulin (Tg), simultaneous measurement of Tg autoantibodies (Ab) is recommended by clinical guidelines for follow-up of patients with differentiated thyroid cancers after thyroidectomy and radioactive iodine ablation. We aimed to investigate test utilization of Tg and Tg Ab assays in local clinics and hospitals in Korea. METHODS: We retrospectively reviewed data from the laboratory information system between November 6, 2017 and December 31, 2019. RESULTS: During the study period, 10,551 Tg tests were performed on 2,592 Korean adults from 97 local clinics and hospitals. Among them, 3,924 (37.2%) test results lacked concurrent Tg Ab assays, while 6,627 test results had concurrently measured Tg Ab, and 528 (8.0%) showed positive Tg Ab results, which could interfere with measurement of Tg concentration. CONCLUSIONS: The results of this study provide basic information regarding test utilization of Tg Ab assays to improve test utilization for accurate Tg measurement in Korean patients.

DNA-thioguanine nucleotide as a treatment marker in acute lymphoblastic leukemia patients with NUDT15 variant genotypes.

BACKGROUND: Large inter-individual variations in drug metabolism pose a challenge in determining 6-mercaptopurine (6MP) doses. As the last product of 6MP metabolism, DNA-thioguanine nucleotide (DNA-TGN) could reflect the efficacy of 6MP, especially in patients harboring variants in the 6MP metabolism pathway. The aim of this study was to investigate the clinical significance of DNA-TGN monitoring in Korean pediatric acute lymphoblastic leukemia (ALL) patients, focusing on the NUDT15 genotype. METHODS: The subjects of this study were patients who underwent ALL treatment with 6MP. Tests for the NUDT15 and TPMT genotypes were performed, and prospective DNA-TGN and erythrocyte TGN samples were collected after two weeks or more of 6MP treatment. DNA-TGN was quantified using the liquid chromatography-tandem mass spectrometry method. RESULTS: A total of 471 DNA-TGN measurements in 71 patients were analyzed, which ranged from 1.0 to 903.1 fmol thioguanine/µg DNA. The 6MP intensity demonstrated a significant relationship with DNA-TGN concentration (P<0.001). Patients harboring NUDT15 variants were treated with a lower dose of 6MP (P<0.001); however, there was no significant difference in DNA-TGN concentration when compared to patients carrying wild-type NUDT15 (P = 0.261). These patients also presented higher variation in DNA-TGN levels (P = 0.002) and DNA-TGN/6MP intensity (P = 0.019) compared to patients carrying wild-type NUDT15. DNA-TGN concentration did not show a significant correlation with WBC count (P = 0.093). CONCLUSIONS: Patients harboring NUDT15 variants demonstrated similar DNA-TGN concentrations even at low doses of 6MP and showed high variability in DNA-TGN. Particularly in patients with NUDT15 variants who need a reduced 6MP dose, DNA-TGN could be applied as a useful marker to monitor the therapeutic effect of 6MP.

Quantification of Thioguanine in DNA Using Liquid Chromatography-Tandem Mass Spectrometry for Routine Thiopurine Drug Monitoring in Patients With Pediatric Acute Lymphoblastic Leukemia.

BACKGROUND: We developed an assay to measure DNA-incorporated 6-thioguanine (DNA-TG) and validated its clinical applicability in Korean pediatric patients with acute lymphoblastic leukemia (ALL) in order to improve individualized thiopurine treatment and reduce the life-threatening cytotoxicity. METHODS: The DNA-TG assay was developed based on liquid chromatography-tandem mass spectrometry, with isotope-labeled TG-d3 and guanine-d3 as internal standards. This method was applied to 257 samples of pediatric ALL patients. The DNA-TG level was compared with erythrocyte TG nucleotide (RBC-TGN) level in relation to the TPMT and NUDT15 genotypes, which affect thiopurine metabolism, using Spearman's rank test and repeated measure ANOVA. RESULTS: For DNA-TG quantification, a linearity range of 10.0-5,000.0 fmol TG/µg DNA; bias for accuracy of -10.4% -3.5%; coefficient of variation for intra- and inter-day precision of 3.4% and 5.8% at 80 fmol TG/µg DNA and of 4.9% and 5.3% at 800 fmol TG/µg DNA, respectively; and recovery of 85.7%-116.2% were achieved without matrix effects or carry-over. The median DNA-TG level in the 257 samples was 106.0 fmol TG/µg DNA (interquartile range, 75.8-150.9). There was a strong correlation between DNA-TG and RBC-TGN levels (ρ=0.68, P<0.0001). The DNA-TG/RBC-TGN ratio was significantly higher in NUDT15 intermediate metabolizers (*1/*2 and *1/*3) than in patients with wild-type alleles (P<0.0001). CONCLUSIONS: This simple and sensitive method for measuring DNA-TG level can improve therapeutic drug monitoring for thiopurine treatment.

Serum Vitamin Levels and Their Relationships with Other Biomarkers in Korean Breast Cancer Patients.

Numerous studies have shown that vitamins reduce the risk of cancers, but the relationship between serum vitamin levels and breast cancer is still controversial. In this study, we evaluated serum levels of vitamins in Korean patients with benign breast disease or breast cancer and investigated their associations with clinical and laboratory parameters. Concentrations of vitamin A, D, and E, together with homocysteine and methylmalonic acid as biomarkers of vitamin B12 deficiency, were measured by high-performance liquid chromatography (HPLC) or liquid chromatography with tandem mass spectrometry (LC-MS/MS) in the serum of 104 breast cancer patients, 62 benign breast disease patients, and 75 healthy Korean females. We further assessed possible associations between vitamin levels and breast cancer subtypes, the presence of lymph node metastasis, and tumor stages. Serum concentrations of vitamins A and E were significantly lower in breast cancer patients and in benign breast disease patients than in healthy controls. Severe vitamin D deficiency was more prevalent in breast cancer patients than in healthy controls. Vitamin D level was significantly lower in breast cancer patients with estrogen receptor-negative or triple-negative subtypes than in those with other subtypes. Further research with a larger study population is required to elucidate the role of vitamins in breast cancer.

Preeclampsia Screening Using the Ratio of Soluble FMS-Like Tyrosine Kinase-1 to Placental Growth Factor During Pregnancy in Pregnant Korean Women.

BACKGROUND: We retrospectively investigated soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) ratios and screen-positive rates according to cutoff values for preeclampsia risk assessment based on the number of fetuses. METHODS: sFlt-1/PlGF ratios < 38.0 and < 53.0 were defined as low risk of preeclampsia (screen negative) for singleton and twin pregnancies, respectively. RESULTS: During the study period, 442 test results from 403 pregnant women (374 with singleton and 29 twin pregnancies) from 32 local clinics and hospitals were analyzed. The overall rate of positive preeclampsia screening was 25.1% and this rate was higher when gestational age was ≥ 34 weeks than when it was < 34 weeks (58.7% vs. 18.6%, p < 0.05). Among 34 women with follow-up results, a change in interpretation category was observed during the follow-up period at ≥ 4.8 weeks for singleton and ≥ 1.6 weeks for twin pregnancies, respectively. CONCLUSIONS: This study may help to understand the sFlt-1/PlGF ratio in pregnant Korean women.

Effects of various genetic polymorphisms on thiopurine treatment-associated outcomes for Korean patients with Crohn's disease.

AIMS: This study explores the effects of various genetic polymorphisms in candidate genes on thiopurine metabolism and toxicity in adult patients with Crohn's disease in Korea. METHODS: A total of 131 adult patients with Crohn's disease receiving thiopurine treatment were included. The TPMT and NUDT15 genes and an additional 116 genetic polymorphisms (in 40 genes and 3 intergenic locations) were screened for genotyping. Among the polymorphisms screened, 91 genetic polymorphisms (in 34 genes and 3 intergenic locations) in addition to TPMT and NUDT15 genotypes were included for statistical analyses to investigate their effects on thiopurine metabolites and adverse outcomes (leukopenia, hepatotoxicity, gastrointestinal intolerance, skin rash and alopecia). RESULTS: The median duration of thiopurine treatment was 47.0 months (range 6.0-153.4 months). Patient sex, maintenance dose of thiopurine, and use of anti-tumour necrosis factor agents were associated with thiopurine metabolite concentrations (P < .05). In the univariate analysis, the TPMT genotype was associated with 6-thioguanine level (P < .05), although the significance of this did not remain in multivariate analysis. Genetic polymorphisms in the ATIC (rs3821353 and rs16853834), IMPDH2 (rs11706052) and ITPA (rs6139036) genes were associated with thiopurine metabolism (P < .05). Genetic polymorphisms in the ABCC5 (rs8180093) and NUDT15 genotypes were associated with leukopenia (P < .05). CONCLUSION: The results of this study may help clinicians to understand the effects of other various polymorphisms in addition to TPMT and NUDP15 in thiopurine metabolism for management of Crohn's disease patients.

Pathway genes and metabolites in thiopurine therapy in Korean children with acute lymphoblastic leukaemia.

AIMS: We aimed to investigate the impact of various genetic polymorphisms affecting thiopurine metabolism pathways and toxicity in paediatric acute lymphoblastic leukaemia patients for the first time in Korea. METHODS: From May 2006 to September 2016, 139 paediatric acute lymphoblastic leukaemia patients treated with combination chemotherapy including 6-mercaptopurine were included in the study. One hundred and twenty-three variants in 43 genes, including TMPT and NUDT15, were screened using targeted genotyping, such as a MassARRAY system, direct sequencing and polymerase chain reaction-restriction fragment length polymorphism methods. Among the polymorphisms screened, 103 polymorphisms of 43 genes were included for further analyses. RESULTS: The genetic polymorphisms in the ABCC4, AHCY, ATIC, FAM8A6P, GART, GNG2, GSTA1, MTHFD1, MTHFR, NUDT15, PACSIN2, TYMS and XDH genes, and an intronic polymorphism between HIVEP2 and AIG1, and TPMT genotype were associated with thiopurine metabolism (P < 0.05). Genetic polymorphisms in the ABCC4, ADK, ATIC, GART, GMPS, GSTP1, IMPDH1, ITPA, KCNMA1, MOCOS, MTRR, NUDT15, SLC19A1, SLC28A3, SLC29A1, SLCO1B1, TYMP and XDH genes were associated with thiopurine-related toxicities; neutropenia, hepatotoxicity and treatment interruption (P < 0.05). CONCLUSIONS: Findings of this study may provide basic knowledge for personalized medicine for thiopurinxe treatment in paediatric acute lymphoblastic leukaemia patients.

Evaluation of the Serum Mac-2 Binding Protein Glycosylation Isomer Test used for Diagnosis and Monitoring of Liver Fibrosis and the Correlation of Mac-2 Binding Protein Glycosylation Isomer with Hemoglobin A1c.

BACKGROUND: Our aims in this study were to evaluate the performance of the Mac-2 binding protein glycosylation isomer (M2BPGi), a liver fibrosis marker, using Sysmex HISCL following user verification guidelines before clinical use. We also evaluated the correlation between M2BPGi and hemoglobin A1c (HbA1c) because HbA1c is known as another biomarker associated with glycosylation. METHODS: The analytical performance of M2BPGi was verified following user verification guidelines by the Clinical and Laboratory Standards Institute. RESULTS: A qualitative, precision experiment for analyte concentrations near the cutoff was verified using quality control materials. The manufacturer's precision claims for the quantitative cutoff index were verified, with coefficients of variation in the range of 1.83 - 4.12%. HbA1c did not significantly contribute to M2BPGi in a multivariate analysis with an age factor. CONCLUSIONS: The analytical performance of M2BPGi in our results verify the manufacturer's claims. Clinical information and other findings, including HbA1c, are needed for clinical applications.

Serum Trace Elements and Their Associations with Breast Cancer Subgroups in Korean Breast Cancer Patients.

The relationships between serum levels of trace elements and breast cancer remain relatively unknown. In this study, we investigate serum levels of seven trace elements in Korean breast cancer patients compared to controls without breast cancer. Serum trace element levels were determined using inductively coupled plasma mass spectrometry in Korean breast cancer patients before initiation of breast cancer treatment. Korean females without breast cancer served as a control group. Trace element levels were measured in the discovery cohort (n = 287) and were validated in an independent cohort (n = 142). We further investigated possible associations between trace element levels and the presence of lymph node metastasis, distant metastasis, or triple-negative breast cancer among breast cancer patients in subgroup analyses. Serum manganese and molybdenum levels were significantly higher (p < 0.05) in breast cancer patients than in controls. Serum copper levels were significantly higher in breast cancer patients with distant metastasis, while selenium levels were significantly lower. Other trace elements were neither significantly different between breast cancer patients and controls nor between subgroups of breast cancer patients. Our study provides insights about the potential roles and impacts of trace elements through an assessment of the associations between trace elements and breast cancer.

NUDT15 Variants Cause Hematopoietic Toxicity with Low 6-TGN Levels in Children with Acute Lymphoblastic Leukemia.

PURPOSE: We aimed to identify the impact of NUDT15 variants on thiopurine intolerance and 6-thioguanine nucleotide (6-TGN) levels in Korean children with acute lymphoblastic leukemia (ALL). MATERIALS AND METHODS: Genotyping of NUDT15 was tested in 258 patients with ALL registered at Samsung Medical Center. Patients were classified into normal-activity (wild-type), intermediate-activity (heterozygous variant), and low-activity groups (homozygous or compound heterozygous variant). Clinical and laboratory features during the first year of maintenance therapy were investigated. RESULTS: A total of 182 patients were included in the final analysis. There were five (2.7%), 46 (25.3%), and 131 (72.0%) patients in low-, intermediate-, and normal-activity groups, respectively. The lowest 6-mercaptopurine (6-MP) dose (mg/m2/day) was administered to the low-activity group (low-activity group 7.5 vs. intermediate-activity group 24.4 vs. normalactivity group 31.1, p < 0.01) from three months to a year after beginning maintenance therapy. The low-activity group experienced the longest duration of therapy interruption during the first year (low-activity group 169 days vs. intermediate-activity group 30 days vs. normal-activity group 16 days, p < 0.01). They also showed the lowest blood cell counts and had a longer duration of leukopenia (low-activity group 131 days vs. intermediate-activity group 92 days vs. normal-activity group 59 days, p < 0.01). 6-TGN level and its ratio to 6-MP dose were lowest in the low-activity group. CONCLUSION: NUDT15 variants cause hematopoietic toxicity with low 6-TGN levels. NUDT15 genotyping should be conducted before administering thiopurine, and dose adjustments require caution regardless of 6-TGN levels.

Serum inflammatory profiles in pulmonary tuberculosis and their association with treatment response.

The aim of this study was to evaluate serum cytokines and natural antimicrobial peptide profiles in pulmonary tuberculosis, and compare them with levels in controls without tuberculosis, to explore the associations between these biomarkers and response to antituberculosis treatment. Serum levels of 10 biomarkers were measured using a Luminex bead array platform. Tuberculosis biosignatures were identified from the discovery cohort (n=148) and were validated in the independent cohort (n=148). Association between biosignatures and clinical outcome was investigated with negative conversion in follow-up sputum culture after 2months of treatment. Serum concentrations of eotaxin, MIP-1α, sIL-2Rα, and lipocalin 2 were significantly different between pulmonary tuberculosis patients and controls (P<0.05). Serum concentrations of eotaxin and sIL-2Rα were higher in pulmonary tuberculosis patients than in controls, while those of MIP-1α and lipocalin 2 were lower (P<0.05). Eotaxin concentrations were significantly higher in good responders to treatment (P<0.05), indicating this immunomolecule may serve as a positive predictor for therapy response in pulmonary tuberculosis. The magnitude serum eotaxin, MIP-1α, sIL-2Rα, and lipocalin 2 are important indicators for pulmonary tuberculosis. These biomarkers alone or combinatorial detections have potential applicability in monitoring tuberculosis patients during antituberculosis treatment. SIGNIFICANCE: Cytokines and endogenous antimicrobial peptides represent an important part of immune system and the identification of a pattern of differentially expressed those biomarkers (a "biosignature") could help to differentiate tuberculosis infection from the non-infected state which might eventually assist case identification and accelerate access to treatment. In this direction, cytokine analysis including multiple serum biomarkers to evaluate biosignatures of pulmonary tuberculosis would provide basic knowledge to aid understanding of the pathophysiology of tuberculosis infection and for the development of future diagnostic methods, treatments, and monitoring for pulmonary tuberculosis.