An aged immune system drives senescence and ageing of solid organs.

Ageing of the immune system, or immunosenescence, contributes to the morbidity and mortality of the elderly1,2. To define the contribution of immune system ageing to organism ageing, here we selectively deleted Ercc1, which encodes a crucial DNA repair protein3,4, in mouse haematopoietic cells to increase the burden of endogenous DNA damage and thereby senescence5-7 in the immune system only. We show that Vav-iCre+/-;Ercc1-/fl mice were healthy into adulthood, then displayed premature onset of immunosenescence characterized by attrition and senescence of specific immune cell populations and impaired immune function, similar to changes that occur during ageing in wild-type mice8-10. Notably, non-lymphoid organs also showed increased senescence and damage, which suggests that senescent, aged immune cells can promote systemic ageing. The transplantation of splenocytes from Vav-iCre+/-;Ercc1-/fl or aged wild-type mice into young mice induced senescence in trans, whereas the transplantation of young immune cells attenuated senescence. The treatment of Vav-iCre+/-;Ercc1-/fl mice with rapamycin reduced markers of senescence in immune cells and improved immune function11,12. These data demonstrate that an aged, senescent immune system has a causal role in driving systemic ageing and therefore represents a key therapeutic target to extend healthy ageing.

Polyubiquitinated PCNA triggers SLX4-mediated break-induced replication in alternative lengthening of telomeres (ALT) cancer cells.

Replication stresses are the major source of break-induced replication (BIR). Here, we show that in alternative lengthening of telomeres (ALT) cells, replication stress-induced polyubiquitinated proliferating cell nuclear antigen (PCNA) (polyUb-PCNA) triggers BIR at telomeres and the common fragile site (CFS). Consistently, depleting RAD18, a PCNA ubiquitinating enzyme, reduces the occurrence of ALT-associated promyelocytic leukemia (PML) bodies (APBs) and mitotic DNA synthesis at telomeres and CFS, both of which are mediated by BIR. In contrast, inhibiting ubiquitin-specific protease 1 (USP1), an Ub-PCNA deubiquitinating enzyme, results in an increase in the above phenotypes in a RAD18- and UBE2N (the PCNA polyubiquitinating enzyme)-dependent manner. Furthermore, deficiency of ATAD5, which facilitates USP1 activity and unloads PCNAs, augments recombination-associated phenotypes. Mechanistically, telomeric polyUb-PCNA accumulates SLX4, a nuclease scaffold, at telomeres through its ubiquitin-binding domain and increases telomere damage. Consistently, APB increase induced by Ub-PCNA depends on SLX4 and structure-specific endonucleases. Taken together, our results identified the polyUb-PCNA-SLX4 axis as a trigger for directing BIR.

Short-range end resection requires ATAD5-mediated PCNA unloading for faithful homologous recombination.

Homologous recombination (HR) requires bidirectional end resection initiated by a nick formed close to a DNA double-strand break (DSB), dysregulation favoring error-prone DNA end-joining pathways. Here we investigate the role of the ATAD5, a PCNA unloading protein, in short-range end resection, long-range resection not being affected by ATAD5 deficiency. Rapid PCNA loading onto DNA at DSB sites depends on the RFC PCNA loader complex and MRE11-RAD50-NBS1 nuclease complexes bound to CtIP. Based on our cytological analyses and on an in vitro system for short-range end resection, we propose that PCNA unloading by ATAD5 is required for the completion of short-range resection. Hampering PCNA unloading also leads to failure to remove the KU70/80 complex from the termini of DSBs hindering DNA repair synthesis and the completion of HR. In line with this model, ATAD5-depleted cells are defective for HR, show increased sensitivity to camptothecin, a drug forming protein-DNA adducts, and an augmented dependency on end-joining pathways. Our study highlights the importance of PCNA regulation at DSB for proper end resection and HR.

A uniform conditioning regimen of busulfan, fludarabine, and antithymocyte globulin for allogeneic haematopoietic cell transplantation from haploidentical family, matched sibling, or unrelated donors-A single-centre, prospective, explorative study.

In a prospective, explorative study, the donor-source difference of haploidentical family (HF), matched sibling (MS), and unrelated donors (UD) was evaluated for the outcome of haematopoietic cell transplantations (HCT) in 101 patients with acute myeloid leukaemia (AML) in complete remission (CR). To eliminate compounding effects, a uniform conditioning regimen containing antithymocyte globulin (ATG) was used. After transplantation, there was a significantly higher cumulative incidence of acute graft-versus-host disease (GVHD) in HF-HCT patients (49%, 7%, and 16% for HF-, MS- and UD-HCT respectively; p < 0.001). A quarter of acute GVHD cases observed in HF-HCT patients occurred within three days of engraftment and were characterized by diffuse skin rash, fever, weight gain, and hypoalbuminaemia. This peri-engraftment acute GVHD was not observed in MS-HCT or UD-HCT patients. Additionally, a significantly higher proportion of HF-HCT patients achieved complete donor chimaerism in the peripheral mononuclear cells at one month (88%, 46%, and 69% for HF-, MS- and UD-HCT respectively; p = 0.001). There was no significant difference in engraftment, chronic GVHD, leukaemia recurrence, non-relapse mortality, and patient survival. In patients with AML in CR who received HCT using ATG-containing conditioning, stronger donor-patient alloreactivity was observed in HF-HCT, in terms of increased acute GVHD and higher likelihood of complete donor chimaerism.

Natural Killer Cell Activity Test Helps to Suspect Aggressive Natural Killer Cell Leukemia - Diagnostic Challenge.

Aggressive natural killer cell leukemia (ANKL) is a rare disease with an aggressive clinical course. We aimed to assess the clinicopathological characteristics of the difficult to diagnose ANKL. During ten years, nine patients with ANKL were diagnosed. All the patients exhibited aggressive clinical course and underwent the BM study to rule out lymphoma and hemophagocytic lymphohistiocytosis (HLH). BM examination showed varying degrees of infiltration of neoplastic cells, which were mainly positive for CD2, CD56, cytoplasmic CD3 and EBV in situ hybridization. Five BM aspirates showed histiocytic proliferation with active heomphagocytosis. Normal or increased NK cell activity test results were obtained from 3 patients who were available for testing. Four had multiple BM studies until diagnosis. An aggressive clinical course and positive EBV in situ hybridization, often with associated secondary HLH, should raise the suspicion of an ANKL. Conducting additional supplementary tests such as NK cell activity and NK cell proportion would be helpful for the diagnosis of ANKL.

Timely termination of repair DNA synthesis by ATAD5 is important in oxidative DNA damage-induced single-strand break repair.

Reactive oxygen species (ROS) generate oxidized bases and single-strand breaks (SSBs), which are fixed by base excision repair (BER) and SSB repair (SSBR), respectively. Although excision and repair of damaged bases have been extensively studied, the function of the sliding clamp, proliferating cell nuclear antigen (PCNA), including loading/unloading, remains unclear. We report that, in addition to PCNA loading by replication factor complex C (RFC), timely PCNA unloading by the ATPase family AAA domain-containing protein 5 (ATAD5)-RFC-like complex is important for the repair of ROS-induced SSBs. We found that PCNA was loaded at hydrogen peroxide (H2O2)-generated direct SSBs after the 3'-terminus was converted to the hydroxyl moiety by end-processing enzymes. However, PCNA loading rarely occurred during BER of oxidized or alkylated bases. ATAD5-depleted cells were sensitive to acute H2O2 treatment but not methyl methanesulfonate treatment. Unexpectedly, when PCNA remained on DNA as a result of ATAD5 depletion, H2O2-induced repair DNA synthesis increased in cancerous and normal cells. Based on higher H2O2-induced DNA breakage and SSBR protein enrichment by ATAD5 depletion, we propose that extended repair DNA synthesis increases the likelihood of DNA polymerase stalling, shown by increased PCNA monoubiquitination, and consequently, harmful nick structures are more frequent.

TonEBP recognizes R-loops and initiates m6A RNA methylation for R-loop resolution.

R-loops are three-stranded, RNA-DNA hybrid, nucleic acid structures produced due to inappropriate processing of newly transcribed RNA or transcription-replication collision (TRC). Although R-loops are important for many cellular processes, their accumulation causes genomic instability and malignant diseases, so these structures are tightly regulated. It was recently reported that R-loop accumulation is resolved by methyltransferase-like 3 (METTL3)-mediated m6A RNA methylation under physiological conditions. However, it remains unclear how R-loops in the genome are recognized and induce resolution signals. Here, we demonstrate that tonicity-responsive enhancer binding protein (TonEBP) recognizes R-loops generated by DNA damaging agents such as ultraviolet (UV) or camptothecin (CPT). Single-molecule imaging and biochemical assays reveal that TonEBP preferentially binds a R-loop via both 3D collision and 1D diffusion along DNA in vitro. In addition, we find that TonEBP recruits METTL3 to R-loops through the Rel homology domain (RHD) for m6A RNA methylation. We also show that TonEBP recruits RNaseH1 to R-loops through a METTL3 interaction. Consistent with this, TonEBP or METTL3 depletion increases R-loops and reduces cell survival in the presence of UV or CPT. Collectively, our results reveal an R-loop resolution pathway by TonEBP and m6A RNA methylation by METTL3 and provide new insights into R-loop resolution processes.

Five-day versus 7-day treatment regimen with azacitidine in lower risk myelodysplastic syndrome: A phase 2, multicenter, randomized trial.

BACKGROUND: Low-dose azacitidine (AZA) regimens, primarily 5-day AZA, have been used in lower risk myelodysplastic syndrome (LrMDS) but they have yet to be directly compared to the standard 7-day, uninterrupted dosing schedule. METHOD: In this phase 2, multicenter, randomized trial, 55 patients with adult LrMDS (low and intermediate-1 risk by international prognostic scoring system [IPSS]) were randomly assigned and received either 5-day (n = 26) or 7-day (n = 29) AZA between March 2012 and August 2020. The trial was stopped prematurely because of the slow accrual of patients. The primary end point was the overall response rate (ORR) of the 5-day AZA as compared to that of the 7-day regimen. RESULTS: Median patient age was 59 years, and IPSS intermediate-1 risk comprised the majority (81.8%). The median number of cycles in both arms was six. In the ITT subset (n = 53), in each of the 5-day and 7-day arms, the ORR of 48.0% and 39.3%, hematologic improvement of 44.0% and 39.3%, and RBC transfusion independence of 35.3% and 40.0% were observed respectively, and none of these findings were significantly different between the two arms. A cytogenetic response rate was significantly higher in the 7-day arm (8.3% and 53.8%, p = .027). Survival and adverse events were similar between the groups, although gastrointestinal toxicities, grade ≥3 thrombocytopenia, and febrile neutropenia were less frequent in the 5-day arm. CONCLUSION: The 5-day AZA in LrMDS showed comparable efficacy to a 7-day regimen in terms of similar overall response and other outcomes, despite significantly higher rates of cytogenetic responses in the 7-day regimen. LAY SUMMARY: Azacitidine (75 mg/m2 /day for 7 consecutive days per 28-day cycle) has shown survival benefit in patients with higher risk myelodysplastic syndrome (MDS). Although the use of azacitidine is less-well studied for lower risk MDS, it is generally accepted as a feasible option for lower risk MDS (LrMDS).

Clinical implications and genetic features of clonal cytopenia of undetermined significance compared to lower-risk myelodysplastic syndrome.

Clonal cytopenia of undetermined significance (CCUS) is characterized by persistent cytopenias with genetic aberrations, which do not meet the diagnostic criteria for myelodysplastic syndrome (MDS). We aimed to compare the clinical and genetic characteristics of CCUS with lower-risk MDS and identify patients with CCUS with a high risk of progression. We performed targeted sequencing of bone marrow (BM) samples from patients with idiopathic cytopenia of undetermined significance (ICUS) (n = 139) and MDS (n = 226). Overall survival (OS) of patients with CCUS (n = 78) was worse than non-clonal ICUS (n = 61) and superior to lower-risk MDS (n = 99). Patients with CCUS showed similar characteristics to those with lower-risk MDS, except for higher haemoglobin, lower BM cellularity, and less frequent SF3B1 mutations. Lower haemoglobin, DDX41 (biallelic germline and somatic), ETV6, and RUNX1 mutations were independent prognostic factors for worse OS. Lower haemoglobin and DDX41 mutations were also associated with lower progression-free survival. Patients with CCUS with high-risk features showed similar or worse OS than patients with lower-risk MDS. Our findings suggest that patients with CCUS having certain clinical or genetic features should be regarded and treated as lower-risk MDS despite lacking significant dysplasia or MDS-associated chromosomal abnormalities.

Unique ethnic features of DDX41 mutations in patients with idiopathic cytopenia of undetermined significance, myelodysplastic syndrome, or acute myeloid leukemia.

DDX41 mutations are associated with hematologic malignancies including myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but the incidence in idiopathic cytopenia of undetermined significance (ICUS) is unknown. We investigated the incidence, genetic characteristics, and clinical features of DDX41 mutations in Korean patients with ICUS, MDS, or AML. We performed targeted deep sequencing of 61 genes including DDX41 in 457 patients with ICUS (n=75), MDS (n=210), or AML (n=172). Germline DDX41 mutations with causality were identified in 28 (6.1%) patients, of whom 27 (96.4%) had somatic mutations in the other position of DDX41. Germline origins of the DDX41 mutations were confirmed in all of the 11 patients in whom germline-based testing was performed. Of the germline DDX41 mutations, p.V152G (n=10) was most common, followed by p.Y259C (n=8), p.A500fs (n=6), and p.E7* (n=3). Compared with non-mutated patients, patients with a DDX41 mutation were more frequently male, older, had a normal karyotype, low leukocyte count, and hypocellular marrow at diagnosis. Three of the four ICUS patients with germline DDX41 mutations progressed to MDS. The incidence of DDX41 mutations in Korean patients was high and there was a distinct mutation pattern, in that p.V152G was a unique germline variant. ICUS harboring germline DDX41 mutations may be regarded as a hereditary myeloid neoplasm. Germline DDX41 mutations are not uncommon and should be explored when treating patients with myeloid malignancies.

ATAD5 restricts R-loop formation through PCNA unloading and RNA helicase maintenance at the replication fork.

R-loops are formed when replicative forks collide with the transcriptional machinery and can cause genomic instability. However, it is unclear how R-loops are regulated at transcription-replication conflict (TRC) sites and how replisome proteins are regulated to prevent R-loop formation or mediate R-loop tolerance. Here, we report that ATAD5, a PCNA unloader, plays dual functions to reduce R-loops both under normal and replication stress conditions. ATAD5 interacts with RNA helicases such as DDX1, DDX5, DDX21 and DHX9 and increases the abundance of these helicases at replication forks to facilitate R-loop resolution. Depletion of ATAD5 or ATAD5-interacting RNA helicases consistently increases R-loops during the S phase and reduces the replication rate, both of which are enhanced by replication stress. In addition to R-loop resolution, ATAD5 prevents the generation of new R-loops behind the replication forks by unloading PCNA which, otherwise, accumulates and persists on DNA, causing a collision with the transcription machinery. Depletion of ATAD5 reduces transcription rates due to PCNA accumulation. Consistent with the role of ATAD5 and RNA helicases in maintaining genomic integrity by regulating R-loops, the corresponding genes were mutated or downregulated in several human tumors.

Second allogeneic hematopoietic stem cell transplantation in patients with acute leukemia relapsed after allogeneic hematopoietic stem cell transplantation.

The prognosis of patients with acute leukemia relapsed after allogeneic hematopoietic stem cell transplantation (HSCT) is dismal. We aimed to evaluate the outcomes and prognostic factors of the second HSCT (HSCT2) in acute leukemia patients relapsed after the first HSCT (HSCT1). We analyzed 80 patients who received HSCT2 for relapsed acute leukemia in two Korean institutes. All but four patients received HSCT2 from a donor other than matched sibling donor: an unrelated donor (URD) in 30 and a familial haploidentical donor (FHD) in 46. Forty-four patients (55.0%) were in complete remission (CR) or CR with incomplete count recovery (CRi) at HSCT2, and the median time from HSCT1 to relapse was 9 months. The 2-year overall survival (OS) and event-free survival (EFS) were 21.0% and 17.5%, respectively. The outcomes were similar between URD and FHD. Multivariate analysis demonstrated that disease status (active disease vs. CR/CRi) at HSCT2 and remission duration after HSCT1 were independent prognostic factors for OS and EFS after HSCT2. HSCT2 from URD or FHD was feasible in patients with acute leukemia relapsed after allogeneic HSCT. Also, our study confirmed two critical prognostic factors; disease status at HSCT2 and remission duration after HSCT1.

Diagnostic yield of a bronchoalveolar lavage fluid galactomannan assay in patients with negative serum galactomannan results suspected to have invasive pulmonary aspergillosis.

BACKGROUND AND OBJECTIVES: There are limited data in real clinical practice on the diagnostic value of a bronchoalveolar lavage (BAL) fluid galactomannan (GM) assay in patients with suspected invasive pulmonary aspergillosis (IPA) who had negative serum GM results. Thus, we investigated the diagnostic performance of a BAL GM assay in patients with negative serum GM assay results who were suspected to have IPA. METHODS: This retrospective study was performed between May 2008 and April 2019 at a tertiary-care hospital in Seoul, South Korea. All patients with suspected IPA whose serum GM assays revealed negative results who sequentially underwent BAL were enrolled in this study. RESULTS: A total of 341 patients with suspected IPA including four cases of proven IPA, 38 cases of probable IPA, 107 cases of possible IPA and 192 patients without IPA were enrolled. Of these 341 patients, 107 (31%) with possible IPA were excluded from the final analysis. Of 42 patients with proven and probable IPA who had initial negative serum GM results, 24 (57%) had positive BAL GM results (n = 24) or BAL fungal culture results (n = 8). In addition, BAL revealed evidence of other opportunistic infections including Pneumocystis jirovecii pneumonia (14% [26/190]), cytomegalovirus (CMV) pneumonia (5% [9/188]) and respiratory viral pneumonia (6% [12/193]). CONCLUSION: Sequential BAL in patients with suspected IPA who had initial negative serum GM results provided additional diagnostic yield in approximately half of patients with evidence of another co-infection.

A Case Report of Immune Thrombocytopenia after ChAdOx1 nCoV-19 Vaccination.

Immune thrombocytopenia (ITP) is an autoimmune condition characterized by platelet destruction through antibody-mediated mechanism. ITP is one of the manifestations of a coronavirus disease, as well as an adverse event occurring after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several cases of ITP have been described after vaccination with two mRNA-based vaccines-BTN162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna)-against SARS-CoV-2. Herein, we report a case of ITP occurring after vaccination with ChAdOx1 adenovirus vector nCoV-19 (AstraZeneca) vaccine in Korea. A 66-year-old woman presented with multiple ecchymoses on both upper and lower extremities and gingival bleeding, appearing 3 days after receiving the first dose of ChAdOx1 nCoV-19. Her laboratory results showed isolated severe thrombocytopenia without evidence of combined coagulopathy. She was diagnosed with ITP and successfully treated with high-dose dexamethasone and intravenous immunoglobulin. Clinical suspicion to identify vaccine-related ITP is important to promptly initiate appropriate treatment.

Incidence, Management, and Prognosis of Graft Failure and Autologous Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation.

BACKGROUND: This study presents outcomes of management in graft failure (GF) after allogeneic hematopoietic stem cell transplantation (HCT) and provides prognostic information including rare cases of autologous reconstitution (AR). METHODS: We analyzed risk factors and outcomes of primary and secondary GF, and occurrence of AR in 1,630 HCT recipients transplanted over period of 18 years (January 2000-September 2017) at our center. RESULTS: Primary and secondary GF occurred in 13 (0.80%), and 69 patients (10-year cumulative incidence, 4.5%) respectively. No peri-transplant variables predicted primary GF, whereas reduced intensity conditioning (RIC) regimen (relative risk [RR], 0.97-28.0, P < 0.001) and lower CD34⁺ cell dose (RR, 2.44-2.84, P = 0.002) were associated with higher risk of secondary GF in multivariate analysis. Primary GF demonstrated 100% mortality, in the secondary GF group, the 5-year Kaplan-Meier survival rate was 28.8%, relapse ensued in 18.8%, and AR was observed in 11.6% (n = 8). In survival analysis, diagnosis of aplastic anemia (AA), chronic myeloid leukemia and use of RIC had a positive impact. There were 8 patients who experienced AR, which was rarely reported after transplantation for acute leukemia. Patient shared common characteristics such as young age (median 25 years), use of RIC regimen, absence of profound neutropenia, and had advantageous survival rate of 100% during follow period without relapse. CONCLUSION: Primary GF exhibited high mortality rate. Secondary GF had 4.5% 10-year cumulative incidence, median onset of 3 months after HCT, and showed 5-year Kaplan-Meier survival of 28.8%. Diagnosis of severe AA and use of RIC was both associated with higher incidence and better survival rate in secondary GF group. AR occurred in 11.6% in secondary GF, exhibited excellent prognosis.

Treatment of Latent Tuberculosis Infection Based on the Interferon-γ Release Assay in Allogeneic Stem Cell Transplant Recipients.

In hematopoietic stem cell transplant recipients, the incidence of tuberculosis in positive interferon-γ release assay (IGRA) without isoniazid prophylaxis (3.58/100 person-years) was higher than in negative or indeterminate IGRA (1.15/100 person-years; P = .01) and in positive IGRA with isoniazid prophylaxis (0/100 person-years; P = .09). The number needed to treat was 22 (95% confidence interval, 12-99) with positive IGRA results.

Immunodeficiency risk score for prediction of mortality by parainfluenza virus infection in patients with hematologic malignancy.

Parainfluenza virus (PIV) infection is a significant cause of morbidity and mortality, especially in hematologic malignancy patients including hematopoietic stem cell transplantation (HCT) recipients. However, limited information is available for risk stratification in PIV-infected patients with hematologic malignancy with or without HCT. Patients with hematologic malignancy diagnosed with PIV from January 2009 to December 2018 were retrospectively included in a tertiary care hospital in Seoul, South Korea. Upper respiratory tract infection (URTI) was defined as the detection of PIV in a nasopharyngeal sample with URTI symptoms without new pulmonary infiltrates. Lower respiratory tract infection (LRTI) was defined as detection of PIV in either upper or lower respiratory tract samples with new pulmonary infiltrates, with or without hypoxia. PIV-associated mortality was defined as death with respiratory failure and persistent LRTI within 90 days after diagnosis. The study included 143 adult patients. Of these, 55 (38%) progressed to or initially presented with LRTI. Among these, 22 (40%) died from PIV-associated mortality. An immunodeficiency risk score was developed from associated risk factors using a multivariable Cox regression model. Patients were stratified into low (0-2), moderate (3-5), and high risk (6-8) groups with PIV-associated mortalities of 0%, 9%, and 67%, respectively (p < 0.005, Harrell's C-index = 0.84). PIV infection can result in substantial mortality in patients with hematologic malignancy if it progresses to LRTI. The immunodeficiency risk score presented here may be useful for distinguishing moderate and high risk groups that might benefit from antiviral therapy.

Monosomal karyotype affecting outcomes of allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia in first complete remission.

OBJECTIVES: We evaluated the prognostic impact of MK on postremission outcomes of AML patients receiving allogeneic hematopoietic stem cell transplantation (HSCT) in the first complete remission (CR1). METHODS: We retrospectively analyzed 465 adult patients with AML who had received HSCT in the first CR between 2000 and 2016. RESULTS: In MK + AML, the median leukocyte count was significantly lower (P < .001) and no NPM1 mutation was found (P = .042). Multivariate analysis revealed that MK was the most powerful prognostic factors for OS (hazard ratio [HR], 2.6; P = .001), EFS (HR, 3.8; P < .001), and cumulative incidence of relapse (HR, 6.1; P < .001), compared to any other poor risk factors such as complex karyotype, FLT3-ITD mutations, old age, and higher leukocyte count. The adverse prognostic impact of MK tended to be more prominent in the younger age group (<40 years) (HR, 6.3, P < .001) than in the older age group (≥40 years) (HR, 3.4, P < .001). CONCLUSION: Novel treatment modalities for MK + AML need to be investigated to reduce the risk of relapse after HSCT.

Diagnostic usefulness of differential time to positivity in neutropenic cancer patients with suspected catheter-related candidemia.

Methods for distinguishing catheter-related candidemia (CRC) from non-CRC before catheter removal remain limited. We thus evaluated the diagnostic performance of differential time to positivity (DTP) to diagnose CRC in neutropenic cancer patients with suspected CRC. Of the 35 patients enrolled, 15 (43%) with CRC (six definite and nine probable) and 17 (49%) with non-CRC were finally analyzed. Based on the receiver operating characteristic curve, the optimal cutoff value of DTP for diagnosing CRC was ≥1.45 hours with the sensitivity 80% (95% confidence interval [CI], 51-95) and specificity 100% (95% CI, 80-100), respectively.

Effect of Stem Cell Source and Dose on Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Idiopathic Aplastic Anemia: Data from the Korean Aplastic Anemia Trials.

OBJECTIVE: We aimed to evaluate the effect of stem cell source and dose on the survival of various donor subgroups, such as matched sibling donor (MSDs) and alternative donors (ADs), upon bone marrow (BM) or peripheral blood stem cell (PBSC) infusion in aplastic anemia (AA). METHODS: We retrospectively investigated the effects of stem cell source and dose on allogeneic hematopoietic stem cell transplantation (alloHSCT) in AA. RESULTS: A total of 267 patients were included in this analysis. The BM-treated group showed an association with low incidence of any-grade acute graft versus host disease (GvHD) (p < 0.001). A higher stem cell dose was related with a low incidence of extensive chronic GvHD in MSDs (p = 0.025). Multivariate analysis for overall survival (OS) revealed that only age at alloHSCT <31 years (p = 0.010) and prior platelet transfusion <86 U (p = 0.046) in MSDs and higher stem cell dose (hazard ratio = 2.596, p = 0.045) in ADs were favorable prognostic factors. CONCLUSION: PBSCs could be preferred in AD because high stem cell dose may be easily achieved to improve the OS at the expense of acute GvHD. However, BM stem cells are preferred in MSDs.