Consequently, RBPs that regulate this event directly contribute to healthy and aberrant hematopoiesis. We modeled RUNX1 APA using a split GFP minigene reporter and confirmed the sensitivity of our model to detect changes in RNA processing. We used this reporter in a clustered regularly interspaced short palindromic repeats (CRISPR) screen consisting of single guide RNAs exclusively targeting RBPs and uncovered HNRNPA1 and KHDRBS1 as antagonistic regulators of RUNX1a isoform generation.  https://www.selleckchem.com/products/ldc203974-imt1b.html  Overall, our study provides mechanistic insight into the posttranscriptional regulation of a key hematopoietic transcription factor and identifies RBPs that may have widespread and important functions in hematopoiesis.The high-specific-activity factor IX (FIX) variant Padua (R338L) is the most promising transgene for hemophilia B (HB) gene therapy. Although R338 is strongly conserved in mammalian evolution, amino acid substitutions at this position are underrepresented in HB databases. We therefore undertook a complete 20 amino acid scan and determined the specific activity of human (h) and canine (c) FIX variants with every amino acid substituted at position 338. Notably, we observe that hFIX-R338L is the most active variant and cFIX-R338L is sevenfold higher than wild-type (WT) cFIX. This is consistent with the previous identification of hFIX-R338L as a cause of a rare X-linked thrombophilia risk factor. Moreover, WT hFIX and cFIX are some of the least active variants. We confirmed the increased specific activity relative to FIX-WT in vivo of a new variant, cFIX-R338I, after gene therapy in an HB dog. Last, we screened 232 pediatric subjects with thromboembolic disease without identifying F9 R338 variants. Together these observations suggest a surprising evolutionary pressure to limit FIX activity with WT FIX rather than maximize FIX activity.Acute graft-versus-host disease (aGVHD) has various risk factors and outcomes. We defined distinct aGVHD treatment response groups based on response to first-line corticosteroids steroid sensitive (SS), steroid resistant (SR), and the rarely studied steroid dependent (SD) aGVHD. In 1143 consecutive adult and pediatric allogeneic hematopoietic cell transplant recipients, 385 (34%) developed aGVHD, with 10% having SS aGVHD, 9% SD aGVHD, and 14% SR aGVHD. The only factor significantly associated with SD in comparison with SS was older age (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.4-11.3, when comparing 18- to 60-year-olds with less then 18-year-olds). Factors significantly associated with SR in comparison with SS were unrelated donor (OR, 3.0; 95% CI, 1.2-7.4) and Minnesota high-risk aGVHD (OR, 2.4; 95% CI, 1.3-4.6). SR aGVHD was independently associated with higher risk for 2-year overall mortality (hazards ratio [HR], 1.8; 95% CI, 1.2-2.8) and nonrelapse mortality (NRM; HR, 2.1; 95% CI, 1.2-3.9). SS and SD GVHD groups had similar overall survival and NRM. The cumulative incidence of chronic GVHD was highest in the SD group, followed by the SR and SS groups (46%, 41%, and 29%, respectively). SD and SS GVHD had similar prognoses, both markedly better than those of the SR groups.We report on the outcome of 24 patients with Fanconi anemia (FA) lacking an HLA matched related or unrelated donor, given an HLA-haploidentical T-cell receptor αβ (TCRαβ+) and CD19+ cell-depleted hematopoietic stem cell transplantation (HSCT) in the context of a prospective, single-center phase 2 trial. Sustained primary engraftment was achieved in 22 (91.6%) of 24 patients, with median time to neutrophil recovery of 12 days (range, 9-15 days) and platelet recovery of 10 days (range, 7-14 days). Cumulative incidences of grade 1 to 2 acute graft-versus-host disease (GVHD) and chronic GVHD were 17.4% (95% confidence interval [CI], 5.5%-35.5%) and 5.5% (95% CI, 0.8%-33.4%), respectively. The conditioning regimen, which included fludarabine, low-dose cyclophosphamide and, in most patients, single-dose irradiation was well tolerated; no fatal transplant-related toxicity was observed. With a median follow-up of 5.2 years (range, 0.3-8.7 years), the overall and event-free survival probabilities were 100% and 86.3% (95% CI, 62.8%-95.4%), respectively (2 graft failures and 1 case of poor graft function were considered as events). The 2 patients who experienced primary graft failure underwent a subsequent successful HSCT from the other parent. This is the first report of FA patients given TCRαβ+/CD19+-depleted haplo-HSCT in the context of a prospective trial, and the largest series of T-cell-depleted haplo-HSCT in FA reported to date. This trial was registered at www.clinicaltrials.gov as #NCT01810120.Population-based studies that contain detailed clinical data on patients with myelodysplastic syndrome (MDS) are scarce. This study focused on the real-world overall survival (OS) of MDS patients in association with comorbidities, specifically malignancies. An observational population-based study using the HemoBase registry was performed, including all patients with MDS diagnosed between 2005 and 2017 in Friesland, a Dutch province. Detailed information about diagnosis, patient characteristics, previous treatment of malignancies, and comorbidities according to the Charlson Comorbidity Index (CCI) was collected from electronic health records. Patients were followed up until June 2019. Kaplan-Meier plots and Cox regression analyses were used to study survival differences. In the 291 patients diagnosed with MDS, the median OS was 25.3 months (95% confidence interval [CI], 20.3-30.2). OS was significantly better for patients with CCI score less then 4, age less then 65 years, female sex, and low-risk MDS. Fifty-seven patients (20%) had encountered a prior malignancy (excluding nonmelanoma skin cancer), and a majority (38 patients; 67%) were therapy related. Both therapy-related and secondary MDSs were associated with worse OS (hazard ratio, 1.51; 95% CI, 1.02-2.23 and 1.58; 95% CI, 0.95-2.65, respectively), as compared with de novo MDS patients (P = .04). Patients in remission at time of MDS diagnosis had a similar median OS compared with patients with de novo MDS (25.5 vs 28.3 months). This population-based study involving all newly diagnosed MDS patients over a 13-year period in Friesland showed that multiple comorbidities, including previous malignancies, are associated with shorter OS. OS was not related to the use of radiotherapy or chemotherapy.