Photodepletion with 2-Se-Cl prevents lethal graft-versus-host disease while preserving antitumor immunity.

Acute graft-versus-host-disease (GVHD), limits the use of hematopoietic cell transplant (HCT) to treat a variety of malignancies. Any new therapeutic approach must satisfy three requirements: 1) Prevent GVHD, 2) Maintain anti-pathogen immunity, and 3) Maintain anti-tumor immunity. In prior studies we have shown that the selective photosensitizer 2-Se-Cl eliminates highly alloreactive lymphocytes from the graft prior to HCT preventing GVHD and that antiviral immune responses were preserved following incubation with 2-Se-Cl. In this report, we investigated whether 2-Se-Cl treatment preserves antitumor immunity, and then used high dimensional flow cytometry to identify the determinants of successful immune reconstitution. Donor C57BL/6 splenocytes were cocultured for 4 days with irradiated BALB/c splenocytes and then exposed to 2-Se-Cl. Photodepletion (PD)-treated splenocytes were then infused into lethally irradiated BALB/c mice inoculated with A20 leukemia/lymphoma cells. Recipient mice that received PD-treated splenocytes survived > 100 days without evidence of GVHD or leukemia. In contrast, mice that did not receive PD-treated cells at time of HCT died of leukemia progression. Multiparameter flow cytometry of cytokines and surface markers on peripheral blood samples 15 days after HCT demonstrated unique patterns of immune reconstitution. We found that before clinical disease onset GVHD was marked by functionally exhausted T cells, while tumor clearance and long-term survival were associated with an expansion of polyfunctional T cells, monocytes, and DCs early after transplantation. Taken together these results demonstrate that 2-Se-Cl photodepletion is a new treatment that can facilitate HCT by preventing GVHD while preserving antiviral and anti-tumor immunity

TREX1 D18N mice fail to process erythroblast DNA resulting in inflammation and dysfunctional erythropoiesis

Anaemia is commonly observed in chronic inflammatory conditions, including systemic lupus erythematosus (SLE), where ∼50% of patients display clinical signs of anaemia. Mutation at the aspartate residue 18 of the three prime repair exonuclease 1 (TREX1) gene causes a monogenic form of cutaneous lupus in humans and the genetically precise TREX1 D18N mice recapitulate a lupus-like disease. TREX1 degrades single- and double-stranded DNA (dsDNA), and the link between failed DNA degradation by nucleases, including nucleoside-diphosphate kinases (NM23H1/H2) and Deoxyribonuclease II (DNase II), and anaemia prompted our studies to investigate whether TREX1 dysfunction contributes to anaemia. Utilizing the TREX1 D18N mice we demonstrate that (1) TREX1 mutant mice develop normocytic normochromic anaemia and (2) TREX1 exonuclease participates in the degradation of DNA originating from erythroblast nuclei during definitive erythropoiesis. Gene expression, hematocrit, hemoglobin, immunohistochemistry (IHC) and flow cytometry were used to quantify dysfunctional erythropoiesis. An altered response to induced anaemia in the TREX1 D18N mice was determined through IHC, flow cytometry, and interferon-stimulated gene (ISG) expression analysis of the liver, spleen and erythroblastic islands (EBIs). IHC, flow cytometry, and ISG expression studies were performed in vitro to determine the role of TREX1 in the degradation of erythroblast DNA within EBIs. The TREX1 D18N mice exhibit altered erythropoiesis including a 20% reduction in hematocrit, 10–20 fold increased erythropoietic gene expression levels in the spleen and phenotypic signs of normocytic normochromic anaemia. Anaemia in TREX1 D18N mice is accompanied by increased erythropoietin (Epo), normal hepcidin levels and the TREX1 D18N mice display an inappropriate response to anaemic challenge. Enhanced ISG expression results from failed processing and subsequent sensing of undegraded erythroblast DNA in EBIs. TREX1 participates in the degradation of erythroblast DNA in the EBI and TREX1 D18N mice exhibit a normocytic normochromic anaemia

Survival and Predictors of Outcome in Acute Leukemia Patients Admitted to the Intensive Care Unit

Abstract Background: Patients with acute leukemia fare poorly when admitted to intensive care units (ICUs). Predictors of outcome and rates of successful discharge have not been defined in the United States. Methods: This is a retrospective analysis of 78 acute leukemia patients admitted to the medical ICU from 2001–2004. Patients were identified by ICD-9 codes and a sudden increase in daily hospital charges (indicating a direct ICU admission or transfer to the ICU from a medical floor). The primary endpoints were improvement and subsequent ICU discharge with continued aggressive leukemia management and survival to 2 months following hospital discharge. Secondary endpoints included 6 and 12 month survival. Univariate and multivariate logistic regression analyses were performed to identify factors predicting outcome. Results: Sixty-five patients were diagnosed with AML and 13 with ALL. Seven patients had good-risk cytogenetics, 32 intermediate, 30 poor and 9 unknown, as defined by CALGB 8461. Fever or infection (37.2%) was the leading cause of hospital admission. The mean age was 53 years, 85% were Caucasian and 51% were female. The median white blood cell (WBC) count was 6.9K. On average, patients were transferred to the ICU on hospital day 13. Of the 69 patients who received chemotherapy, 29 (42%) were in the induction phase and 40 (58%) in the consolidation or relapsed/refractory phase, with a mean chemotherapy day of 15. The most common reason for transfer to the ICU was respiratory compromise (68%) with sepsis (56%) second. Most patients transferred to the ICU had either 1 (47%) or 2 (45%) reasons for transfer. While in the ICU 57 patients required mechanical ventilation with 21 eventually extubated (19 improved; 2 withdrew care). Hemodynamic support (pressors) was used in 41 patients. The mean length of stay in the ICU was 7 days. The mean APACHE II score was 23 ± 7, predicting a mortality of 40%. Overall, 22 patients (28%) improved and 49 (63%) died in the ICU. Seven patients (9%) died after transfer out of the ICU. Two month survival following hospital discharge was 21%. At 6 and 12 months, 13% and 12% were alive, respectively. In univariate analysis, patients with lower APACHE II scores were more likely to improve in the ICU (p=0.002) and to live 2 months post-discharge (p=0.004) than those with higher scores; these findings remained significant in multivariate analysis. In univariate analysis, patients requiring hemodynamic support had lower 6 and 12 month survival than patients not requiring support (p=0.017 and 0.025); these findings remained significant in multivariate analysis (p=0.007 and 0.013). Multivariate analysis also showed that patients with poor risk cytogenetics had lower 6 and 12 month survival than patients with good or intermediate risk cytogenetics (p=0.026 and 0.05). Neither age, WBC, or treatment phase predicted outcome. Conclusion: Higher APACHE II score, use of pressors and adverse cytogenetics predicted for worse outcome. Increased age and presenting WBC did not. One out of five patients survived an ICU admission to be discharged from the hospital. Aggressive medical management is appropriate for patients with acute leukemia and should not be withheld even in patients with advanced age