Histopathologic Characterization of Vexas Syndrome

Introduction: VEXAS syndrome (vacuoles, E1 ubiquitin ligase, X-linked, autoinflammatory, somatic) is a newly recognized inflammatory disorder caused by somatic mutations in the UBA1 gene. Bone marrows from these patients reveal a range of morphological changes in hematopoietic precursor cells. In this study, we aim to assess the laboratory indices and morphologic spectrum of bone marrow pathology in VEXAS syndrome. Methods: We identified 16 cases of VEXAS syndrome. All cases had confirmed UBA1 mutation. We reviewed bone marrow biopsies corresponding to the date of diagnosis. This study was approved by the Mayo Clinic Institutional Review Board. Results: All patients were male with a median age of 73 years - associated autoimmune disorders included Sweet syndrome, inflammatory arthritis, relapsing polychondritis and granulomatosis with polyangiitis. 14/16 patients had anemia with median hemoglobin of 10.4 (Range: 6.7- 14.1 g/dL). 15/16 had macrocytosis with median MCV 110.4 (Range: 94.8- 123.1 /fL). 5/16 had thrombocytopenia with median platelet count 174 (Range: 20- 500 x10^9/L). 7/16 had leukopenia with median WBC 3.65 (Range: 2.4- 11.6 x10^9/ L). The ESR and CRP medians were 61.0 mm/hr and 81.5 mg/L, respectively. Karyotype was performed in 12 patients of which 11 were normal and the remaining case showed a complex karyotype. An NGS panel targeting the most frequent myeloid disorder associated gene mutations was negative in 10/15 cases. GS for myeloid mutations revealed pathogenic mutations in 5 patients, involving genes TET2 (2/5), DNMT3A (2/5), and TP53 (1/5). Conclusions: Bone marrow findings in VEXAS syndrome, in this series of 16 patients, are individually non-specific, yet when taken altogether in the overtly abnormal cases, are very suggestive when the clinical index of suspicion is high. In such scenarios, the combined clinical and bone marrow findings should prompt discussion and consideration for UBA1 mutation testing given the significant clinical implications for patient management and prognosis. Disclosures Patnaik: StemLine: Research Funding; Kura Oncology: Research Funding. Warrington: Eli Lilly: Research Funding; Kiniksa: Research Funding.

Mutation analysis links angioimmunoblastic T-cell lymphoma to clonal hematopoiesis and smoking

Background:Although advance has been made in understanding the pathogenesis of mature T-cell neoplasms, the initiation and progression of angioimmunoblastic T cell lymphoma (AITL) and peripheral T cell lymphoma, not otherwise specified (PTCL-NOS), remains poorly understood. A subset of AITL/PTCL-NOS patients develop concomitant hematologic neoplasms (CHN), and a biomarker to predict this risk is lacking. Methods:We generated and analyzed the mutation profiles through 537-gene targeted sequencing of the primary tumors and matched bone marrow/peripheral blood samples in 25 patients with AITL and 2 with PTCL-NOS. Results:Clonal hematopoiesis (CH)-associated genomic alterations, found in 70.4% of the AITL/PTCL-NOS patients, were shared among CH and T-cell lymphoma, as well as concomitant myeloid neoplasms or diffuse large B-cell lymphoma (DLBCL) that developed before or after AITL. Aberrant AID/APOBEC activity-associated and tobacco smoking-associated mutational signatures were respectively enriched in the early CH-associated mutations and late non-CH associated mutations during AITL/PTCL-NOS development. Moreover, analysis showed that the presence of CH harboring ≥ 2 pathogenic TET2 variants with ≥ 15% of allele burden conferred higher risk for CHN (P = 0.0006, hazard ratio = 14.01, PPV=88.9%, NPV=92.1%). Conclusion:We provided genetic evidence that AITL/PTCL-NOS, CH, CHN can frequently arise from common mutated hematopoietic precursor clones. Our data also suggests smoking exposure as a potential risk factor for AITL/PTCL-NOS progression. These findings provide insights into the cell origin and etiology of AITL and PTCL-NOS and provide a novel stratification biomarker for CHN risk in AITL patients. Funding:R01 grant (CA194547) from the National Cancer Institute to WT.

HOXA9 promotes MYC-mediated leukemogenesis by maintaining gene expression for multiple anti-apoptotic pathways

HOXA9 is often highly expressed in leukemias. However, its precise roles in leukemogenesis remain elusive. Here, we show that HOXA9 maintains gene expression for multiple anti-apoptotic pathways to promote leukemogenesis. In MLL fusion-mediated leukemia, MLL fusion directly activates the expression of MYC and HOXA9. Combined expression of MYC and HOXA9 induced leukemia, whereas single gene transduction of either did not, indicating a synergy between MYC and HOXA9. HOXA9 sustained expression of the genes implicated in the hematopoietic precursor identity when expressed in hematopoietic precursors, but did not reactivate it once silenced. Among the HOXA9 target genes, BCL2 and SOX4 synergistically induced leukemia with MYC. Not only BCL2, but also SOX4 suppressed apoptosis, indicating that multiple anti-apoptotic pathways underlie cooperative leukemogenesis by HOXA9 and MYC. These results demonstrate that HOXA9 is a crucial transcriptional maintenance factor that promotes MYC-mediated leukemogenesis, potentially explaining why HOXA9 is highly expressed in many leukemias.

A Young Male with a Non-ST Elevation Myocardial Infarction and Polycythemia Vera

Polycythemia Vera (PV) is a clonal myeloproliferative disease characterized by an erythroid dominant trilineage proliferation of hematopoietic precursor cells. Acute coronary syndrome is known to occur in patients with PV. However, there are very rare reported cases of myocardial infarction upon the initial presentation of PV. We present such a case of a 37 years old male, with no known cardiovascular risk factors, who had an initial presentation of NSTEMI treated with drug eluting stent (DES). Later investigations revealed a diagnosis of Polycythemia Vera. Treatment strategies for MI in cases of myeloproliferative disease lacking clear guidance, further studies are needed in this matter.

Hyper-SUMOylation of ERG Is Essential for the Progression of Acute Myeloid Leukemia

Leukemia is a malignant disease of hematopoietic tissue characterized by the differentiation arrest and malignant proliferation of immature hematopoietic precursor cells in bone marrow. ERG (ETS-related gene) is an important member of the E26 transformation-specific (ETS) transcription factor family that plays a crucial role in physiological and pathological processes. However, the role of ERG and its modification in leukemia remains underexplored. In the present study, we stably knocked down or overexpressed ERG in leukemia cells and observed that ERG significantly promotes the proliferation and inhibits the differentiation of AML (acute myeloid leukemia) cells. Further experiments showed that ERG was primarily modified by SUMO2, which was deconjugated by SENP2. PML promotes the SUMOylation of ERG, enhancing its stability. Arsenic trioxide decreased the expression level of ERG, further promoting cell differentiation. Furthermore, the mutation of SUMO sites in ERG inhibited its ability to promote the proliferation and inhibit the differentiation of leukemia cells. Our results demonstrated the crucial role of ERG SUMOylation in the development of AML, providing powerful targeted therapeutic strategies for the clinical treatment of AML.

Toll-like receptor-9 stimulated plasmacytoid dendritic cell precursors suppress autoimmune neuroinflammation in a murine model of multiple sclerosis

Early innate education of hematopoietic progenitors within the bone marrow (BM) stably primes them for either trained immunity or instead immunoregulatory functions. We herein demonstrate that in vivo or in vitro activation within the BM via Toll-like receptor-9 generates a population of plasmacytoid dendritic cell (pDC) precursors (CpG-pre-pDCs) that, unlike pDC precursors isolated from PBS-incubated BM (PBS-pre-pDCs), are endowed with the capacity to halt progression of ongoing experimental autoimmune encephalomyelitis. CpG activation enhances the selective migration of pDC precursors to the inflamed spinal cord, induces their immediate production of TGF-β, and after migration, of enhanced levels of IL-27. CpG-pre-pDC derived TGF-β and IL-27 ensure protection at early and late phases of the disease, respectively. Spinal cords of CpG-pre-pDC-protected recipient mice display enhanced percentages of host-derived pDCs expressing TGF-β as well as an accumulation of IL-10 producing B cells and of CD11c+ CD11b+ dendritic cells. These results reveal that pDC precursors are conferred stable therapeutic properties by early innate activation within the BM. They further extend to the pDC lineage promising perspectives for cell therapy of autoimmune diseases with innate activated hematopoietic precursor cells.

Factors Associated with the Platelet Graft in Hematopoietic Precursor Cell Transplant Patients in a Third Level Hospital in Mexico

Factors associated with the platelet graft in hematopoietic precursor cell transplant patients in a third level hospital in Mexico Introduction The success of TCPH is affected by various factors such as graft versus host disease (GVHD), relapse, treatment-related toxicity, and infection, leading to increased morbidity and mortality. Thrombocytopenia is almost universal in the pre-graft period in patients sometimes on TCPH, delayed platelet recovery beyond the expected time occurs in 5% to 37% of patients sometimes on TCPH. Various studies have described a relationship between platelet graft delay and CD34 + cell dose, pre-transplant disease status, source of the graft, blood group, and even the development of platelet refractoriness. Male receptor gender and elevated serum hepcidin level have also been associated as risk factors for delayed platelet graft. Aims To assess the factors associated with late platelet grafting in the post-transplant patient of hematopoietic precursor cells. Methods Retrospective, cross-sectional, observational and descriptive study. From January 2018 to December 2019. Results 101 patients were included, 59.4% men and 40.6% women. The mean age was 37 years. Patients diagnosed with MM were 24.8%, ALL 22.8%, NHL 19.8%, HL 15.8%, AML 14.9%, CML 1%. 73.3% of the patients had a CR prior to transplantation and 26.7% had a PR. BUCY was used as a conditioning scheme in 27.7%, PEAM 27.7%, FLUBUCY 16.8%, BORMEL 11.9%, BUMEL 9.9%. 55.4% of the patients underwent autologous transplantation and 44.6% underwent allogeneic. During the peritransplantation period, 32.7% had some type of infection, 21.8% developed GVHD, and 12.9% had a relapse of the disease. Of the 101 patients, 85.1% were alive at the time of this study; 3 of these patients did not achieve a platelet graft, 2 of them required a thrombopoietic receptor agonist, 2 had a diagnosis of ALL and one had MM, the 3 patients died before the +100 day due to infectious complications. The mean platelet apheresis transfusion was 1.80. The mean recovery time for neutrophils was 11 days and for platelets 13 days. The mean follow-up was 25 months. The overall one-year survival is 70% in allogeneic post-transplant patients and 95% in autologous post-transplant patients Of the factors evaluated using the KM method to relate them to overall survival, statistical significance was found: relapse (p = 0.0001), GVHD (p = 0.002) and more than 5 x 106CD34 infused (p = 0.047). The recovery time for the platelet and neutrophil graft was not statistically significant, p=0.288 and p = 0.421 respectively. GVHD was the only factor associated with relapse-free survival. When performing a bivariate analysis, the factors with statistical significance (p= <0.05) related to the platelet graft were: allogeneic transplantation, the amount of CD34 infused, infections and GVHD. Discussion The mean time for neutrophil and platelet grafting was 11 and 13 days, respectively. According to the bivariate analysis performed, allogeneic transplantation confers 6.7 times more risk for the platelet graft to be greater than 13 days p= 0.0001. Begeman et al. have reported that there is an inverse relationship between the amount of CD34 infused and the time of platelet grafting. This observation was not reproducible in our population since we found that an amount greater than 5 x 106 CD34 conferred a 4.4-fold risk for the platelet graft to be greater than 13 days, with a p= 0.0001. This could suggest that it is probable that an amount greater than 5 x 106 could have an opposite effect and prolong the grafting time; this will have to be taken with reserve since in our multivariate a significant result was not confirmed. Overall survival and relapse-free survival were not affected by neutrophil or platelet graft time as described in some studies; probably due to the size of our sample and that in other series the follow-up time has been comparable. The median of relapse-free survival was reached at 5 months and it should be noted that relapse was the only factor that had a negative impact on the survival of our population, and was observed only in patients undergoing allogeneic transplantation; therefore, those patients who present a relapse of the disease have a poor prognosis, whose median was reached at 25 months, so perhaps it would be worthwhile to search for available rescue therapies in these patients. Disclosures No relevant conflicts of interest to declare.

HOXA9 promotes MYC-mediated leukemogenesis by maintaining gene expression for multiple anti-apoptotic pathways

HOXA9 is often highly expressed in leukemias. However, its precise roles in leukemogenesis remain elusive. Here, we show that HOXA9 maintains gene expression for multiple anti-apoptotic pathways to promote leukemogenesis. In MLL-rearranged leukemia, MLL fusion directly activates the expression of MYC and HOXA9. Combined expression of MYC and HOXA9 induced leukemia, whereas single gene transduction of either did not, indicating a synergy between MYC and HOXA9. HOXA9 sustained expression of the genes implicated to the hematopoietic precursor identity when expressed in hematopoietic precursors, but did not reactivate it once silenced. Among the HOXA9 target genes, BCL2 and SOX4 synergistically induced leukemia with MYC. Not only BCL2, but also SOX4 suppressed apoptosis, indicating that multiple anti-apoptotic pathways underlie cooperative leukemogenesis by HOXA9 and MYC. These results demonstrate that HOXA9 is a key transcriptional maintenance factor which promotes MYC-mediated leukemogenesis, potentially explaining why HOXA9 is highly expressed in many leukemias.