Exploiting the Role of Hypoxia-Inducible Factor 1 and Pseudohypoxia in the Myelodysplastic Syndrome Pathophysiology.

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem (HSCs) and/or progenitor cells disorders. The established dependence of MDS progenitors on the hypoxic bone marrow (BM) microenvironment turned scientific interests to the transcription factor hypoxia-inducible factor 1 (HIF-1). HIF-1 facilitates quiescence maintenance and regulates differentiation by manipulating HSCs metabolism, being thus an appealing research target. Therefore, we examine the aberrant HIF-1 stabilization in BMs from MDS patients and controls (CTRLs). Using a nitroimidazole-indocyanine conjugate, we show that HIF-1 aberrant expression and transcription activity is oxygen independent, establishing the phenomenon of pseudohypoxia in MDS BM. Next, we examine mitochondrial quality and quantity along with levels of autophagy in the differentiating myeloid lineage isolated from fresh BM MDS and CTRL aspirates given that both phenomena are HIF-1 dependent. We show that the mitophagy of abnormal mitochondria and autophagic death are prominently featured in the MDS myeloid lineage, their severity increasing with intra-BM blast counts. Finally, we use in vitro cultured CD34+ HSCs isolated from fresh human BM aspirates to manipulate HIF-1 expression and examine its potential as a therapeutic target. We find that despite being cultured under 21% FiO2, HIF-1 remained aberrantly stable in all MDS cultures. Inhibition of the HIF-1α subunit had a variable beneficial effect in all <5%-intra-BM blasts-MDS, while it had no effect in CTRLs or in ≥5%-intra-BM blasts-MDS that uniformly died within 3 days of culture. We conclude that HIF-1 and pseudohypoxia are prominently featured in MDS pathobiology, and their manipulation has some potential in the therapeutics of benign MDS.

Bone metabolism markers and angiogenic cytokines as regulators of human hematopoietic stem cell mobilization.

Hematopoietic stem cell (HSC) mobilization involves cleavage of ligands between HSC and niche components. However, there are scarce data regarding the role of bone cells in human HSC mobilization. We studied biochemical markers of bone metabolism and angiogenic cytokines during HSC mobilization in 46 patients' sera with lymphoma and multiple myeloma, by ELISA. Significant changes between pre-mobilization and collection samples were found: (1) Bone alkaline phosphatase (BALP) increased, indicating augmentation of bone formation; (2) Receptor activator of Nf-κB ligand/osteoprotegerin ratio (RANKL/OPG) increased, showing osteoclastic differentiation and survival; however, there was no evidence of increased osteoclastic activity; and (3) Angiopoietin-1/Angiopoietin-2 ratio (ANGP-1/ANGP-2) decreased, consistent with vessel destabilization. Poor mobilizers had significantly higher carboxy-terminal telopeptide of collagen type I (CTX) and lower ANGP-1 at pre-mobilization samples, compared to good ones. CTX, amino-terminal telopeptide of collagen type I (NTX) and ANGP-1 pre-mobilization levels correlated significantly with circulating CD34+ peak cell counts. Our results indicate that bone formation and vessel destabilization are the two major events during human HSC mobilization. Osteoblasts seem to be the orchestrating cells, while osteoclasts are stimulated but not fully active. Moreover, ANGP-1, CTX and NTX may serve as predictors of poor mobilization.

Richter's transformation as leptomeningeal infiltration in a chronic lymphocytic leukemia patient receiving venetoclax. Could blood-brain barrier be a disease "sanctuary" during venetoclax treatment?

Our unique case of Richter's Transformation presenting as leptomeningial infiltration in a CLL patient receiving venetoclax raises questions on whether the drug penetrates the blood-brain barrier and at what extend, especially in reduced doses given for drug-drug interactions.

Endothelial progenitor cells and peripheral neuropathy in subjects with type 2 diabetes mellitus.

AIMS: To examine for differences in circulating progenitor cells (CPCs) and endothelial progenitor cells (EPCs) in patients with and without diabetic peripheral neuropathy (DPN). METHODS: A total of 105 participants were included: 50 patients with type 2 diabetes (T2DM) and DPN, 30 patients with T2DM without DPN and 25 healthy individuals. CPCs and 6 different EPCs phenotypes were assessed with flow cytometry. We also measured plasma levels of vascular endothelial growth factor (VEGF), stromal cell-derived factor 1 (SDF-1), vascular cell adhesion protein-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM) and tumor necrosis factor a (TNFa). RESULTS: No difference was observed in the number of CPCs among the 3 groups. Patients with DPN had higher numbers of all 6 EPCs phenotypes when compared with patients without DPN and higher number of 5 EPCs phenotypes when compared with healthy individuals. Plasma VEFG, VCAM-1, ICAM-1 and TNFa levels did not differ among the 3 groups. Patients with DPN had lower SDF-1 levels in comparison with healthy individuals. CONCLUSION: Circulating EPCs are increased while SDF-1 levels are decreased in the presence of DPN. Our findings suggest that DPN may be associated with impaired trafficking of EPCs and impaired EPCs homing to the injured endothelium.

Bioenergetic Profiling of the Differentiating Human MDS Myeloid Lineage with Low and High Bone Marrow Blast Counts.

Myelodysplastic syndromes (MDS) encompass a very heterogeneous group of clonal hematopoietic stem cell differentiation disorders with malignant potential and an elusive pathobiology. Given the central role of metabolism in effective differentiation, we performed an untargeted metabolomic analysis of differentiating myeloid lineage cells from MDS bone marrow aspirates that exhibited <5% (G1) or ≥5% (G2) blasts, in order to delineate its role in MDS severity and malignant potential. Bone marrow aspirates were collected from 14 previously untreated MDS patients (G1, n = 10 and G2, n = 4) and age matched controls (n = 5). Following myeloid lineage cell isolation, untargeted mass spectrometry-based metabolomics analysis was performed. Data were processed and analyzed using Metabokit. Enrichment analysis was performed using Metaboanalyst v4 employing pathway-associated metabolite sets. We established a bioenergetic profile coordinated by the Warburg phenomenon in both groups, but with a massively different outcome that mainly depended upon its group mitochondrial function and redox state. G1 cells are overwhelmed by glycolytic intermediate accumulation due to failing mitochondria, while the functional electron transport chain and improved redox in G2 compensate for Warburg disruption. Both metabolomes reveal the production and abundance of epigenetic modifiers. G1 and G2 metabolomes differ and eventually determine the MDS clinical phenotype, as well as the potential for malignant transformation.

Diagnostic role of cytology in serous effusions of patients with hematologic malignancies.

BACKGROUND: We investigated serous effusions occurring during the course of an already known hematologic neoplasia or as a first manifestation of it. We correlated cytology results with flow cytometry results, when available. In the absence of flow cytometry, our correlation was based on clinical follow up information obtained retrospectively. We evaluated our results in relation to the data of the literature and we considered some new suggestions for the improvement of cytology service. METHODS: Serous effusions in hematologic patients were retrieved from the files of the Department of Cytology, Laiko Hospital, for a period of 2 years. All patients had enrolled either a previous hematologic history, or a suspicious clinical and imaging status. Seventy-three serous effusions were included. Cytology reports consisting of morphology and immunocytochemistry assessment were correlated to flow cytometry results and, occasionally, to clinical follow-up. RESULTS: In the group of patients with previous history, sensitivity was 82.76%, positive predictive value was 100%, specificity 100%, and negative predictive value was 58.33%. In the group of patients without previous history, sensitivity and positive predictive value were both 91%, whereas specificity and negative predictive value could not be estimated. CONCLUSION: We provide evidence that the diagnostic accuracy of cytology with the adjunct of immunocytochemistry is high compared to flow cytometry for detecting hematologic malignancies. In order to improve clinical performance, it is suggested that a cytology triage of serous effusions in all patients with hematologic malignancy must be implemented.

An Adult Patient with Early Pre-B Acute Lymphoblastic Leukemia with t(12;17)(p13;q21)/ZNF384-TAF15.

This is a case report of a 46-year-old man diagnosed with early pre-B acute lymphoblastic leukemia (ALL), bearing the translocation t(12;17)(p13;q21) as the sole chromosomal abnormality. This is a rare chromosomal abnormality that has been reported in approximately 25 cases worldwide. FISH analysis revealed a rearrangement of ZNF384 (12p13) and TAF15 (17q12) genes, which is usually associated with a pre-B ALL phenotype with co-expression of the myeloid markers CD13 and/or CD33. ZNF384 encodes a zinc finger protein, which acts as a transcription factor, regulating the expression of several matrix metalloproteinases and TAF15 belongs to the FET (FUS, EWS, and TAF15) family, consisting of RNA and DNA-binding proteins. Unlike most of the cases where CD10 expression was absent or weak, in our case CD10 was highly expressed. The prognostic significance of ZNF384/TAF15 fusion is not very clear since several reports support a generally good prognosis, while others support a poor clinical outcome. Our patient was treated with the German multicenter ALL (GMALL) protocol for B-ALL, but experienced a fulminant gram-negative sepsis and eventually died during induction therapy.

Prognostic significance of signal transducer and activator of transcription 5 and 5b expression in Epstein-Barr virus-positive patients with chronic lymphocytic leukemia.

Signal transducer and activator of transcription (STAT) proteins have been intensively studied in hematologic malignancies, and the efficacy of agents against STATs in lymphomas is already under research. We investigated the expression of total STAT5 and STAT5b in peripheral blood samples of patients with chronic lymphocytic leukemia (CLL) in correlation with the presence of Epstein-Barr Virus (EBV) and its major oncoprotein (latent membrane protein 1, LMP1). The EBV load was measured in the peripheral blood by real-time PCR for the BXLF1 gene and the levels of LMP1 by PCR and ELISA. Western blotting was performed for total STAT5 and STAT5b in protein extracts. STAT5b was only expressed in patients (not in healthy subjects) and STAT5 but particularly STAT5b expression was correlated with the presence of the virus (77.3% vs. 51.2%, P = 0.006 for STAT5b) and to the expression of LMP1 (58.3% vs. 21.6%, P = 0.011 for STAT5b). Moreover, the expression of STAT5b and the presence of EBV and LMP1 were strongly negatively correlated with the overall survival of the patients (log-rank test P = 0.011, 0.015, 0.006, respectively). Double positive (for EBV and STAT5b) patients had the lowest overall survival (log-rank test P = 0.013). This is the first report of a survival disadvantage of EBV+ patients with CLL, and the first time that STAT5b expression is correlated with survival. The correlation of STAT5 expression with the presence of the virus, along with our survival correlations defines a subgroup of patients with CLL that may benefit from anti-STAT agents.

5-Azacytidine in the Treatment of Intermediate-2 and High-risk Myelodysplastic Syndromes and Acute Myeloid Leukemia. A Five-year Experience with 44 Consecutive Patients.

BACKGROUND/AIM: The hypomethylating agent 5-azacytidine has been the standard-of-care for patients with higher-risk myelodysplastic syndrome (MDS) during the past few years. Its efficacy has been proven in large clinical trials, and its safety has been shown to be superior to that of conventional treatments. PATIENTS AND METHODS: We conducted a retrospective study on the efficacy and safety of 5-azacytidine in 44 consecutive patients with MDS and acute myeloid leukemia treated with 5-azacytidine during a 63-month period. We recorded the clinical and laboratory characteristics of the patients and we analyzed the response to treatment, overall survival and adverse events during treatment. RESULTS: The median overall survival was 13 months, while serious adverse events consisted mostly of neutropenic infections. CONCLUSION: We reached two possibly valuable conclusions: Younger patients (<73 years), as well as patients receiving treatment at longer than 28-day intervals had a significantly higher overall survival.

Cytomegalovirus meningoencephalitis after rituximab treatment for primary central nervous system lymphoma.

The efficacy and safety of rituximab against B-cell lymphomas is well established. However, there has been an increased incidence of infectious complications after rituximab treatment, mostly hepatitis B reactivation and progressive multifocal leukoencephalopathy. This is the case of a 67-year-old patient with primary central nervous system lymphoma, who developed cytomegalovirus meningoencephalitis after receiving high-dose chemotherapy and rituximab. As there was no evidence of lymphoma relapse or additional immunosuppression, besides his previous treatment, an association between rituximab and cytomegalovirus meningoencephalitis cannot be ruled out.

Adult T-cell leukemia/lymphoma (ATLL): report of two fully documented Hellenic patients.

ATLL is etiologically associated with HTLV-I retrovirus. A population of 10 to 20 million worldwide is estimated to be infected by the virus, but only 1-4% develop ATLL during a 70-year lifespan. The latency period is more than 30 years. The aim of this study was to report two cases of ATLL in Greek patients with the concomitant study of their family members. A 55-year-old woman and a 59-year-old man presented with leucocytosis and lymphocytosis. Both were asymptomatic and physical examination was unremarkable except for minimal lymphadenopathy in the second patient. In both patients blood smears showed small-to-medium-sized, multilobulated lymphocytes, with different degrees of nuclear irregularity. Immunophenotypic study was as follows: CD2 + (97%), CD3 + (95%), CD5 + (95%), CD3/CD4 + (93%), CD3/CD25 + (84%), CD7 -/CD4 + (89%) CD2 + /HLA-DR + (53%), TCRabeta + (96%) and CD7-(7%). Bone marrow biopsy revealed a normal cellularity with dyserythropoiesis and scattered small lymphocytes (CD4 + on immunostaining) Serum HTLV I and II antibodies were positive. T-cell receptor gamma-chain rearrangement was positive in blood lymphocytes by PCR. Cytogenetic analysis showed complex karyotypic abnormalities. DNA analysis by PCR demonstrated the integration of the HTLV-I DNA in the DNA of the neoplastic T cells. Both patients rapidly developed acute type ATLL. In the first patient multiple subcutaneous nodules on the palmar surface of both hands were also observed. She received deoxycoformycin, which was stopped because of autoimmune hemolytic anemia. Corticosteroid treatment was initiated, with gradual improvement. She suffered from recurrent opportunistic infections. She is currently under interferon and zidovudine therapy with stable blood parameters. Chemotherapy was administered to the other patient with > 50% initial response. Both patients' families were tested for serum anti HTLV-I antibodies and their mates were found to be positive; they also had detectable viral DNA by PCR analysis while asymptomatic, with no abnormal clinical findings and normal white blood cell count and morphology. In conclusion, the two aforementioned patients are the first fully documented ATLL patients described in Greece. Investigation for HTLV-I antibodies should be mandatory in all patients with T-cell lymphoproliferative disorders.

Apoptotic and proliferative characteristics of proliferation centers in lymph node sections of patients with chronic lymphocytic leukemia.

We have analyzed the immunohistochemical expression of a wide range of molecules along with the proliferation rate separately in the proliferation centers (PCs) and in the rest of the tumor area, in lymph node or spleen sections of patients with chronic lymphocytic leukemia (CLL). Fas, FasL and c-FLIP were observed both within and outside the PCs in all cases. However, only the difference in FasL expression between the PCs and the non-PC areas attained statistical significance. Median survivin expression in the PCs was higher compared to the non-PC areas. Cleaved caspase 3 was expressed at very low levels both within and outside PCs, while BCL-2 protein was expressed at high levels in all cases in both tumor compartments. Multivariate analysis demonstrated that concurrent overexpression of Fas/FasL/c-FLIP in the PCs was correlated with worse outcome for progression-free survival as well as for overall survival.