Zdeněk Kořístek

Methylation of histones in myeloid leukemias as a potential marker of granulocyte abnormalities

We show that common heterochromatin antigenic protein markers [HP1α, ‐β, ‐γ and mono‐, di‐, and trimethylated histone H3 lysine 9 (H3K9)], although present in human blood progenitor CD34+ cells, differentiated lymphocytes, and monocytes, are absent in neutrophil granulocytes and to large extent, in eosinophils. Monomethylated and in particular, dimethylated H3K9 are present to variable degrees in the granulocytes of chronic myeloid leukemia (CML) patients, without being accompanied by HP1 proteins. In patients with an acute phase of CML and in acute myeloid leukemia patients, strong methylation of H3K9 and all isoforms of HP1 are detected. In chronic forms of CML, no strong correlations among the level of histone methylation, disease progression, and modality of treatment were observed. Histone methylation was found even in “cured” patients without Philadelphia chromosome (Ph) resulting from +(9;22)(q34;q11) BCR/ABL translocation, suggesting an incomplete process of developmentally regulated chromatin remodeling in the granulocytes of these patients. Similarly, reprogramming of leukemia HL‐60 cells to terminal differentiation by retinoic acid does not eliminate H3K9 methylation and the presence of HP1 isoforms from differentiated granulocytes. Thus, our study shows for the first time that histone H3 methylation may be changed dramatically during normal cell differentiation. The residual histone H3 methylation in myeloid leukemia cells suggests an incomplete chromatin condensation that may be linked to the leukemia cell proliferation and may be important for the prognosis of disease treatment and relapse.

Efficacy and safety of peripheral blood stem cell collection in elderly donors; does age interfere?

Elderly patients with hematological malignancies are often reliant on allogeneic transplantations. Older family relatives are increasingly involved in utilization as PBSC donors. We analyzed the mobilization results from 103 donors of age ≥55 years in comparison with 121 younger donors of age <55 years. The median CD34+ count in peripheral blood on day +5 of the mobilization was higher in younger than in older donor group (72.0 vs. 37.0 cells/μL, P < 0.0001). Linear regression showed a negative correlation between the age and CD34+ count in peripheral blood (P < 0.0001) and apheresis product (P < 0.0001). Based on multivariate analysis, the amount of circulating CD34+ cells appeared to be negatively influenced by age (P < 0.001) and positively by the preapheresis WBC count (P < 0.001). The precollection CD34+ (P < 0.0001), PLT (P = 0.0144) counts, and age (P = 0.0392) were confirmed as independent factors determining the collection yield. The side effects of G‐CSF administration were similar in both the groups. Apheresis complications were more frequently recorded in elderly donors (29 vs. 15%, P = 0.0096). Higher age represents a risk factor for poorer mobilization results. A requirement for more than one apheresis in older donors occurs more frequently to obtain the adequate amount of CD34+ cells. Mobilization and collection procedures are associated with acceptable risks and complication rates in elderly donors. J. Clin. Apheresis, 2011.

Granulocyte maturation determines ability to release chromatin NETs and loss of DNA damage response; these properties are absent in immature AML granulocytes.

Terminally-differentiated cells cease to proliferate and acquire specific sets of expressed genes and functions distinguishing them from less differentiated and cancer cells. Mature granulocytes show lobular structure of cell nuclei with highly condensed chromatin in which HP1 proteins are replaced by MNEI. These structural features of chromatin correspond to low level of gene expression and the loss of some important functions as DNA damage repair, shown in this work and, on the other hand, acquisition of a new specific function consisting in the release of chromatin extracellular traps in response to infection by pathogenic microbes. Granulocytic differentiation is incomplete in myeloid leukemia and is manifested by persistence of lower levels of HP1γ and HP1β isoforms. This immaturity is accompanied by acquisition of DDR capacity allowing to these incompletely differentiated multi-lobed neutrophils of AML patients to respond to induction of DSB by γ-irradiation. Immature granulocytes persist frequently in blood of treated AML patients in remission. These granulocytes contrary to mature ones do not release chromatin for NETs after activation with phorbol myristate-12 acetate-13 and do not exert the neutrophil function in immune defence. We suggest therefore the detection of HP1 expression in granulocytes of AML patients as a very sensitive indicator of their maturation and functionality after the treatment. Our results show that the changes in chromatin structure underlie a major transition in functioning of the genome in immature granulocytes. They show further that leukemia stem cells can differentiate ex vivo to mature granulocytes despite carrying the translocation BCR/ABL.

Technique for PBSC harvesting in children of weight under 10 kg

Peripheral blood stem cell (PBSC) harvesting in the smallest children (weight <10 kg) using separators is complicated by specific problems. The volume of the separation set exceeds 25% of the total blood volume and the vascular access is generally not sufficient. Therefore, a simple manual technique for PBSC harvesting was developed. Three children (6–9 kg), with newly diagnosed tumours were scheduled to be treated with three to six sequential courses of high-dose chemotherapy, each followed by PBSC support. PBSC harvests were started after mobilization using cyclophosphamide and G-CSF when the peripheral blood CD34+ cell count exceeded 50/μl. About 50 ml of blood was drawn from a venous catheter, injected into a transfer bag containing ACD-A, and centrifuged. The buffy coat obtained was pooled in a collection bag, remaining plasma and erythrocytes were immediately reinfused and a subsequent cycle started. From three to 13 cycles were performed in 1–3 days and 18.0–32.2 × 106 CD34+cells/kg were collected. We did not detect any bacterial contamination or any notable complications. Fifteen PBSC reinfusions have been performed to date, each with rapid engraftment taking between 7 and 13 days. Patients are in very good PR (18 months from diagnosis) or in CR (6 and 8 months). We can conclude that this procedure is feasible and safe.Bone Marrow Transplantation (2002) 29, 57–61. doi:10.1038/sj.bmt.1703334

Intracoronary Delivery of Bone Marrow Cells to the Acutely Infarcted Myocardium

Objectives: Intracoronary cell transplantation during catheter balloon inflations may be associated with adverse events. We studied the effectiveness of an alternative transplantation technique – intracoronary cell infusion. Methods: Fourteen pigs, which had survived acute myocardial infarction, were randomized into 2 treatment groups and 2 controls. Three days after infarction, 12 pigs underwent allogeneic intracoronary mononuclear bone marrow cell transplantation using either the standard technique (short-term cell injections during repeat balloon inflations, technique A, n = 6) or continuous intracoronary cell infusion without balloon inflations (technique B, n = 6). Implanted cells were stained with fluorescent dye. After transplantation, the pigs were euthanized and myocardial samples were analyzed by fluorescent microscopy. Results: The mean numbers of fluorescently labeled bone marrow cells in the infarction border zone, in the infarction mid-area and in the center of myocardial infarction were 84, 72 and 55 using technique A, and 29, 57 and 46 using technique B, respectively. The mean cell retention in the infarction border zone of 84 cells for technique A and 29 cells for technique B differed significantly (p = 0.034, two-tailed t test). Conclusion: The continuous intracoronary cell infusion technique is a less efficient cell delivery technique as compared with the standard technique using repeat intracoronary balloon inflations.

A Case of a Novel PML/RARA Short Fusion Transcript with Truncated Transcription Variant 2 of the RARA Gene

Acute promyelocytic leukemia (APL) with atypical breakpoints in the promyelocytic leukemia (PML) and retinoic acid receptor-α (RARA) genes represents a rare leukemic event, which occurs preferentially in patients with variant types of the PML/RARA fusion gene. Here we report on a patient with APL with a unique PML/RARA fusion transcript that harbors a short type of this fusion gene, exhibiting unexpected results of standard PCR diagnostics. The detected transcript originates from fusion of PML exon 4 and a truncated form of transcription variant 2 of the RARA gene, with an additional 9 bp insertion. According to our knowledge, this differs from all previously described fusion transcripts.

Cost-effectiveness of hematopoietic stem cell mobilization strategies including plerixafor in multiple myeloma and lymphoma patients

Peripheral blood stem cells (PBSCs) are preferred source of hematopoietic stem cells for autologous transplantation. Mobilization of PBSCs using chemotherapy and/or granulocyte colony‐stimulating factor (G‐CSF) however fails in around 20%. Combining G‐CSF with plerixafor increases the mobilizations success. We compared cost‐effectiveness of following schemes: the use of plerixafor “on demand” (POD) during the first mobilization in all patients with inadequate response, the remobilization with plerixafor following failure of the first standard mobilization (SSP), and the standard (re)mobilization scheme without plerixafor (SSNP). Decision tree models populated with data from a first‐of‐a‐kind patient registry in six Czech centers (n = 93) were built to compare clinical benefits and direct costs from the payers perspective. The success rates and costs for POD, SSP and SSNP mobilizations were; 94.9%,

Treatment of chronic myeloid leukemia with autologous transplantation using peripheral blood stem cells or bone marrow cultured in IL-2 followed by IL-2, GM-CSF, and IFN-alpha administration.

7,197; 94.7%,

Mathematical model of peripheral blood stem cell harvest kinetics

8,049; 84.7%,

Three-, 6-, and 12-month results of autologous transplantation of mononuclear bone marrow cells in patients with acute myocardial infarction

5,991, respectively. The direct cost per successfully treated patient was