Marta Robak

Polymorphism of CD44 Influences the Efficacy of CD34+ Cells Mobilization in Patients with Hematological Malignancies

In the last decade, peripheral blood was the main source of hematopoietic stem cells (HSC) for autologous and allogeneic transplantation. The exact mechanisms of HSC mobilization are still not clear and the efficacy of the procedure is hardly predictable. Ligand-receptor interactions of adhesion molecules, such as SDF1/CXCR4, VLA4/VCAM-1, or CD44/osteopontin, play an important role in homing of HSC in the hematopoietic niche. There is some evidence that disruption of the ligand-receptor complex leads to the egress of HSCs to the peripheral blood. The aim of the present study was the evaluation of constitutive polymorphism of genes encoding cytokines and receptors present in the HSC niche and their impact on the efficacy of mobilization of HSCs in patients with hematological malignancies. We enrolled 110 patients (60 females and 50 males) in the study. The median age of the patients was 55 (range, 22 to 69) years. The group consisted of patients with multiple myeloma (n = 74), non-Hodgkin lymphoma (n = 19), Hodgkin lymphoma (n = 15), or acute myeloid leukemia (n = 2). The mobilization procedures comprised chemotherapy and subsequent granulocyte-colony stimulating factor (G-CSF) at a dose of 10 μg/kg daily. The poor mobilizers group was defined according to Italian National Bone Marrow Transplant Registry criteria: patients with peak CD34(+) in the peripheral blood < 20/μL or total yield < 2 × 10(6) CD34(+) cells/kg body weight in maximum 3 aphereses. Genotyping was performed using standard PCR-based assays. The group of patients (N = 108) who achieved minimal threshold for collections (CD34(+) at least 10/μL) proceeded to apheresis. The median total yield of CD34(+) in this group was 5.6 × 10(6) cells/kg body weight, whereas the median number of cells collected during the first apheresis was 3.3 × 10(6) cells/kg body weight. Median number of days of G-CSF treatment before first apheresis was 10. Fifteen patients fulfilled the criteria for poor mobilizer. The group of poor mobilizers had higher frequency of TT genotype in rs13347 (CD44) gene (CC+ CT versus TT P = .047). Patients homozygous for T allele had a lower total yield of CD34(+) cells/kg body weight than the group with allele C (median, 3.7 × 10(6)/kg versus 5.8 × 10(6)/kg; P = .019) and a lower number of CD34(+) cells gathered during first apheresis (.95 × 10(6)/kg versus 3.3 × 10(6)/kg, P = .04). Multivariate logistic regression analysis revealed that the CD44 TT genotype was the only factor associated with 5-fold higher risk of poor mobilization (P = .037). Polymorphic variants of CXCR4 and VCAM-1 did not significantly influence the efficacy of HSCs mobilization in our group of patients. In conclusion, our results indicate that among investigated single nucleotide polymorphisms (SNPs), only CD44 rs13347 has an impact on the efficacy of HSCs mobilization in patients with hematologic malignancies. CD44 SNPs analysis may be helpful for predicting the poor mobilizers population who may benefit from newer modalities using adhesion molecules inhibitors.

Effects of Rivaroxaban Therapy on ROTEM Coagulation Parameters in Patients with Venous Thromboembolism

BACKGROUND Rivaroxaban (Xarelto) does not require routine coagulation monitoring; however, in certain clinical situations (overdose, drug accumulation, urgent surgery) measurement of its plasma concentration is highly recommended. Currently, there is no single hemostasis test that shows a direct correlation between rivaroxaban plasma levels and anticoagulant efficacy. OBJECTIVES This study was intended to assess the value of ROTEM in determining rivaroxaban administration. MATERIAL AND METHODS Thirteen patients with venous thromboembolism and 13 healthy volunteers were compared with regard to certain ROTEM parameters and anti-FXa activity. The tests were done before the administration of 20 mg rivaroxaban (i.e. 24 h after previous administration) and 2.5 h afterwards. RESULTS The study group demonstrated residual activity of rivaroxaban in plasma (20 ± 11.3 ng/mL) 24 h following the previous administration, which did not cause marked changes in clotting assays compared to controls. In the group, 2.5 h after rivaroxaban administration, prolongation of PT (PTratio 1.51 ± 0.22), APTT (APPTratio: 1.30 ± 0.14) and ROTEM CT (CTratio - EXTEM: 2.45 ± 1.06, CTratio - INTEM 1.32 ± 0.21) were observed. The cut-off values for particular tests were created to determine if the patient had achieved desirable anticoagulant effect after rivaroxaban administration. The mean anti-FXa values were significantly lower in patients before rivaroxaban dosing than after. CONCLUSIONS PT demonstrated better diagnostic value than APTT in rivaroxaban administration. The ROTEM clotting time (CT) according to EXTEM may be used to determine the anticoagulation effect of rivaroxaban, but is not sensitive enough to measure the residual activity of this drug.

The kinetics of hematopoietic niche cytokines and their influence on mobilization efficacy and timing in patients with hematological malignancies.

The bone marrow niche functions are modulated by complicated cytokines network. The aim of our study was to evaluate the levels of VCAM‐1, VEGF, MMP‐9 and SDF during mobilization of CD34+ cells in patients with hematological malignancies. Thirty four patients were enrolled to the study (19F, 15 M) at median age of 57 years. The group consisted of patients with multiple myeloma (26) and lymphoma (8). The mobilization procedures comprised chemotherapy and then G‐CSF. Blood samples were collected before chemotherapy (N = 34) and on the day of the first apheresis (N = 26). Cytokines were evaluated with ELISA assay. We observed significant increase in VCAM‐1 levels during mobilization. On contrary, VEGF and SDF levels decreased during mobilization procedure. The levels of MMP‐9 were stable during mobilization. We divided patients according to baseline cytokines levels below and above median into “low” and “high” expressors. The group of VEGF “low” expressors had longer median time of G‐CSF treatment before first apheresis than ‘high’ expressors. Baseline VEGF levels correlated adversely with duration of G‐CSF treatment before first apheresis. Patients were also divided according to median cytokines levels at apheresis into “low” and “high” expressors. “High” VCAM‐1 expressors had higher CD34+in peripheral blood as well as higher CD34+numbers collected during first apheresis than “low” expressors. In conclusion, the levels of niche cytokines change significantly during mobilization in patients with hematopoietic malignancies. Baseline VEGF can influence timing of mobilization. Higher VCAM‐1 corresponds with higher mobilization efficacy. J. Clin. Apheresis 30:247–251, 2015.

Long-lasting extreme anemia during the therapy of acute lymphoblastic leukemia in a Jehovah's Witness patient.

The treatment of patients with acute leukemia, who due to their religious beliefs refuse to accept blood transfusion, is a great challenge for hematologists.

Assessment of rotation thromboelastometry parameters in patients with essential thrombocythemia at diagnosis and after hydroxyurea therapy.

Patients with essential thrombocythemia suffer from thrombotic complications that are the main source of mortality. Due to its complex pathogenesis, no existing single laboratory method is able to identify the patients at highest risk for developing thrombosis. Twenty patients with essential thrombocythemia at diagnosis, 15 healthy volunteers and 20 patients treated with hydroxyurea were compared with regard to certain rotation thromboelastometry parameters. Clotting time (CT), clot formation time (CFT), &agr;-angle, and maximum clot firmness (MCF) were assessed by using the INTEM, EXTEM, FIBTEM, and NATEM tests. Patients with essential thrombocythemia at diagnosis demonstrated significantly higher mean platelet count and markedly lower mean red blood count than controls. CT and CFT readings were found to be markedly lower in essential thrombocythemia patients at diagnosis than in the control group according to the EXTEM test. Patients at diagnosis had markedly lower CT values (EXTEM, FIBTEM) than patients on hydroxyurea therapy. Alpha angle values were markedly higher in essential thrombocythemia patients at diagnosis than in controls, according to the EXTEM, FIBTEM and NATEM tests. MCF readings were significantly higher in essential thrombocythemia patients at diagnosis than in controls according to EXTEM, INTEM, FIBTEM, and NATEM tests. Patients on hydroxyurea therapy had markedly lower MCF values according to EXTEM test than patients at diagnosis. Patients with essential thrombocythemia demonstrate a prothrombotic state at the time of diagnosis, which is reflected in changes by certain rotation thromboelastometry parameters. The hydroxyurea therapy induces downregulation of the prothrombotic features seen in essential thrombocythemia patients at diagnosis.

Assessment of Selected ROTEM Parameters, Kinetics of Fibrinogen Polymerization and Plasmin Amidolytic Activity in Patients with Congenital Fibrinogen Defects.

BACKGROUND Congenital fibrinogen disorders (CFD) are rare fibrinogen deficiencies which may be quantitative or functional. The clinical course of hypofibrinogenemia (hypoFI) or dysfibrinogenemia (dysFI) is unpredictable and cannot be determined by the application of standard hemostasis tests. OBJECTIVES The main aim of this study was to assess ROTEM parameters in CFD patients. MATERIAL AND METHODS Nine patients with CFD were studied. The fibrinogen concentration was measured functionally and antigenically. EXTEM, INTEM, FIBTEM and APTEM tests were used to measure selected ROTEM parameters, including maximum clot firmness (MCF). Fibrin plasma polymerization, clot lysis and plasmin amidolytic activity were determined by spectrophotometric methods. RESULTS Incorporating the antigenic, ELISA method, to the diagnostic workup allowed the initial diagnosis to be switched from hypoFI to dysFI in 3/7 patients. MCF readings (the most important parameter describing fibrin polymerization capacity) were significantly lower in patients than in controls according to all ROTEM tests. Cases with hypoFI demonstrated markedly lower readings of MCF according to all ROTEM tests than cases with dysFI. All patients demonstrated disturbances of fibrin polymerization process assessed by turbidimetry. In contrast, no marked differences were identified between studied groups in reference to plasmin amidolytic activity. CONCLUSIONS Our data suggests that ROTEM and fibrin plasma polymerization according to the turbidimetric method have a high sensitivity towards detection of different CFD. Although ROTEM MCF assessment may help discriminate patients with hypoor dysfibrinogenemia, this finding has to be confirmed on larger groups of patients.

Implantoprosthetic rehabilitation of a patient with severe form of hemophilia B: a case report

Abstract The preparation of patients with hemophilia before surgical operations and dental procedures constitutes a significant clinical challenge. This article presents the implantoprosthetic rehabilitation of a patient with severe hemophilia B (factor IX activity <1%). The patient was prepared for the surgical procedure with recombinant factor IX concentrate (Rixubis) during the clinical surgery study. Tooth extraction and the implantation of four dental implants in the mandible were planned: one dental implant of 3.7 mm diameter and 10 mm length in the place of tooth 35, and another of 3.2 mm diameter and 10 mm length in the place of tooth 37. The next two implants were implemented 1 month later: one implant 3.7 mm in diameter and 10 mm in length in the place of tooth 46, and another implant 3.2 mm in diameter and 10 mm in length in the area of tooth 44. Appropriate substitution of the missing coagulation factor, together with the use of local hemostatic therapy, allowed dental implantation to be performed without excessive blood loss in this patient with severe hemophilia B.

Acquired haemophilia A in a Jehovah's Witness.

Results from a large multinational clinical trial (guardian3) using prophylactic treatment with turoctocog alfa in paediatric patients with severe haemophilia A: safety, efficacy and pharmacokinetics. Haemophilia 2013; 19: 698–705. 8 Ozelo M, Misgav M, Abdul FA et al. Long-term patterns of safety and efficacy of bleeding prophylaxis with turoctocog alfa (NovoEight((R))) in previously treated patients with severe haemophilia A: interim results of the guardian() 2 extension trial. Haemophilia 2015; 21: e436–9. 9 Verbruggen B, Novakova I, Wessels H, Boezeman J, van den Berg M, MauserBunschoten E. The Nijmegen modification of the Bethesda assay for factor VIII: C inhibitors: improved specificity and reliability. Thromb Haemost 1995; 73: 247– 51. 10 (EMA), E.M.A., Committee for medicinal products for human use (CHMP), guideline on the clinical investigation of recombinant and human plasma-derived factor VIII products. EMA/CHMP/BPWP/144533/ 2009. 2011.