Alena Buliková

Generation of antigen-loaded dendritic cells in a serum-free medium using different cytokine combinations

Dendritic cells (DCs) are antigen-presenting cells that play a critical role in the induction of cytotoxic T-lymphocytes. An optimal method for the generation of DC for clinical use remains to be established. The aim of our study was to find an optimal cytokine combination for DC generation from peripheral blood stem cells (PBSC) and peripheral blood mononuclear cells (PBMC) in serum-free conditions. Serial immunophenotyping enabled us to observe changes in DC content during the culture as well as the development of maturation and activation markers. As a source for DC culture, we used PBSC from patients with multiple myeloma after stem cell mobilization using cyclophosphamide and G-CSF, or PBMC from healthy donors without mobilization. The cells were cultured in a serum-free medium with different cytokine combinations including GM-CSF, TNF-alpha, Flt-3, CD40L, IFN-gamma, IL-1alpha, IL-6, PGE1, and IL-4. The cell cultures were evaluated by immunophenotyping. For PBMC, interleukin-12 assay was performed. For PBSC, the yield of DC as determined by CD83+ cell count ranged from 0. 6 x 10(5) to 30.1 x 10(4) (mean: 9.4 x 10(4)) of DC generated per 1 x 10(6) of initially plated nucleated cells from apheresis. This yield corresponded to (0.3-19.1) x 10(5) (mean: 4.3 x 10(5)) per 1 x 10(6) of CD34+ cells in the apheresis products. For PBMC, the yield was (0.4-24.8) x 10(4) (mean: 2.4 x 10(4)) of DC generated per 1 x 10(6) of initially plated mononuclear cells from venous blood. The cultured cells expressed the mature immunophenotype. No significant differences in cell yield or immunophenotype were detected when comparing different cytokine combinations.

FEIBA in treatment of acute bleeding episodes in patients with haemophilia A and factor VIII inhibitors: a retrospective survey in regional haemophilia centre.

Summary.  FEIBA® (factor eight inhibitor by‐passing activity) is used to achieve haemostasis in haemophiliacs with inhibitor. The aim of this study was to evaluate efficacy and consumption of the product in treatment of haemorrhages in haemophiliacs with factor VIII inhibitor, and determine factors that can influence the results of treatment. We used data from our haemophilia centre from years 2000–2008. Six haemophiliacs with factor VIII inhibitor were treated on demand with FEIBA® for 61 bleeding episodes (45 haemarthroses, six muscle bleeds, six other sites bleeds and four multiple sites bleeds). The median cumulative dose of FEIBA® per bleeding episode was 205 U kg−1. Bleeding was stopped in 96.7% (59 of 61) of events but re‐bleeding occurred in 3 events (4.9%) within 48 h after cessation of bleeding. In home treatment (20 of 61) bleeding stopped in 90% (18 of 20) without recurrence and the median consumption per event was reduced to 153 U kg−1. Without the use of home treatment the median consumption was 250 U kg−1 per event and bleeding ceased definitely in 92.7% (38 of 41) of cases. The cumulative dose of FEIBA® was lower for three episodes with re‐bleeding: median 96 U kg−1 but not in the two cases of ineffective treatment: 361 U kg−1. FEIBA® in management of bleeding episodes completely resolved the haemorrhage in 91.8% of events and in a further 4.9% if treatment was restarted. Using home treatment saved expenditure due to the lower cumulative dose needed for treatment of haemorrhage.

Generation of Dendritic Cells Using Cell Culture Bags -Description of a Method and Review of Literature.

Abstract Anticancer immunotherapy using dendritic cell-based vaccines is a strategy aimed at the induction and maintenance of immune responses against cancer cells. Clinical applications of dendritic cells (DCs) require stringent adherence to Good Manufacturing Practice (GMP) methods and rigorous standardization of DC-based vaccine preparation. Recently, closed systems for DC culture have been developed with a goal to minimize the risk of contamination. Here, we compare the yield, immunophenotype, and functional properties of DCs generated in Lifecell X-Fold culture bags and in plastic wells, both from adherence-selected monocytes, and review the current literature on closed systems for DC generation. We found that both the overall yield and the yield of CD83+ cells in cell culture bags was lower than in the standard culture method. No statistically significant differences were observed in the expression of DC immunophenotypic markers. The capability of DCs cultured in bags and in wells to induce the proliferation of allogeneic mononuclear cells were equivalent. The performance of DCs in mixed lymphocyte reaction correlated significantly (p=0.005) with the CD83 expression but not with the CD80, CD86, HLA-DR, CD1a, and CD1c expression. We conclude that the immunophenotype and stimulatory properties of DCs cultured in closed cell culture bags are similar to those generated by conventional method using cell culture wells.

Increasing procoagulant activity of circulating microparticles in patients with Philadelphia-negative myeloproliferative neoplasms: a single-centre experience.

Microparticles are small membrane fragments with dimension between 0.1 and 1 &mgr;m, which are released during cell activation or apoptosis, exposing the phospholipid phosphatidylserine and membrane antigens typical for cellular origin. Philadelphia-negative myeloproliferative neoplasms (MPNs) are characterized by an increased risk of thrombosis. Data from literature suggest an association between thrombosis and the procoagulant activity of microparticles. Association between the procoagulant activity of microparticles and the incidence of thrombosis was assesed in a group of 126 patients with Philadelphia-negative MPNs. Measurement of microparticles procoagulant activity was performed using a functional assay, namely the Zymuphen MP-activity (Hyphen Biomed, Neuville-sur-oise, France). A total of 539 samples were analysed within this group of patients, regardless of patients’ state of health. A significantly higher circulating microparticles procoagulant activity was found in MPN patients as compared with the control group (P < 0.001). A pathological level of procoagulant activity was observed more frequently in patients with polycythaemia vera (88%, P = 0.002) than groups of patients with essential thrombocythaemia (73.2%) and primary myelofibrosis (68.3%); the same result was confirmed in patients with a history of venous thrombosis in comparison with patients without thrombosis (84.7 vs. 73.2%, P = 0.029). Patients without cytoreductive treatment had a higher activity of microparticles (P = 0.010). Furthermore, presence of JAK2 V617F mutation was associated with an increased procoagulant activity (P = 0.007), as well as the higher JAK2 V617F allele burden (P = 0.001). Further prospective clinical studies will be necessary to evaluate the clinical relevance of microparticles in the prediction hypercoagulable state in these patients.

Antiphospholipid Syndrome: Changing Knowledge During the Time – The ”Four P” Pattern

The antiphospholipid syndrome has been described for the first time by Graham Hughes in 1983 as a condition connected with thromboses or foetal losses and antiphospholipid antibodies presence. Form that time there has been a great progress in knowledge, including antiphospholipid antibodies characterisation, their probable and also possible action, clinical manifestations, laboratory detection and treatment possibilities. This book provides a wide spectrum of clinical manifestations through Chapters written by well known researchers and clinicians with a great practical experience in management of diagnostics or treatment of antiphospholipid antibodies presence.