Management of adults and children receiving CAR T-cell therapy: 2021 best practice recommendations of the European Society for Blood and Marrow Transplantation (EBMT) and the Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association (EHA).

BACKGROUND: Several commercial and academic autologous chimeric antigen receptor T-cell (CAR-T) products targeting CD19 have been approved in Europe for relapsed/refractory B-cell acute lymphoblastic leukemia, high-grade B-cell lymphoma and mantle cell lymphoma. Products for other diseases such as multiple myeloma and follicular lymphoma are likely to be approved by the European Medicines Agency in the near future. DESIGN: The European Society for Blood and Marrow Transplantation (EBMT)-Joint Accreditation Committee of ISCT and EBMT (JACIE) and the European Haematology Association collaborated to draft best practice recommendations based on the current literature to support health care professionals in delivering consistent, high-quality care in this rapidly moving field. RESULTS: Thirty-six CAR-T experts (medical, nursing, pharmacy/laboratory) assembled to draft recommendations to cover all aspects of CAR-T patient care and supply chain management, from patient selection to long-term follow-up, post-authorisation safety surveillance and regulatory issues. CONCLUSIONS: We provide practical, clinically relevant recommendations on the use of these high-cost, logistically complex therapies for haematologists/oncologists, nurses and other stakeholders including pharmacists and health sector administrators involved in the delivery of CAR-T in the clinic.

Adenovirus infection among pediatric patients with cancer and in pediatric recipients of hematopoietic stem cell: A multicenter nationwide study.

The aim was to evaluate the incidence, clinical course, and outcome of adenoviral infection (AdVI) in pediatric patients diagnosed and treated due to cancer and in pediatric recipients of hematopoietic stem cell. Over a 72-month period, all-in 5599 children with cancer: 2441 patients with hematological malignancy (HM) and 3158 with solid tumors (ST), and 971 patients after transplantation: 741 after allogeneic (allo-HSCT) and 230 after autologous (auto-HSCT) were enrolled into the study. Among cancer patients, 67 episodes of AdVI appeared in 63 (1.1%) children, including 45 (1.8%) with HM and 18 (0.6%; P < .001) with ST. Within transplanted patients, AdVIs were responsible for 88 episodes in 81 (8.3%) children (P < .001), including 78 (10.5%) patients after allo-HSCT and 3 (1.3%) after auto-HSCT. Time to develop AdVI was short, especially after allo-HSCT. The most common clinical manifestation in cancer patients was enteritis diagnosed in 63 (94.0%) cases, while among HSCT recipient asymptomatic adenoviremia was found in 36 (40.9%) cases and the most common clinical manifestation was urinary tract infection. Cancer patients with disseminated disease, as well as HSCT recipients with either asymptomatic viremia or disseminated disease, received antiviral treatment. The most commonly used first-line therapy was cidofovir. None of the cancer patients died due to AdVI, while within HSCT recipients three patients developed disseminated adenoviral disease and died despite antiviral treatment. In cancer patients, AdVIs are rare and associated with very good prognosis even without specific treatment. However, in allo-HSCT recipients, disseminated disease with fatal outcome is more likely to occur.

Hematopoietic stem cell transplantation does not increase the risk of infection-related complications for pediatric patients with Hodgkin and non-Hodgkin lymphomas: A multicenter nationwide study.

BACKGROUND: Hodgkin (HL) and non-Hodgkin lymphoma (NHL) represent a spectrum of lymphoid malignancies that are often curable with currently applied treatment regimens; however, 15%-30% of lymphoma patients still suffer from relapsed or refractory (rel/ref) disease. Although hematopoietic stem cell transplantation (HSCT) improves outcomes of second-line therapy for lymphoma in childhood, the complication rates in this group of patients, especially infectious complications (IC), remain unclear. OBJECTIVE: The aim of this population-based cohort study was a retrospective analysis of incidence, epidemiology and profile of bacterial infections (BI), invasive fungal disease (IFD), and viral infections (VI) in primary or rel/ref lymphoma patients, both HL and NHL. PATIENTS AND METHODS: We subdivided lymphoma patients into three groups: patients with primary conventional chemotherapy/radiotherapy regimens (group A), patients with rel/ref lymphoma treated with second-line chemotherapy (group B), and rel/ref lymphoma patients who underwent HSCT (group C). The medical records of the patients were biannually reported by each pediatric oncology center, and the data were analyzed centrally. RESULTS: Within 637 patients with primary lymphoma, at least one IC was diagnosed in 255 (40.0%), among 52 patients with rel/ref lymphoma 24 (46.2%) ICs were observed, and in transplanted group, 28 (57.1%) out of 49 children were diagnosed with IC (P = .151). The distribution of etiology of IC differed between the patient groups (A, B, C), with a predominance of BI in group A (85.6% vs 72.0% and 47.9%, respectively), VI in group C (9% and 16.0% vs 46.6%, respectively), and IFD in group B (5.4% vs 12.0% vs 5.5%, respectively). Overall, 500 (68.0%) episodes of bacterial IC were diagnosed in the entire group. Apart from HL patients treated with chemotherapy, in all the other subgroups of patients Gram-positives were predominant. The rate of multidrug-resistant bacteria was high, especially for Gram-negatives (41.1% in group A, 62.5% in group B, and 84.6% in group C). The infection-related mortality was comparable for each group. CONCLUSIONS: The incidence of IC was comparable during first- and second-line chemotherapy and after HSCT, but their profile was different for primary or re/ref lymphoma and depended on the type of therapy.

Multidrug-resistant bacterial infections in children undergoing haematopoietic stem cell transplantation over a 6-year period: analysis of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation.

AIMS: Multidrug-resistant (MDR) bacteria are an emerging cause of morbidity and mortality after haematopoietic stem cell transplantation (HSCT). The aim of the study was to analyse the incidence, clinical characteristics and survival from bacterial infections (BI) caused by MDR pathogens in paediatric HSCT recipients. METHODS AND RESULTS: Among 971 transplanted patients, BI were found in 416 children between the years 2012 and 2017. Overall, there were 883 bacterial episodes, which includes 85·8% after allo-HSCT and 14·2% after auto-HSCT. MDR strains were responsible for half of the total number of bacterial episodes. Over 50% of MDR pathogens were Enterobacteriaceae causing mainly gut infections or urinary tract infections. CONCLUSIONS: Regarding HSCT type, we did not find differences in the profile of MDR BI between allo- and auto-HSCT recipients. However, survival in MDR and non-MDR infections was comparable. SIGNIFICANCE AND IMPACT OF THE STUDY: The large sample size enables unique analysis and makes our data more applicable to other paediatric HSCT centres. In the absence of local epidemiological data, presented clinical characteristics of MDR-caused infections may be used to optimize the prophylactic strategies, early identification of infectious complications of MDR aetiology and thus promptly initiate adequate antibiotic therapy and further improve patients' outcome.

Incidence, course, and outcome of Clostridium difficile infection in children with hematological malignancies or undergoing hematopoietic stem cell transplantation.

Clostridium difficile infection (CDI) is one of the most common causes of nosocomial infectious diarrhea in children during anticancer therapy or undergoing hematopoietic stem cell transplantation (HSCT) in Europe. Immunosuppression in these patients is a risk factor for CDI. Malignant diseases, age, acute graft-versus-host disease (aGVHD), HLA mismatch, or use of total body irradiation may play an important role in CDI course. The aim of this study was to evaluate the incidence, course, and outcome of CDI in children treated for malignancy or undergoing HSCT. Between 2012 and 2015, a total number of 1846 patients were treated for malignancy in Polish pediatric oncological centers (PHO group) and 342 underwent transplantation (HSCT group). In PHO group, episodes of CDI occurred in 210 patients (14%). The incidence of CDI was higher in patients with hematological malignancies in comparison to that with solid tumors. Patients with acute myeloblastic leukemia had shorter time to episode of CDI than those with acute lymphoblastic leukemia. Patients over 5 years and treated for acute leukemia had more severe clinical course of disease in PHO group. In HSCT group, CDI occurred in 29 (8%) patients. The incidence of CDI was higher in patients transplanted for acute leukemia. The recurrence rate was 14.7% in PHO and 20.7% in HSCT patients. CDI incidence was highest in patients with hematological malignancies. Most of patients experienced mild CDI. Age < 5 years and diagnosis other than acute leukemia were the positive prognostic factors influencing clinical CDI course.

Bacterial infections in pediatric hematopoietic stem cell transplantation recipients: incidence, epidemiology, and spectrum of pathogens: report of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation.

BACKGROUND: Infectious complications are a significant cause of hematopoietic stem cell transplantation (HSCT) failure, especially allogeneic HSCT (allo-HSCT) because of delayed immune reconstitution and graft-versus-host disease (GVHD) occurrence. Identifying the factors responsible for bacterial infections (BI) in patients undergoing HSCT will provide much more effective empirical antimicrobial treatment in this group of patients. OBJECTIVE: The aim of this study was to evaluate the epidemiology and profile of BI in patients after HSCT in 5 centers of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation in 2012-2013. PATIENTS AND METHODS: In 308 HSCT recipients, we retrospectively analyzed 273 episodes of BI in 113 (36.7%) children aged 0.02-22 years (median age: 7 years), 92 after allo-HSCT and 22 after autologous HSCT (auto-HSCT). We assessed incidence of BI in different HSCT types by calculating the Index of Bacterial Infection (IBI) as a ratio of patients with at least 1 BI to all patients who underwent this type of HSCT in the analyzed period. We assessed the profile of BI with particular emphasis on multidrug-resistant organisms, and impact of underlying disease and of graft-versus-host disease on BI episodes. RESULTS: In the studied group, 273 episodes of BI were diagnosed, including 237 episodes after allo-HSCT and 36 after auto-HSCT. Among allo-HSCT recipients diagnosed with at least 1 BI, the IBI was 0.4 (matched sibling donor-HSCT 0.3; matched donor-HSCT 0.4; mismatched unrelated donor [MMUD]-HSCT 0.8; P = 0.027) and after auto-HSCT 0.3 per 1 transplanted patient. In patient after allo-HSCT because of myelo- or lymphoproliferative diseases and bone marrow failures, the major cause of infections was Enterobacteriaceae, while gram-positive bacteria predominated in the group with primary immunodeficiencies. In all patients after auto-HSCT, the dominant pathogen of BI were Enterobacteriaceae (P = 0.011). Time from each type of HSCT to infection caused by different pathogens did not differ significantly. CONCLUSIONS: The risk of BI does not depend on the underlying disease, but only on HSCT donor type and is the highest after MMUD-HSCT procedure. The profile of BI depends on the underlying disease and HSCT donor type, but does not depend on the occurrence of acute GVHD. Gram-negative bacteria predominated in patients with myelo- and lymphoproliferative diseases, while in patients with primary immunodeficiencies gram-positive strains were predominant.

Current practices used for the prevention of central venous catheter-associated infection in hematopoietic stem cell transplantation recipients: a survey from the Infectious Diseases Working Party and Nurses' Group of EBMT.

BACKGROUND: Central line-associated bloodstream infection (CLABSI) is one of the most common infectious complications after hematopoietic stem cell transplantation. To prevent this complication, international guidelines recommend the implementation of the CLABSI 'prevention bundle' consisting of hand hygiene, full barrier precautions, cleaning the insertion site with chlorhexidine, avoiding femoral sites for insertion, and removing unnecessary catheters. The aim of this survey was to analyze to what extent European Group for Blood and Marrow Transplantation (EBMT) centers have included the CLABSI prevention bundle in practice. METHODS: A questionnaire used for data collection was sent to the 545 EBMT centers worldwide, 103 of which responded. RESULTS: All 5 components of the CLABSI prevention bundle were recorded in 28% of the centers' standard operating procedures (SOP), and 21% of the centers answered that they used all of the bundle components in clinical practice. The most common recommendation absent from the SOP was specification of all the components of full barrier precautions (43% of the centers did not include at least 1 component). Skin disinfection with chlorhexidine before catheter insertion was reported by 66% centers. CLABSI rates were monitored in 21% of centers. CONCLUSIONS: Although most of the centers lacked 1 or more of the CLABSI prevention bundle components in their SOP, improvements could easily be made by updating the centers' SOP. The first important step is introduction of CLABSI rate monitoring in this high-risk patient population.

Allogeneic stem cell transplantation for patients with advanced rhabdomyosarcoma: a retrospective assessment.

BACKGROUND: Allogeneic haematopoietic stem cell transplantation (allo-SCT) may provide donor cytotoxic T cell-/NK cell-mediated disease control in patients with rhabdomyosarcoma (RMS). However, little is known about the prevalence of graft-vs-RMS effects and only a few case experiences have been reported. METHODS: We evaluated allo-SCT outcomes of 30 European Group for Blood and Marrow Transplantation (EBMT)-registered patients with advanced RMS regarding toxicity, progression-free survival (PFS) and overall survival (OS) after allo-SCT. Twenty patients were conditioned with reduced intensity and ten with high-dose chemotherapy. Twenty-three patients were transplanted with HLA-matched and seven with HLA-mismatched grafts. Three patients additionally received donor lymphocyte infusions (DLIs). Median follow-up was 9 months. RESULTS: Three-year OS was 20% (s.e.±8%) with a median survival time of 12 months. Cumulative risk of progression was 67% (s.e.±10%) and 11% (s.e.±6%) for death of complications. Thirteen patients developed acute graft-vs-host disease (GvHD) and five developed chronic GvHD. Eighteen patients died of disease and four of complications. Eight patients survived in complete remission (CR) (median: 44 months). No patients with residual disease before allo-SCT were converted to CR. CONCLUSION: The use of allo-SCT in patients with advanced RMS is currently experimental. In a subset of patients, it may constitute a valuable approach for consolidating CR, but this needs to be validated in prospective trials.

Outcome of treatment of Epstein-Barr virus-related post-transplant lymphoproliferative disorder in hematopoietic stem cell recipients: a comprehensive review of reported cases.

Post-transplant lymphoproliferative disorder (PTLD) caused by Epstein-Barr virus (EBV) is an important complication in high-risk allogeneic hematopoietic stem cell transplant (HSCT) recipients. Before the current methods of anti-EBV therapy were introduced, the mortality from PTLD after HSCT was >80%. With current approaches the mortality from EBV-PTLD can be significantly reduced. The published literature and meeting abstracts were reviewed to assess the impact of different management strategies against EBV-PTLD. This analysis of reported outcomes indicates that preemptive use of rituximab and EBV-cytotoxic T lymphocytes (CTL) significantly reduced the risk of death due to EBV-PTLD in HSCT recipients with survival rates of 89.7% and 94.1%, respectively. Therapy of established PTLD also reduced the risk of fatal outcome. However, the overall success rates were lower than after preemptive therapy, reaching 63% and 88.2% of total EBV-DNA clearance with rituximab and CTL therapy, respectively. A reduction of immunosuppression and/or donor lymphocyte infusion might also reduce the risk of death due to EBV-PTLD. Although it is difficult to estimate these effects more precisely because of the frequent use of combination therapies, the responses to these modalities can be estimated to be 56.6% and 41.0%, respectively. Finally, chemotherapy seems not to contribute to improved survival of patients with PTLD after HSCT and antiviral agents are not active against PTLD.

Imatinib is a substrate for various multidrug resistance proteins.

UNLABELLED: An increasing resistance to imatinib is an emerging problem in patients with chronic myeloid leukemia (CML). The aim of the study was to asses mechanisms related to cellular drug resistance in imatinib-resistant derivates of chronic myeloid leukemia K-562 cell line. A parental K-562 and its imatinib-resistant derivate cell lines were used. Cell lines were tested for cytotoxicity of imatinib, cytarabine, busulfan and etoposide by the MTT assay. The cytotoxicity was expressed as IC50, inhibitory concentration for 50% of cells. Multidrug resistance proteins expression, rhodamine retention and daunorubicin accumulation were measured for each cell line. Continuous exposition of K-562 cell line to 0.01-0.02 mM imatinib resulted in development of resistance, while exposition to 0.1 microM imatinib increased cell sensitivity to this drug. There was a high correlation between PGP, MRP1 and LRP expression and IC50 values for imatinib and etoposide. All tested cell lines were highly resistant to cytarabine. Rhodamine retention alone and in the presence of cyclosporine was the lowest in imatinib-resistant K-562R-0.1 cell line, what suggest high PGP activity in this cell line. The highest daunorubicin accumulation was observed in parental K-562 cell line, while it was lower in imatinib-resistant cell lines. These data suggest that imatinib is a substrate for multidrug resistance proteins, and an increased expression of PGP, MRP1 and LRP play a role in resistance to imatinib in CML. KEYWORDS: imatinib, multidrug resistance proteins, chronic myeloid leukemia, PGP, MRP1, LRP.

Management of CMV, HHV-6, HHV-7 and Kaposi-sarcoma herpesvirus (HHV-8) infections in patients with hematological malignancies and after SCT.

These recommendations were prepared by the European Conference on Infections in Leukaemia following a predefined methodology. Literature searches were made to identify studies pertinent to management of CMV, HHV-6, -7 and -8 infections. For CMV, 76 studies were reviewed: 72 published and 4 presented as abstracts. Twenty-nine of these studies were prospective randomized trials. For the other herpesviruses, HHV-6, -7 and -8, no randomized controlled trial has been performed, although data from some studies with other primary endpoints have been used to assess the management of HHV-6 infection. Works presented only as abstracts were used to a very limited extent. The quality of evidence and level of recommendation were graded according to the Center for Disease Control (CDC) criteria.

Incidence of Infectious Complications in Children With Acute Lymphoblastic Leukemia Treated With Hematopoietic Stem Cell Transplantation.

OBJECTIVE: We analyzed incidence and profile of infections in children with acute lymphoblastic leukemia (ALL) treated with hematopoietic stem cell transplantation (HSCT) in Polish pediatric HSCT departments, over a 2-year period. PATIENTS AND METHODS: Hospital records of 67 patients, who underwent allogeneic HSCT for ALL, were analyzed retrospectively for microbiologically documented infection: bacterial infection (BI), viral infection (VI), and fungal infection (FI). The majority of patients (40/67; 59.7%) underwent HSCT from matched unrelated donors (MUD). RESULTS: In total, 84 BI in 31 patients, 93 VI in 50 patients, and 27 FI in 22 patients were diagnosed. No differences were found in the frequency of occurrence of BI according to the type of transplant (P = .16); the occurrence of VI was statistically more frequent in MUD transplant recipients as compared with matched sibling donors (MSD) and mismatched related donors (MMFD; P = .001) and there was a trend in MUD patients for the higher occurrence of FI in comparison with MSD and MMFD transplants (P = .08). Regarding disease status, the occurrence of BI, VI, and FI was statistically more frequent in children who underwent transplantation in their first complete remission (CR1), rather than those who underwent transplantation in ≥CR2 (P < .05). In conclusion, infectious complications are an important cause of morbidity in children with ALL treated with allogeneic HSCT and the incidence of infections is high in this group of patients.

Use of haploidentical stem cell transplantation continues to increase: the 2015 European Society for Blood and Marrow Transplant activity survey report.

Hematopoietic stem cell transplantation (HSCT) is an established procedure for many acquired and congenital disorders of the hematopoietic system. A record number of 42 171 HSCT in 37 626 patients (16 030 allogeneic (43%), 21 596 autologous (57%)) were reported by 655 centers in 48 countries in 2015. Trends include continued growth in transplant activity over the last decade, with the highest percentage increase seen in middle-income countries but the highest absolute growth in the very-high-income countries in Europe. Main indications for HSCT were myeloid malignancies 9413 (25%; 96% allogeneic), lymphoid malignancies 24 304 (67%; 20% allogeneic), solid tumors 1516 (4%; 3% allogeneic) and non-malignant disorders 2208 (6%; 90% allogeneic). Remarkable is the decreasing use of allogeneic HSCT for CLL from 504 patients in 2011 to 255 in 2015, most likely to be due to new drugs. Use of haploidentical donors for allogeneic HSCT continues to grow: 2012 in 2015, a 291% increase since 2005. Growth is seen for all diseases. In AML, haploidentical HSCT increases similarly for patients with advanced disease and for those in CR1. Both marrow and peripheral blood are used as the stem cell source for haploidentical HSCT with higher numbers reported for the latter.

Resistance to glucocorticoids in childhood acute lymphoblastic leukemia: impact of relationship between ex vivo sensitivity and in vivo concentration on risk factor analysis.

Resistance to glucocorticoids remains one of the main obstacles in therapy of childhood acute lymphoblastic leukemia (ALL). The aim of the study was the analysis of relationship between ex vivo drug resistance of prednisolone and dexamethasone and exposure to these drugs in childhood ALL, with respect to risk factor analysis. Ex vivo resistance to both glucocorticoids was compared to maximum drug concentration achievable in body fluids, calculated in mathematical model. Drug resistance to vincristine and L-asparaginase, expression of multidrug resistance and apoptosis proteins was also determined. Concentration of both glucocorticoids in extracellular fluid was higher than drug resistance in the following groups of patients: in initial ALL patients, in patients staying in remission during follow-up, and in prednisolone good responders. Factors significant by multivariate analysis were early bone marrow response by day 15 and concentration of prednisolone higher than ex vivo prednisolone resistance. For initial ALL patients with determined response to initial prednisolone monotherapy, factors significant by univariate analysis were early bone marrow response, and exposure to glucocorticoids higher than ex vivo resistance to these drugs. No factor was significant by multivariate analysis in this group. Risk factor analysis showed that concentration of prednisolone and dexamethasone higher than respective ex vivo drug resistance, is a strongest prognostic factor in childhood ALL.

Increased risk of infections and infection-related mortality in children undergoing haematopoietic stem cell transplantation compared to conventional anticancer therapy: a multicentre nationwide study.

This nationwide multicentre study analysed the epidemiology of bacterial, viral and fungal infections in paediatric haematopoietic stem cell transplantation (HSCT) and paediatric haematology and oncology (PHO) patients over a period of 24 consecutive months, including incidence, hazard risk and outcome of infections as well as occurrence of multidrug-resistant bacteria. During this period, 308 HSCTs were performed and 1768 children were newly diagnosed for malignancy. Compared to PHO, the risk in HSCT patients was significantly higher for all infections (hazard ratio (HR) 2.7), bacterial (HR 1.4), fungal (HR 3.5) and viral (HR 15.7) infections. The risk was higher in allo- than auto-HSCT for bacterial (HR 1.4), fungal (HR 3.2) and viral (HR 17.7) infections. The incidence of resistant bacteria was higher in HSCT than in PHO patients for both G-negative (72.5% vs. 59.2%) and G-positive (41.4% vs. 20.5%) strains. Cumulative incidence of bacterial, fungal and viral infections in HSCT patients was 33.9, 22.8 and 38.3%, respectively. Cumulative incidence of viral infections in allo-HSCT was 28.0% for cytomegalovirus, 18.5% for BK virus, 15.5% for Epstein-Barr virus, 9.5% for adenovirus, 2.6% for varicella zoster virus, 0.9% for influenza, 0.9% for human herpesvirus 6 and 0.3% for hepatitis B virus. Survival rates from infections were lower in HSCT than in PHO patients in bacterial (96.0 vs. 98.2%), fungal (75.5 vs. 94.6%) and most viral infections. In conclusion, the risk of any infections and the occurrence of resistant bacterial strains in allo-HSCT patients were higher than in auto-HSCT and PHO patients, while the outcome of infections was better in the PHO setting.

Anti-HBs profiles in children treated for neoplastic disease who had been vaccinated against hepatitis B postnatally or as infants.

Children with cancer are a risk group for hepatitis B virus (HBV) infection. In Poland, the initiation of a national HBV vaccination programme in neonates and infants in 1995 has contributed to the prevention of HBV infection in children treated for neoplastic diseases. The objective of this study was to analyse the anti-HBs pattern and occurrence of HBV infections in children with cancer who had been vaccinated during infancy. The study included 96 children divided into three groups: Group A, children who had received a full vaccination course with an initial level of anti-HBs >/=100 IU/L; Group B, children who had received a full vaccination course with anti-HBs <100 IU/L, for whom an additional dose of vaccine was administered; and Group C, children who had further immunoprophylaxis because they did not complete the vaccination course before cancer diagnosis. A protective level of anti-HBs after the full vaccination programme was found in 80.5% of children after three months, 74.2% after six months, 61.5% after 12 months and 78.6% after 18 months. Among children who produced antibodies, a slow decrease in the level of anti-HBs was observed. It was still protective during follow-up in Group A, but occasionally fell below 100 IU/L in Group B. In Group C, five of 11 subjects had a protective level of anti-HBs throughout follow-up. Of 28 children who showed the presence of HBsAg during follow-up, 23 eradicated the virus. In children with cancer vaccinated against HBV according to the vaccination schedule, the immune response maintains a protective level of anti-HBs in more than 60% of cases, despite immunosuppression.

Dexrazoxane has no impact on sensitivity of childhood leukemic blasts to daunorubicin.

Dexrazoxane (DEX) prevents the formation of free radical, lipid peroxidation and cardiotoxicity caused by anthracyclines. Due to a concern about its possible interference with anthracyclin cytotoxicity, the in vitro effect of DEX on daunorubicin (DNR) cytotoxicity, cell cycle and induction of apoptosis by annexin-V was investigated. The sensitivity to DEX, DNR and their combination was tested by the MTT assay in human promyelocytic leukemia HL-60, the erythroid blast crisis CML K562 cell lines and in 45 children with ALL and AML. Cell cycle analysis and annexin-V expression were performed by flow cytometry. It has been observed that DEX itself weakly, but significantly caused cytotoxicity in both cell lines and in patient samples, especially in initial ALL samples. DEX sensitized K562 and HL60, but not patient samples, to cytotoxicity of DNR. The percentage of necrotic/apoptotic cells, as detected in cell cycle analysis and annexin V staining, was higher after exposure to DEX +/- DNR, when compared to respective samples not treated with DEX, in both cell lines but not in patient samples. Expression of annexin V induced by DEX in both cell lines was enlarged, regardless of the presence of DNR. This difference was not observed in patient samples, however, the number of cells expressing annexin V was higher after exposure to DEX +/- DNR in comparison to respective samples not treated with DEX. In conclusion, it seems that DEX possibly has no impact on the sensitivity of childhood leukemic blasts to DNR, however, has weak cytotoxic properties itself.

The effect of doxorubicin on the expression of cyclin A in K-562 leukemia cell line.

Two opposite processes such as apoptosis and cell division cycle play an important role in cancer biology. During apoptosis cells die by degrading proteins and genome, whereas in the cell cycle cells divide and the genome is duplicated. There are very few studies on the role of cell cycle proteins in apoptosis although their role is distinctly different from that in the cell cycle. The significance of expression of cyclin A and other cyclin cell proteins (eg. Cdk2) in apoptosis remains to be investigated. The aim of this study was to characterize the distribution pattern of cyclin A by using the stereptavidin - biotin - peroxidase technique in K-562 cells treated with doxorubicin. The analysis of cell cycle phases using cytophotometric methods to estimate the cellular response to doxorubicin was also used. Studied cells were treated with doxorubicin in the range 0.5; 5.0 and 10 microM. Expression of cyclin A in K-562 was 32.2; 41.8; 69.9%, respectively, according to doses of doxorubicin. The number of apoptotic cells was increasing together with the increase of doxorubicin doses as well as positive labeling for cyclin A. After doxorubicin treatment decrease of G1/G0 phase and the growth of cell percentage with dose dependent manner at G2/M phase, compared to control was observed. The results allow to suggest that expression of cyclin A may have pro-apoptotic role however more studies are required to clarify whether and what role cyclin A plays in apoptosis.

In vitro sensitivity of leukemic cells to nucleoside derivatives in childhood acute leukemias: good activity in leukemic relapses.

Nucleoside analogues such as fludarabine and cladribine are used in therapy of indolent lymphomas and leukemias in adults, while cytarabine is used mainly in protocols for acute leukemias. Mechanisms of their activity is based on inhibition of enzymes involved in DNA, RNA and protein synthesis. The objective of the study was the analysis of in vitro cellular drug sensitivity in childhood acute lymphoblastic (ALL) and myeloid (AML) leukemia. Isolated leukemic cells obtained from 264 patients, including 152 initial ALL, 45 relapsed ALL, 54 initial AML and 13 relapsed AML were tested for cytotoxicity for fludarabine, cladribine, and cytarabine by the MTT assay. Drug concentration lethal to 50% of tested cells was regarded as a value of drug resistance. Three tested nucleoside analogues showed highest cytotoxicity against initial ALL samples. Samples of relapsed ALL and initial AML were more resistant than ALL de novo ones. Unexpectedly, no differences were observed between initial and relapsed AML samples for all tested drugs, what suggests that nucleoside analogues are active drugs in relapsed AML, which is commonly regarded as a resistant disease. All tested drugs presented significant cross-resistance in each of analyzed subgroups. In summary, tested nucleoside analogues presented relatively good activity against childhood leukemias at relapse stage.

Pretransplant vaccinations in allogeneic stem cell transplantation donors and recipients: an often-missed opportunity for immunoprotection?

Immune deficiency following hematopoietic cell transplantation predisposes the patient to potentially deadly infections. Vaccinations can improve immunity and thus reduce the morbidity and mortality associated with these infections. Over the years different sets of guidelines have been published the most recent by the Infectious Diseases Society of American (IDSA). There is limited evidence that vaccination of donors and/or recipients before transplantation may improve immunity. However, despite the possibility of augmented immunity, there remain logistical, ethical and medical concerns about such a vaccination strategy.