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.

First-line immunosuppressive treatment in children with aplastic anemia: rabbit antithymocyte globulin.

Immunosuppressive therapy is the treatment of choice in children with acquired severe aplastic anemia (AA) and no HLA-matched family donor. The paper presents results of a multicenter study of 63 children with AA treated with rabbit antithymocyte globulin (r-ATG) and cyclosporine A as the first line treatment in the years 1996-2012. Therapeutic effects were evaluated at Days 112, 180, and 360. At Day 112, remission was achieved in 28 out of the 63 patients (44.4 %), complete remission in 10 patients (15.9 %), and partial remission in 18 (28.5 %). At Day 180, 31 patients (49.2 %) were in remission including 15 cases in complete (23.8 %), and 16 cases in partial remission (25.4 %). One year after therapy onset, 34 patients (64.9 %) were in remission including 24 patients (38.0 %) in complete and 10 (15.9 %) in partial remission. Relapse occurred in 4 patients, from 8 months up to 2 years and 2 months after remission. One child, 5 years after remission, was diagnosed with paroxysmal nocturnal hemoglobinuria. The estimated 10-year overall survival rate and 10-year event-free survival rate were 67 % and 57 %, respectively.

Clinical experience with Optivate®, high-purity factor VIII (FVIII) product with von Willebrand factor (VWF) in young children with haemophilia A.

Optivate® is a high-purity FVIII/VWF product. Its safety, tolerability and efficacy in subjects ≥ 12 years have been demonstrated. This study was undertaken to assess Optivate® in children with haemophilia A. Twenty-five children, including one PUP (previously untreated patient), aged 1-6 years (mean 4.67 years) were treated with Optivate® for 26 weeks. Inhibitors were assessed every 3 months and viral status at the study start and end. Prophylaxis was used by five boys and on demand by twenty. The mean number of bleeds in the study was lower compared to the same period pre-study (12.0/child vs. 16.2/child), with fewer bleeds (P < 0.05) in the prophylactic subgroup (8.0/child) compared with the on-demand sub-group (13.4/child). Fourteen major bleeds were reported, all by the on-demand sub-group. Children on prophylaxis were administered a mean of 59.4 infusions; on-demand group 35.1 infusions. A total of 998 infusions were used with a mean dose of 29.1 IU kg⁻¹, and a mean of 38.6 exposure days (ED). Children < 4 years used higher doses, and reported fewer bleeds than older children. Children's Parents/Guardians rated Optivate® as helpful or very helpful in controlling 97.5% of bleeds by the prophylactic group, and in 98.5% of the bleeds in the on-demand group. Only 5 of 101 ADRs were treatment-related events (5%), all were mild and non-serious. There were no clinically significant changes in vital signs, viral transmissions or inhibitors. In young children Optivate® was well tolerated, safe and efficacious.

Haematopoietic stem cell transplantation in children in eastern European countries 1985-2004: development, recent activity and role of the EBMT/ESH Outreach Programme.

The paediatric population of 19 eastern European countries amounts to approximately 80 million children. Between 1985 and 2004, the number of centres performing haematopoietic stem cell transplantation (HSCT) in children increased from 1 in 1985 to 24 in 2004 and the yearly number of paediatric HSCTs rose from 1 in 1985 to 291 in 2004. Altogether, 2342 transplants were reported to the EBMT Registry during this time (Poland 953, Czech Republic 501, Hungary 269, Russia 217, Croatia 129, Slovakia 71, Bulgaria 45, Serbia and Montenegro 36, Slovenia 35, Belarus 33, Estonia 26, Lithuania 19 and Romania 8). Out of the 2342 transplants, 1487 (63.5%) transplants were performed in paediatric centres, 453 (19.3%) in centres for adults and 402 (17.2%) in combined centres. The number of children who underwent autologous HSCT (auto-HSCT) was 1053 (45%), whereas 1289 (55%) underwent allogeneic HSCT (allo-HSCT). Peripheral blood (PB) was the source of HSC in 751 (71.3%) out of 1053 auto-transplants, BM in 246 (23.4%) and PB+BM in 52 (4.9%) (missing data in 4, that is, 0.4%). Among the 1289 allo-transplants, BM was the source of HSC in 827 (64.3%), PB in 416 (32.3%), CB in 23 (1.8%) and BM+PB in 14 (1.1%) (missing data in 9, that is, 0.7%). Among them, 728 (57.4%) obtained HSC from MSD, 322 (25.4%) from UD, 195 (15.4%) from MMFD, 14 (1.1%) from CB family donor and 9 (0.7%) from CB unrelated donor (missing data in 21, that is, 1.6%). The number of children who underwent allo-HSCT for malignant diseases was 945 (73.4%), including ALL 376 (29.2%), AML 234 (18.2%), CML 177 (13.8%), MDS 97 (7.5%), NHL 35 (2.7%) and other malignancy 31 (2.4%), while 339 (26.9%) for non-malignant disorders, including SAA 202 (15.7%), immunodeficiencies 61 (4.7%), inborn errors of metabolism 40 (3.1%), Fanconi anaemia 19 (1.5%) and others 17 (1.3%). Out of 1053 recipients of auto-HSCT, 168 (16%) were transplanted for neuroblastoma, 129 (12.2%) for NHL, 124 (11.7%) for AML, 114 (10.8%) for ALL, 109 (10.4%) for Hodgkin's disease, 62 (5.9%) for Ewing's sarcoma, 16 (1.5%) for CNS tumour, 15 (1.4%) for Wilms tumour and 316 (30%) for other tumours. In 2001, the EBMT in collaboration with the European School of Haematology (ESH) developed the Outreach Programme, that is a programme supporting emerging HSCT projects and transplant centres in countries with limited resources and/or experience.

Twenty years of Polish experience with three consecutive protocols for treatment of childhood acute myelogenous leukemia.

Until 1983, results of treatment of acute myelogenous leukemia (AML) in Poland with different regimens were very poor. In 1983, the Polish Pediatric Leukemia/Lymphoma Study Group introduced a unified treatment protocol--a modified version of BFM-83 protocol. This led to an increase in the curability of AML from 15% to approximately 32%. In 1994, a modification was made: the high-risk patients (>5% blasts in bone marrow on day 15 of therapy and all M5 cases) received two additional cycles with intermediate-dose cytarabine (ID-ARAC). This led to a nonsignificant improvement in the 5-year event-free survival (EFS) rate from 32 to 36%. A new treatment protocol employing idarubicin in place of daunorubicin was introduced in 1998 and produced better initial responses, increase in the number of patients attaining remission after induction therapy and proportional increase of standard-risk patients. The probability of 5-year EFS (pEFS) for the whole group of patients increased from 36 to 47%. In standard- and high-risk groups, the 5-year pEFS was 62 and 33%, respectively. The probability of 5-year disease-free survival was 58% in the whole group, and there were no differences between risk groups. Unsatisfactory treatment results in children classified into the high-risk group are principally due to the low remission rate.

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.

Adoptive therapy with donor lymphocyte infusion after allogenic hematopoietic SCT in pediatric patients.

The aim of this study was to analyse the experience of Polish Pediatric Group for Hematopoietic Stem Cell Transplantation in respect to donor lymphocyte infusion procedure. The study included 51 pediatric patients with malignant (45) and non-malignant (6) diseases treated with DLI in the period 1993-2012. The indications for DLI were as follows: (1) increasing recipient chimerism after non-ablative hematopoietic SCT (18 patients); (2) immunomodulation after a reduced intensity conditioning regimen (2 patients); (3) increase in minimal residual disease detection (3 patients); and (4) relapse (28 patients). DLI was carried out at a median of 6 (0.5-79) months after SCT. DLI was administered as either a single-dose (in 19 cases) or in escalating-dose regimens (in 32 cases). The median total dose of CD3-positive T cells was 28.0 (0.1-730.0) × 10(6)/kg body weight. The time for assessment of DLI efficacy ranged from 0 to 70 (median 3) months. At evaluation, 18 patients experienced CR, 3 achieved PR, 19 showed relapse and 11 rejected the graft. DLI was found to be effective in 39% of cases. Complications of the procedure occurred in 18 patients; of these, 2 died. To sum up DLI shows efficacy in a significant percentage of children. Mortality related to the therapy adverse effects is low. However, this method requires standardization.

Prompt initiation of immunotherapy in children with an increasing number of autologous cells after allogeneic HCT can induce complete donor-type chimerism: a report of 14 children.

Immunotherapy consisting of withdrawal of immunosuppression and/or donor lymphocyte infusions was initiated in 14 children (10 acute lymphoblastic leukemia, three acute myeloblastic leukemia and one myelodysplastic syndrome) with an increasing amount of autologous DNA (increasing mixed chimerism, inMC) detected after allogeneic hematopoietic cell transplantation (HCT). Two children were in relapse when inMC was detected, 12 remained in CR. Children with overt relapse at the time of cessation of cyclosporine A (CsA) received "debulking" chemotherapy. One of them developed acute grade III graft-versus-host disease, converted to complete donor chimerism (CC) and achieved remission. Another patient did not respond and died due to disease progression. Among 12 children treated in remission, 11 responded with conversion to CC, seven after CsA withdrawal and four after DLI. One patient did not respond, rejected the graft and died due to pulmonary aspergillosis. In one patient, the response was transient, inMC reappeared and frank relapse occurred. One patient developed isolated CNS relapse despite conversion to CC, but achieved CR after conventional treatment. One child died in CC due to infection. No graft-versus-host disease (GvHD)-related death occurred. A total of 10 patients are alive in remission with median follow-up of 338 days. Our results support the hypothesis that chimerism-guided immunotherapy after alloHCT may prevent progression to hematological relapse.

The study of T-, B-, O- lymphocytes in acute lymphoblastic leukemia.

The T-, B-, and O-lymphocyte count changes were studied during the long-term intensive therapy of 43 ALL children. The control group consisted of 17 healthy children. The T-lymphocytes were identified by spontaneous formation of rosettes with sheep erythrocytes, the B-lymphocytes by EAC-rosette test. Patients were treated according to different program of multiple drug therapy and prophylactic cranial irradiation. During the study the applied therapeutic protocol produced the marked reduction of T- and B- lymphocytes. The decrease of B- lymphocytes was especially pronounced. The preliminary analysis suggests correlation between the reduction of T- and B- lymphocytes and prognosis.

The study of T-lymphocytes, granulocyte's phagocytic activity, and adherent cells in patients with acute lymphoblastic leukemia during levamisol therapy.

12 children with acute lymphoblastic leukemia remaining in remission for 1-3 years, were studied during levamisol therapy. T-lymphocytes count, phagocytic activity of granulocytes the adherent cell number were investigated. The clinical state of patients before, during and after levamisol treatment was evaluated. The increased resistance to infections after levamisol therapy was noted. The rise of T-lymphocyte and phagocyting granulocytes number was observed in 70% of patients after 6 weeks of therapy. At the same time the decrease of phagocytic index was found. No essential variations in adherent cells count were noted. The patients who did not respond to the levamisol treatment relapsed in 2-3 months.

Immunologic status of children with Hodgkin's disease (HD).

Concentration of serum immunoglobulins IgG, IgM, IgA, E-, EAC-rosette forming lymphocyte counts and phagocytic activity of granulocytes to Staphylococcus aureus were studied in venous blood of 12 children with HD and 15 normal controls during the combined long term radio- and polichemotherapy. The decrease in E- and EAC-rosette forming lymphocyte counts at diagnosis and during the combined radio- and chemotherapy single cycle and long-lasting treatment were found. The quantity of serum immunoglobulins IgA and IgM was above normal limits at diagnosis and decreased during 2 years of treatment. The impairment of phagocytic activity before treatment and during long term therapy was found. Analysis of the survival rate curves suggests the prognostic value of the initial T- and B-lymphocyte numbers in peripheral blood.

Immunological follow-up of non-Hodgkin's lymphoma (NHL) in children.

Concentrations of immunoglobulins IgG, IgM, IgA, E-, EAC-rosette forming lymphocyte counts and phagocytic function of granulocytes to Staphylococcus aureus were studied during the long-term polychemotherapy in 19 children with NHL and in the control group consisting of 15 healthy children. The decrease in levels of IgA and IgM, E and EAC rosetting lymphocyte counts following intensive long therapy was observed. No significant variations in immunoglobulin subclasses levels before and after single cytostatic cycle were found. The granulocyte phagocytic activity in NHL patients was above normal range. For evaluation of the prognostic value of NHL immunological classification survival rate curves were analyzed. It has been demonstrated that T-lymphoblasts proliferation is an unfavorable prognosis marker.

In vitro comparative antileukemic activity of various glucocorticoids in childhood acute leukemia.

Resistance to glucocorticoids is nowadays one of the strongest adverse risk factors in the treatment of childhood acute lymphoblastic leukemia (ALL). Differential in vitro antileukemic activity of various glucocorticoids and their cross-resistance pattern in childhood acute lymphoblastic and myeloblastic leukemia was determined by means of the MTT assay in 49 successfully tested samples of childhood acute leukemia. The equivalent antileukemic concentrations of respective drugs against lymphoblasts in de novo ALL samples were: 35 microM of hydrocortisone; 8 microM of prednisolone; 1.6 microM of methylprednisolone; 0.47 microM of dexamethasone and 0.23 microM of betamethasone. In comparison to initial ALL samples, the group of relapsed ALL was more resistant to: prednisolone (38-fold, p=0.004), dexamethasone (>32-fold, p=0.004), methylprednisolone (37-fold, p=0.039), betamethasone (38-fold, p=0.018) and hydrocortisone (33-fold, p=0.030). The group of acute myeloid leukemia (AML) samples were resistant to: prednisolone (>83-fold, p<0.001), dexamethasone (>32-fold, p<0.004), methylprednisolone (>65-fold, p=0.003), betamethasone (>66-fold, p=0.004) and hydrocortisone (61-fold, p=0.007), when compared to ALL at presentation. A significant cross-resistance between all used glucocorticoids as well as between glucocorticoids and other tested anti-leukemic drugs was found. In some individual cases in vitro glucocorticoid cross-resistance was less pronounced and relatively good antileukemic activity of betamethasone was observed.

Allogeneic hematopoietic cell transplantation from alternative donors in children with myelodysplastic syndrome: is that an alternative?

Allogeneic hematopoietic cell transplantation (HCT) in children with myelodysplastic syndrome (MDS) remains a challenge due to the toxic conditioning regimens administered to minimize the risk of relapse in the HLA-matched or of graft rejection in the HLA-mismatched settings. In the absence of matched sibling donors, alternative donors such as unrelated and/or partially matched family sources remain risky, yet the only available, options. Herein we report the results of HCT from alternative donors in 14 children with different subtypes of MDS (juvenile myelomonocytic leukemia [JMML] n = 9; myelodysplastic syndrome [MDS] refractory anemia n = 3; MDS refractory anemia with excess of blasts in transformation n = 2) transplanted at our institution. The median time from diagnosis to HCT was 9 months (range 4 to 90 months). The variety of HCT types included: unrelated peripheral blood progenitor cell transplantation (PBPCT) (n = 2), partially matched family donor T-cell-repleted BMT/PBPCT (n = 6), and haploidentical T-cell-depleted PBPCT (n = 6). Five of 14 patients remain alive at 7 to 37 months posttransplant (including two patients after partially matched family donor BMT, two patients after haploidentical T-cell-depleted-PBPCT, and one after unrelated-PBPCT, respectively). The major complications were: primary graft failure in the haploidentical T-cell-depleted-setting or graft-versus-host disease (GvHD) in T-cell-repleted partially matched family or unrelated settings, respectively. Despite the high transplant-related mortality rate in this series, allogeneic HCT from alternative donors remains an interesting solution for children with MDS who lack matched sibling donors. Due to improved immune reconstitution, despite an increased risk of GvHD, T-cell-repleted transplants from single HLA-mismatched family donors remain a valuable option for children without matched donors. Splenectomy prior to HCT may positively affect the posttransplant course in patients with overt splenomegaly for example those afflicted with JMML.

A prospective analysis of immune recovery in children following allogeneic transplantation of t-cell-depleted or non-T-cell-depleted hematopoietic cells from HLA-disparate family donors.

Transplantation of HLA-disparate hematopoietic stem cells from related donors is an alternative for the treatment of patients lacking an HLA-matched family or unrelated donor. In the cases of a single HLA antigen disparity, extensive T-cell depletion (TCD) is not required, yet antithymocyte globulin (ATG) must be administered to prevent GvHD or graft rejection. The major concern after HLA-mismatched transplants remains immune reconstitution. Therefore, we prospectively studied the recovery of lymphocyte subsets among 22 children transplanted from partially HLA-matched family donors. We compared two groups of patients: (1) the TCD group included children (n = 1.3) who received grafts after TCD (MACS) due to an HLA disparity for more than one antigen; (2) The non-TCD group included children with either one HLA-mismatched antigen, n = 7; or more than one disparate antigen (n = 2) who received T-cell-repleted grafts and ATG. The study demonstrated rapid NK cell reconstitution among the TCD group. TCD compromised T-cell reconstitution, thus preventing GvHD, but resulting in a higher incidence of severe infectious complications, graft rejection, and disease relapse. Increasing mixed chimerism required the application of donor T-cell addbacks, thus potentiating the risk of GvHD. Primary graft rejection occurred in eight children, who required further transplants. In the non-TCD group faster T-cell reconstitution (predominantly CD3+CD8+ cells) resulted in a lower rate of relapse and infection, yet a higher rate of GvHD, including two fatal cases. Due to improved immune reconstitution, in spite of an increased risk of GvHD, non-TCD transplants from single HLA-mismatched family donors remain a valuable option for children without matched donors.

Clinical value of the flow cytometric method for measuring lymphocyte subset activation: spontaneous activation of T-cell subpopulations is associated with acute GvHD.

Thymidine ((3)H-TdR) incorporation remains the most commonly used method to quantifying T-cell proliferation. This method, however, does not provide information about specific lymphocyte subpopulations responding to different stimuli. In our study, we modified previously described nonradioactive flow-cytometric T-cell activation assay measuring the expression of a CD69+ antigen on T-cell subsets and applied it to analysis of lymphocyte subsets activation/proliferation in children after allogeneic hematopoietic cell transplantation (HCT). We compared the percentage of spontaneously activated lymphocyte subpopulations (background) and the percentage of PHA-P, PWM, and SEB-stimulated cell subsets from two groups of patients: group 1, children with Graft versus Host Disease (GvHD) and group 2, children without any signs of GvHD at the time of analysis. High rate of spontaneous T-cell subset activation was found in group 1 with CD3+CD8+Ts cells being the most affected cell population. High background activation of Th and B cells correlated with the occurrence of autoimmune phenomena posttransplant. Rapid quantification of CD69+ expression on unstimulated and stimulated T-cell subsets proved to be a valuable method for monitoring children after allogeneic HCT. High proportion of activated, unstimulated Ts cells observed in the GvHD group may underline the critical role of CD3+CD8+ cells in the pathogenesis of GvHD. Thus in future immunosuppressive therapy may be adjusted according to the proportion of activated Ts cells.