Katarzyna Pawelec

Standard and intermediate risk acute lymphoblastic leukemia in Poland: A report of the Polish Children's Leukemia/Lymphoma Study Group

A total of 527 children with acute lymphoblastic leukaemia (ALL) from the most frequent risk groups: standard risk group (SRG) and intermediate risk group (IRG) were treated between 1987 and 1991 according to an intensified treatment program (based on the BFM protocol) including the use of an intermediate dose of methotrexate in the IRG. A comparison of the treatment results in this group from 513 children treated between 1981 and 1987 indicates that the chance for a 6 year event‐free survival has increased to 73% (previously 55%).

The Influence of Primary Cytomegalovirus or Epstein-Barr Virus Infection on the Course of Idiopathic Thrombocytopenic Purpura

Idiopathic thrombocytopenic purpura (ITP) in children is usually triggered by a viral infections such as cytomegalovirus (CMV) or Epstein-Barr virus (EBV) infection. The aim of this study was to assess the frequency of CMV and EBV infections in children with first relapse of ITP, and the influence of these infections on the course and response to treatment of ITP. Sixty patients (30 boys and 30 girls) with ITP were enrolled into the study. We found that the age at the onset of ITP was from 1 month to 17 years (mean 7.0 ± 5.7 years), the platelet number was from 1 to 79 x 10(9)/L (mean 18.1 ± 19.0 x 10(9)/L) at the time of diagnosis and it increased from 17 to 395 x 10(9)/L (mean 134.4 ± 81.2 x 10(9)/L)(p < 0.05) after the first course of therapy. Forty seven patients required pharmacological treatment, the duration of the treatment was from 2 to 25 days (mean 6.1 ± 4.1 days). Relapses were observed in 27 (45%) of the patients. Active CMV infection was found in 19 patients (31.7%), EBV infection in 5 patients (8.3%), and both infections concomitantly in 1 patient (1.7%). The group of patients with CMV or EBV infection(n = 25) did not differ from the patients free of infection (n = 35) in regard to the age, number of platelets at onset, duration of treatment, number of platelets after treatment, number of relapses, and the interval between the onset and first relapse. In conclusion, active CMV or EBV infection is common in children with ITP. These infections do not seem to have an appreciable bearing on the clinical course and the response to treatment on children with ITP.

Influence of Iron Overload on Immunosuppressive Therapy in Children with Severe Aplastic Anemia

Children with severe aplastic anemia (AA) require multiple transfusions of the red blood cells during the immunosuppressive therapy. This leads to iron overload and manifests as elevated levels of ferritin in blood. The aim of this study was a retrospective analysis of the influence of the elevated serum ferritin on the overall survival, event-free survival, the risk of relapse, and response to treatment in children with AA during immunosuppressive therapy. We analyzed 38 children with AA (19 girls, 19 boys, aged 2-17 years) treated according to the obligatory protocol for AA in Poland. The response rate was assessed on days 84, 112, and 360. Patients were divided into three groups: group I consisted of children with ferritin below 285 ng/mL (6 children), group II with ferritin between 286 and 1,000 ng/mL (13 children), and group III ferritin>1,000 ng/mL (19 children). Kaplan-Meier plot was used to estimate the overall survival and event-free survival. We found the overall survival did not differ between the three groups. Event-free survival was significantly shorter (p=0.03) in patients with ferritin levels>1,000 ng/mL compared with the groups with ferritin bellow 1,000 ng/mL. The time to relapse was significantly shorter in group III than in the other two groups (p=0.02). We also found the differences in the treatment response at day 84 (p=0.03) and day 112 (p<0.0001) of immunosuppressive therapy. These findings confirm a negative influence of iron overload in children with AA on the effect of treatment and the risk of relapse.

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.

Stem Cell Experiments Moves into Clinic: New Hope for Children with Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease with long-term complications that affects mainly preterm born children with low birth weights, especially those treated with mechanical ventilation and oxygen therapy. Successful treatment of BPD could reduce the incidence of other diseases of prematurity such as periventricular leukomalacia and retinopathy. The effects of current therapies are unsatisfactory; thus, searching for novel therapeutic is underway. One promising approach seems administration of mesenchymal stem cells (MSC). Preclinical data strongly support the role of progenitor cells in the preservation of lung structure. MSC can be found more often in pre-term than term umbilical cord and its isolation from Whartons jelly carries a potential in treating diseases of prematurity. Several questions concerning the use of MSC in BPD remain to be answered, including the amount of transferred cells, intervals between infusions, the best route for administration and the timing. MSC can be administered as a treatment or prophylaxis. However, having in mind that not all prematurely born children are at risk of developing bronchopulmonary dysplasia, a search for laboratory markers identifying potential patients should be conducted. This review summarizes the latest achievements in MSC therapy in the context of BPD.

Association of germline genetic variants in RFC, IL15 and VDR genes with minimal residual disease in pediatric B-cell precursor ALL

Minimal residual disease (MRD) enables reliable assessment of risk in acute lymphoblastic leukemia (ALL). However, little is known on association between MRD status and germline genetic variation. We examined 159 Caucasian (Slavic) patients with pediatric ALL, treated according to ALL-IC-BFM 2002/2009 protocols, in search for association between 23 germline polymorphisms and MRD status at day 15, day 33 and week 12, with adjustment for MRD-associated clinical covariates. Three variants were significantly associated with MRD: rs1544410 in VDR (MRD-day15); rs1051266 in RFC (MRD-day33, MRD-week12), independently and in an additive effect with rs10519613 in IL15 (MRD-day33). The risk alleles for MRD-positivity were: A allele of VDR (OR = 2.37, 95%CI = 1.07–5.21, P = 0.03, MRD-day15); A of RFC (OR = 1.93, 95%CI = 1.05–3.52, P = 0.03, MRD-day33 and MRD-week12, P < 0.01); A of IL15 (OR = 2.30, 95%CI = 1.02–5.18, P = 0.04, MRD-day33). The risk for MRD-day33-positive status was higher in patients with risk alleles in both RFC and IL15 loci than in patients with risk alleles in one locus or no risk alleles: 2 vs. 1 (OR = 3.94, 95% CI = 1.28–12.11, P = 0.024), 2 vs. 0 (OR = 6.75, 95% CI = 1.61–28.39, P = 0.012). Germline variation in genes related to pharmacokinetics/pharmacodynamics of anti-leukemic drugs and to anti-tumor immunity of the host is associated with MRD status and might help improve risk assessment in ALL.

Central nervous system haemorrhage causing early death in acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APL) is a rare type of paediatric leukaemia characterised by a specific genetic mutation and life-threatening coagulopathy. The discovery of all-trans retinoic acid (ATRA), which acts directly on promyelocytic locus-retinoic acid receptor α (PML-RARα) gene product, brought a revolution to the therapy of this disorder. Unfortunately, despite an improvement in the complete remission rate, the early death (ED) rate has not changed significantly, and the haemorrhages remain a major problem. The most common bleeding site, which accounts for about 65-80% of haemorrhages, is the central nervous system. Second in line are pulmonary haemorrhages (32%), while gastrointestinal bleedings are relatively rare. Haemorrhages result from thrombocytopaenia, disseminated intravascular coagulopathy (DIC), and systemic fibrinolysis. Herein we present a boy aged one year and nine months with APL. The patient was not eligible for ATRA administration due to poor clinical condition. He developed bleeding diathesis that presented as disseminated intravascular coagulation (DIC) and led to intracranial haemorrhage, which resulted in the patients death.

Imatinib in the treatment of chronic myeloid leukemia in children and adolescents is effective and well tolerated: Report of the Polish Pediatric Study Group for the Treatment of Leukemias and Lymphomas

BACKGROUND Chronic myeloid leukemia (CML) constitutes only 2-3% of all leukemias in pediatric patients. Philapelphia chromosome and BCR-ABL fusion are genetic hallmarks of CML, and their presence is crucial for targeted molecular therapy with tyrosine kinase inhibitors (TKIs), which replaced hematopoietic stem cell transplantation (HSCT) as a standard first-line therapy. The disease in pediatric population is rare, and despite molecular and clinical similarities to CML in adults, different approach is needed, due to the long lifetime expectancy and distinct developmental characteristics of affected children. OBJECTIVES The objective of this study is to evaluate treatment with imatinib in Polish pediatric patients with CML. MATERIAL AND METHODS We analyzed the results of treatment with imatinib in 57 pediatric patients (June 2006 - January 2016) from 14 Polish pediatric hematology and oncology centers. RESULTS In the study group, 40 patients continued imatinib (median follow-up: 23.4 months), while in 17 the treatment was terminated (median follow-up: 15.1 months) due to therapy failure. In the latter group, 13 patients underwent HSCT, while 4 switched to second-generation TKIs. The 5-year overall survival rate (OS) in the study group was 96%, and the 5-year event-free survival (EFS) was 81%. CONCLUSIONS Our results confirm that the introduction of TKI therapy has revolutionized the treatment of CML in the pediatric population by replacing the previous method of treatment with HSCT and allowing a high percentage of OS and EFS.

Infectious mononucleosis-like syndrome with high lymphocytosis and positive IgM EBV and CMV antibodies in a three-year-old girl

Primary Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection usually affects preadolescent children or young adults, causing similar clinical presentation. Signs and symptoms are typically mild, and the majority of clinical and laboratory findings resolve spontaneously within one month after onset. In adulthood, the risk of fulminant EBV infection and severe complications is much higher, which may be related to increasing memory CD8+ T-cell population with age. It is still not clear what exactly triggers T-cell clonal proliferation. Animals model studies on heterologous immunity between viruses revealed that pre-existing memory T-cells may contribute to excessive immune response during subsequent infection with a new, unrelated pathogen. A 3.5-year-old girl was admitted to hospital with a suspicion of lymphoproliferative disorder. Peripheral blood smear revealed a massive lymphocytosis (61,600 cells/µl) with 62% share of atypical lymphocytes. The clinical presentation and positive EBV and CMV IgM test strongly suggested infectious mononucleosis syndrome as a result of EBV and CMV coinfection.

The Potential of Wharton’s Jelly Derived Mesenchymal Stem Cells in Treating Patients with Cystic Fibrosis

Cystic fibrosis (CF) is a life-threatening autosomal recessive multi-organ disorder with the mean incidence of 0.737 per 10,000 people worldwide. Despite many advances in therapy, patients fail to have a satisfactory quality of life. The end-stage lung disease still accounts for significant mortality and puts patients in the need of lung transplantation. Even though the disease is monogenic, the trials of topical gene transfer into airway epithelial cells have so far been disappointing. It is proven that stem cells can be differentiated into type II alveolar epithelial cells. Whartons jelly-derived mesenchymal stem cells (MSC) from non-CF carrier third-party donors could be an effective alternative to bone marrow or embryonic stem cells. The harvesting process is an easy and ethically uncontroversial procedure. The MSC cell should be applied through repetitive infusions due to rapid lung epithelial cell turnover. However, the low stem cell incorporation remains a problem. Pre-clinical studies imply that even 6-10% of the wild-type cystic fibrosis transmembrane conductance regulator (CFTR) expression could be enough to restore chloride secretion. The route of administration, the optimal dose, as well as the intervals between infusions have yet to be determined. This review discusses the clinical potential of mesenchymal stem cell in CF patients.