Analysis of Peripheral Blood Mononuclear Cells Gene Expression Highlights the Role of Extracellular Vesicles in the Immune Response following Hematopoietic Stem Cell Transplantation in Children

Hematopoietic stem cell transplantation (HSCT) is an effective treatment method used in many neoplastic and non-neoplastic diseases that affect the bone marrow, blood cells, and immune system. The procedure is associated with a risk of adverse events, mostly related to the immune response after transplantation. The aim of our research was to identify genes, processes and cellular entities involved in the variety of changes occurring after allogeneic HSCT in children by performing a whole genome expression assessment together with pathway enrichment analysis. We conducted a prospective study of 27 patients (aged 1.5–18 years) qualified for allogenic HSCT. Blood samples were obtained before HSCT and 6 months after the procedure. Microarrays were used to analyze gene expressions in peripheral blood mononuclear cells. This was followed by Gene Ontology (GO) functional enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein–protein interaction (PPI) analysis using bioinformatic tools. We found 139 differentially expressed genes (DEGs) of which 91 were upregulated and 48 were downregulated. “Blood microparticle”, “extracellular exosome”, “B-cell receptor signaling pathway”, “complement activation” and “antigen binding” were among GO terms found to be significantly enriched. The PPI analysis identified 16 hub genes. Our results provide insight into a broad spectrum of epigenetic changes that occur after HSCT. In particular, they further highlight the importance of extracellular vesicles (exosomes and microparticles) in the post-HSCT immune response.

The Expression of Genes Related to Lipid Metabolism and Metabolic Disorders in Children before and after Hematopoietic Stem Cell Transplantation-A Prospective Observational Study

Metabolic disorders in children after hematopoietic stem cell transplantation (HSCT) are poorly characterized. However, it is known that dyslipidemia and insulin resistance are particularly common in these patients. We conducted a prospective study of 27 patients treated with HSCT to assess the possibility of predicting these abnormalities. We measured gene expressions using a microarray technique to identify differences in expression of genes associated with lipid metabolism before and after HSCT. In patients treated with HSCT, total cholesterol levels were significantly higher after the procedure compared with the values before HSCT. Microarray analysis revealed statistically significant differences in expressions of three genes, DPP4, PLAG1, and SCD, after applying the Benjamini-Hochberg procedure (pBH < 0.05). In multiple logistic regression, the increase of DPP4 gene expression before HCST (as well as its change between pre- and post-HSCT status) was associated with dyslipidemia. In children treated with HSCT, the burden of lipid disorders in short-term follow-up seems to be lower than before the procedure. The expression pattern of DPP4 is linked with dyslipidemia after the transplantation.

Comparison of blood pressure values and expression of genes associated with hypertension in children before and after hematopoietic cell transplantation

Hypertension is a well-known late effect of hematopoietic cell transplantation (HCT), but no markers predicting its development are known. Our aim was to assess short-term blood pressure (BP) values and expressions of hypertension-associated genes as possible markers of hypertension in children treated with HCT. We measured systolic blood pressure (SBP) and diastolic blood pressure (DBP), using both office procedure and ambulatory BP monitoring (ABPM) in children before HCT and after a median of 6 months after HCT. We compared the results with two control groups, one of healthy children and another of children with simple obesity. We also performed microarray analysis of hypertension-associated genes in patients treated with HCT and children with obesity. We found no significant differences in SBP and DBP in patients before and after HCT. We found significant differences in expressions of certain genes in patients treated with HCT compared with children with obesity. We concluded that BP values in short-term follow-up after HCT do not seem to be useful predictors of hypertension as a late effect of HCT. However, over expressions of certain hypertension-associated genes might be used as markers of hypertension as a late effect of HCT if this is confirmed in larger long-term studies.

Gastrointestinal peptides in children before and after hematopoietic stem cell transplantation

BACKGROUND

Gastrointestinal tract function and it's integrity are controlled by a number of peptides whose secretion is influenced by severe inflammation. In stomach the main regulatory peptide is ghrelin. For upper small intestine cholecystokinin and lower small intestine glucagon-like peptide- 1 are secreted, while fibroblast growth factor-21 is secreted by several organs, including the liver, pancreas, and adipose tissue [12]. Hematopoietic stem cell transplantation causes serious mucosal damage, which can reflect on this peptides.

METHODS

The aim of the study was to determine fasting plasma concentrations of ghrelin, cholecystokinin, glucagon- like peptide-1, and fibroblast growth factor-21, and their gene expressions, before and 6 months after hematopoietic stem cell transplantation.27 children were studied, control group included 26 healthy children.

RESULTS

Acute graft versus host disease was diagnosed in 11 patients (41%, n = 27). Median pre-transplantation concentrations of gastrointestinal peptides, as well as their gene expressions, were significantly lower in studied group compared with the control group. Only median of fibroblast growth factor-21 concentration was near-significantly higher before stem cell transplantation than in the control group. The post-hematopoietic transplant results revealed significantly higher concentrations of the studied peptides (except fibroblast growth factor-21) and respective gene expressions as compare to pre transplant results. Median glucagone like peptide-1 concentrations were significantly decreased in patients with features of acute graft versus host disease. Moreover, negative correlation between glucagone like peptide-1 concentrations and acute graft versus host disease severity was found.

CONCLUSIONS

Increased concentrations and gene expressions of gastrointestinal tract regulation peptides can be caused by stimulation of regeneration in the severe injured organ. Measurement of these parameters may be a useful method of assessment of severity of gastrointestinal tract complications of hematopoietic stem cell transplantation.

Outcome of acute lymphoblastic leukemia in children with down syndrome-Polish pediatric leukemia and lymphoma study group report

Children with Down syndrome (DS) have a 20-fold increased risk of developing leukemia compared with the general population. The aim of the study was to analyze the outcome of patients diagnosed with Down syndrome and acute lymphoblastic leukemia (ALL) in Poland between the years 2003 and 2010. A total of 1848 children were diagnosed with ALL (810 females and 1038 males). Of those, 41 (2.2%) had DS. The children were classified into three risk groups: a standard-risk group-14 patients, an intermediate-risk group-24, a high-risk group-3. All patients were treated according to ALLIC 2002 protocol. The median observation time of all patients was 6.1 years, and in patients with DS 5.3 years. Five-year overall survival (OS) was the same in all patients (86% vs 86%, long-rank test, p = .9). The relapse-free survival (RFS) was calculated as 73% in patients with DS and 81% in patients without DS during a median observation time (long-rank test, p = .3). No statistically significant differences were found in the incidence of nonrelapse mortality between those two groups of patients (p = .72). The study was based on children with ALL and Down syndrome who were treated with an identical therapy schedule as ALL patients without DS, according to risk group. This fact can increase the value of the presented results.

Influence of PM1 and PM2.5 on lung function parameters in healthy schoolchildren-a panel study

To evaluate lung function responses to short-term indoor PM₁ and PM_2.5 concentrations, we conducted a panel study of healthy schoolchildren aged 13-14 years. The following lung function parameters FVC, FEV₁, PEF, and mid expiratory flows MEF₂₅, MEF₅₀, and MEF₇₅ were measured in 141 schoolchildren of the secondary school in Wroclaw, Poland in years 2009-2010. On days when spirometry tests were conducted, simultaneously, PM₁ and PM_2.5 samples were collected inside the school premises. Information about differentiating factors for children including smoking parents, sex, living close to busy streets, dust, mold, and pollen allergies were collected by means of questionnaires. To account for repeated measurements, the method of generalized estimating equations (GEE) was used. The GEE models for the entire group of children revealed the adverse effects (p < 0.05) of PM₁ and PM_2.5. Small differences in effects estimates per interquartile range (IQR) of PM₁ and PM_2.5 on MEF₂₅ (5.1 and 4.8 %), MEF₅₀ (3.7 and 3.9 %), MEF₇₅ (3.5 and 3.6 %) and FEV₁ (1.3 and 1.0 %) imply that PM₁ was likely the component of PM_2.5 that might have a principal health effect on these lung function parameters. However, the reduction of FVC and PEF per IQR for PM_2.5 (2.1 and 5.2 %, respectively) was higher than for PM₁ (1.0 and 4.4 %, respectively). Adjustment for potential confounders did not change the unadjusted analysis.

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.

[Genotyping and minimal residual disease study in children with acute myeloid leukemia: preliminary results]

The aim of the paper is to present the initial results of molecular examination which was started in 2006 for children with acute myeloid leukemia. Better knowledge of biology of this disease, can result in establishing of new risk factors what allows more precise patient stratification to different therapeutic groups. Study was obtained patients until to 18 years of age treated according to AML-BFM 2004 INTERIM protocol in 14 centers of the Polish Pediatric Leukemia/Lymphoma Study Group. Mononuclear cells were collected from bone marrow on time points established according to the AML-BFM 2004 INTERIM protocol. Collected cells were isolated on Ficoll gradient, and RNA and DNA were isolated using TRIZOL reagent. To synthesize cDNA an amount of 1 mg of total RNA was used. To perform quantitative RT-PCR and RQ-PCR reactions 4 fusion gene transcripts (AML1-ETO, CBFb-MYH11, PML-RARA /subtype bcrl and bcr3/) were used according to the protocol established by Europe Against Cancer Program. An expression of WT1 gene was tested additionally. An analysis of ABL control gene was used to normalize of achieved results. Determination of duplication of FLT3 gene in DNA sample was performed with starters complementary to JM region. Genotyping was performed in 75 patients with acute myeloid leukemia so far. AML1-ETO fusion gene transcript was found in 14 patients (19%). PML-RARA (subtype bcr3) and CBFB-MYH11 gene transcripts were detected in 3 (4%) and 3 (4%) patients, respectively. Duplication of FLT3 gene was found in 4 (5.3%) cases. Between 67 tested children over expression of WT1 was present in 51 patients (76%). Analysis of MRD level in subsequent time points showed systematic decrease of number of fusion gene transcript copies and gene WT1 expression. To establish the rate of molecular marker presence in AML in children and the influence of the presence of MRD on the treatment results as well, the study has to be conducted on a larger group of patients with longer follow-up.

[Central nervous system involvement at diagnosis and at relapse in children with neuroblastoma]

Central nervous system (CNS) involvement in the course of neuroblastoma (NBL) in children is relatively rare. However, it seems to become serious clinical problem in the group of patients from high risk group. They presently achieve longer time of survival caused by employment of more intensive treatment modalities. The aim of the study was clinical evaluation of the patients over 1 year of age with stage 4 NBL with CNS involvement, both at diagnosis and at relapse. From 1997 to 2007, 117 patients (age 0.2-13.5 years) started NBL treatment. In 58 children over 1 year, stage 4 of disease was diagnosed. In 4 (6.9%) cases the CNS involvement was found at diagnosis. In 5 patients (8.6%) the isolated relapse in brain was diagnosed. The clinical symptoms caused by increased intracranial pressure were observed in all patients at relapse. In the case of initial involvement no neurological symptoms were observed. All 5 children with CNS involvement as isolated relapse did not present with infiltration of skull bones, whereas at initial diagnosis the brain lesions were continuous with bone metastases. Among 5 patients with isolated relapse 4 died because of NBL progression. Among 4 children with initial CNS involvement 1 died due to haemorrhage to CNS. Probably brain involvement at initial NBL diagnosis is not an additional negative prognostic factor. Because of extremely poor prognosis in patients with CNS relapse it should be advised to consider possible implementation of preventive treatment. It is also necessary to invent new more effective treatment methods.

[Long-term observations of children with acute lymphoblastic leukemia and high leukocytosis treated according to modified "New York" protocols (1987-2003)]

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Due to new therapeutic schedules and cooperation between oncological centers it is curable in more than 80% of affected children. For the optimalization of the therapy there is necessary to assess the risk criteria that have influence on the treatment results in the certain groups of patients. Hyperleukocytosis and the age (less than 1 year and more than 10 years) are known as unfavorable risk factors. The study was designed to assess the long-term treatment results in children with ALL and the initial leukocytosis over 50 000/mm3 with the use of the modified "New York" protocols. We present the treatment results of 340 children with ALL treated in nine centers of Polish Pediatric Leukemia/Lymphoma Study Group (PPLLSG) according to three consecutive versions of modified "New York" protocol (group I, II, and III) between 1987 and 2003. Within the analyzed groups the first complete remission (I CR) was achieved in 91%, 95% and 96% of the patients, respectively. Relapses occurred in 37%, 21.5% and 26% of the patients and 3.7%, 1.8% and 5.7% of children died in the I CR due to complications, in the I, II and III therapeutic group, respectively. Obtained 5-and 10-year event-free survival (EFS) were 56% and 53.5% for the group I and 73% and 73% for the group II. Five-year EFS for the group III was 67%. The implementation of the New York protocol in 1987 and New York I in 1997 has improved the treatment results in children with ALL and initial leukocytosis over 50 000/mm3. Protocol New York II did not further improve the treatment results. Among analyzed parameters (age, gender, the initial leukocytosis, the blast cells immunophenotype) only age had the statistical significance. The implementation of modified "New York" protocols has improved the treatment results in children with ALL and initial leukocytosis over 50 000/mm3 compared to previous results.