Łukasz Sędek

The Immunophenotypes of Blast Cells in B-Cell Precursor Acute Lymphoblastic Leukemia: How Different Are They from Their Normal Counterparts?

Currently, there are three major maturational stages of CD19 antigen expressing B‐cell precursors (hematogones). In B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL), the malignant counterpart of hematogones, the leukemic blasts share common phenotypic features. The aim of the study was to enumerate the actual differences between the leukemic blasts in the CD10+ and CD10− subgroups of BCP‐ALL and hematogones by assessing the expression of the antigens: TdT, CD34, CD45, CD10, CD38, CD20 and CD22.

BCL11B, FLT3, NOTCH1 and FBXW7 mutation status in T-cell acute lymphoblastic leukemia patients.

T-cell acute lymphoblastic leukemia is a heterogeneous malignancy originating from developing lymphocyte precursors likely due to mutations in genes regulating thymocyte differentiation. Here, we characterized mutation status of BCL11B and FLT3 genes, presumably involved in T-ALL, together with FBXW7 and NOTCH1 as known players in T-ALL in 65 pediatric T-cell acute lymphoblastic leukemia patients. We also aimed at the assessment of prognostic value of NOTCH1 and FBXW7 mutations in ALL-IC BFM 2002 protocol. FLT3 and BCL11B mutations were detected in 3% and 2% of patients, respectively. FBXW7 mutations were observed in 8% of patients, while NOTCH1 was mutated in 40%. No correlation was found between NOTCH1 and FBXW7 mutations and traditionally used clinical factors or molecular features. In total we have detected nine mutations, which have not been previously described by others. Eight of them were found in NOTCH1 and one in BCL11B gene. Observed frequencies of NOTCH1 and FBXW7 are in line with previous reports, thus confirming postulated participation of these two genes in T-ALL pathomechanism. Moreover, we report on mutation frequency of FLT3 and BCL11B, not extensively studied in T-ALL so far. Finally, we suggest a putative role of BLC11B as an oncogene in T-ALL pathogenesis.

Infant acute bilineal leukemia

Most cases of acute leukemia can be assigned to the myeloid, B or T lineage. There are rare cases of acute leukemia, which cannot be clearly classified, because either blasts express antigens of more than one lineage (acute biphenotypic leukemias) or distinct blast populations of two lineages co-exist (acute bilineal leukemias, aBLL). We present a 10-month-old infant with de novo aBLL, characterized by blasts of monocytic and B-cell precursor lineages. All leukemic cells harbored identical complex MLL gene rearrangement. Despite poor initial response, both to acute lymphoblastic leukemia (ALL) induction treatment and acute myeloid leukemia induction blocks, the child reached complete clinical remission with minimal residual disease negative status and was transplanted. Unfortunately, 16 months from HSCT the patient experienced BM relapse with all blasts characterized by pro-B-ALL immunophenotype. This case report illustrates that aBLL is a very aggressive type of acute leukemia that should be individually treated and monitored, particularly in children less than 1 year of age.

Is there an impact of treatment with DPP-4 inhibitors on lymphocyte subpopulations in type 2 diabetic patients?

INTRODUCTION Dipeptidil peptidase 4 inhibitors (DPP-4) are a group of antihyperglycemic agents. DPP-4 is an enzyme expressed on lymphocyte surface as co-stimulatory molecule in activation processes. The aim was to assess lymphocyte subpopulations initially and after 14 days of treatment with DPP-4 inhibitors sitagliptin, saxagliptin and vildagliptin. MATERIAL AND METHODS The study was conducted in three groups 10 subjects each, of type 2 diabetic patients. In subjects studied an initial tests followed by repeated ones after 14 days of treatment with sitagliptin, saxagliptin, and vildagliptin in therapeutic doses were performed. Baseline test as well as lymphocyte subpopulations (total T cells, and T-cell subsets CD4+, CD8+, CD26+, CD45RA+, CD45RO+, CD4+/CD25+) using 7-colour flow cytometry method were performed. RESULTS In patients receiving sitagliptin no significant increase in lymphocyte subpopulations were observed. In patients who received vildagliptin significant increase of total T-cells (p < 0.05); in patients treated with saxagliptin significant (p < 0.05) though mild increased percentage of total T-cells and CD4+, CD26+, CD45RO+ subsets were found. CONCLUSIONS The study showed mild but significant increase of several T-cell subsets after treatment with saxagliptin and vildagliptin with non significant elevation after treatment with sitagliptin. It seems that changes are not expressed enough to have a clinical impact.

Subpopulacje limfocytów T i komórek NK we krwi obwodowej u zdrowych dzieci w wieku 3–19 lat

Streszczenie Wstep Ocena poszczegolnych subpopulacji komorek linii limfocytarnej krwi obwodowej ma istotne znaczenie w diagnostyce wielu zaburzen u dzieci. Analiza wynikow i mozliwośc oceny zmian w ukladzie limfoidalnym wymaga znajomości wartości odsetkowych i liczbowych poszczegolnych linii limfocytow określonych dla zdrowej populacji. Cel Celem aktualnej pracy bylo dokladne określenie wartości odsetkowych oraz bezwzglednych komorek ukladu limfoidalnego (subpopulacje linii limfocytow T i NK) we krwi obwodowej w populacji dzieci zdrowych. Material i metoda Badania wykonano za pomocą 6-kolorowej cytometrii przeplywowej u 40 zdrowych dzieci w wieku 3–19 lat. Wyniki Przedstawione w niniejszym opracowaniu mogą posluzyc jako odniesienie do celow kontrolno-porownawczych dla wynikow pacjentow z zaburzeniami w ukladzie immunologicznym w przebiegu roznego typu schorzen. Jest to pierwsza w Polsce publikacja w tak szeroki sposob określająca rozklad wybranych subpopulacji komorek jednojądrzastych krwi obwodowej u dzieci.

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.

Assessment of selected B cells populations in the workers of X-ray departments

ObjectivesWorkers of X-ray departments are occupationally exposed to long-term low levels of ionizing radiation (LLIR), which may affect their humoral immunity. The aim of the study was to assess the influence of LLIR on the number and proportion of B cells (CD19+), B1 cells (CD5+CD19+) and memory B cells (CD27+CD19+) in peripheral blood of such workers.Materials and MethodsIn the study group of 47 X-ray departments workers and the control group consisting of 38 persons, the number and percentage of CD19+, CD5+CD19+, CD27+CD19+ cells as well as CD5+CD19+/CD19+ and CD27+CD19+/CD19+ cell ratios were assessed using flow cytometry. Additionally, the study group was divided into 2 groups by the length of employment below and over 15 years and analysis adjusted for age and smoking habit was performed.ResultsThe total number of CD19+ cells showed significant increase in the group of workers in comparison with the persons from the control group, whereas the percentage of CD5+CD19+ cells as well as CD27+CD19+/CD19+ and CD5+CD19+/CD19+ cell ratios were lower. Percentage, number of CD5+CD19+ cells and CD5+CD19+/CD19+ cell ratio were significantly lower in the workers with length of employment longer than 15 years in comparison with those employed below 15 years. Moreover, we found positive associations between the number of CD19+ cells and employment as well as smoking habit, whereas the number of CD5+CD19+ cells was positively associated with cigarette smoking alone. Percentage of CD5+CD19+ cells as well as CD5+CD19+/CD19+ and CD27+CD19+/CD19+ cell ratios were negatively correlated with employment.ConclusionsThe study suggests association between the suppressive influence of low level ionizing radiation on circulating in peripheral blood, especially of B1 cells as well as of memory B cells, in workers of X-ray units, which is adverse in relation to microbiological threat.

Ekspresja receptorów dla chemokin na subpopulacjach limfocytów T we krwi obwodowej u zdrowych dzieci

Streszczenie Uklad chemokiny–receptory odgrywa zasadniczą role w calej embriogenezie, reguluje takze procesy wrodzonej i nabytej odporności, co prowadzi do wytworzenia prawidlowej odpowiedzi immunologicznej. Analiza wynikow i mozliwo ści oceny zmian w ukladzie limfoidalnym wymaga znajomości wartości odsetkowych i liczbowych poszczegolnych linii limfocytow określonych dla zdrowej populacji. Cel Celem aktualnej pracy bylo dokladne określenie wartości odsetkowych oraz bezwzglednych antygenow powierzchniowych limfocytow T, bedących receptorami dla wybranych chemokin, we krwi obwodowej w populacji dzieci zdrowych, przy wykorzystaniu wielokolorowej cytometrii przeplywowej, a takze porownanie uzyskanych wartości w badanej grupie z uwzglednieniem plci i wieku. Wyniki Wyniki przedstawione w niniejszej pracy mogą posluzyc jako odniesienie do wynikow uzyskanych u pacjentow z zaburzeniami ukladu immunologicznego w przebiegu roznych schorzen. Jest to pierwsza w Polsce publikacja w tak szeroki sposob określająca rozklad subpopulacji limfocytow T krwi obwodowej u dzieci z receptorami dla wybranych chemokin.

Cost-effective screening of DNMT3A coding sequence identifies somatic mutation in pediatric T-cell acute lymphoblastic leukemia

In pediatric T‐cell acute lymphoblastic leukemia (T‐ALL), risk assignment schemes preclude reliable prediction of outcome, and thus, new prognostic factors are needed. Mutations in DNMT3A are candidate prognostic and classification markers in adults with acute myeloid leukemia (AML) and T‐ALL and thus were considered as candidates prognostic markers in pediatric T‐ALL.

Expression of Chemokine Receptors on Peripheral Blood T Cells in Children with Chronic Kidney Disease

Chemokine receptors play a role in leukocyte recruitment, activation, and maintaining effector functions and regulate adaptive immune response and angiogenesis. The study aimed at flow cytometric analysis of T cell subsets with selected surface chemokine receptors (CCR4, CCR5, CCR7, CXCR3, and CXCR4) or receptor combination in peripheral blood of children with chronic kidney disease (CKD) on hemodialysis (HD). The percentage of T lymphocytes with CD8 and combined CD28,CCR7 expression was higher in HD children. The percentage of T lymphocytes expressing CCR7, CD28,CCR7, and CXCR4,CD8 was increased in children on conservative treatment. Total number (tn) of CXCR4+ cells was reduced in children on hemodialysis. The tn of T CXCR3+ cells was lower in children on conservative treatment. During HD the percentage of T CD4+ cells was higher and of T CXCR3+ lymphocytes was lower after HD session as compared to 15 min of session duration. During HD tn of T cells with expression of CCR4, CCR5, CCR7, CXCR3, and CXCR4 was constant. The alteration of chemokine receptors expression in children with CKD occurs early in the development. Diminished expression of CXCR3, CXCR4 on T cells in patients with CKD on HD might result in impaired inflammatory response. Increased CCR7+ T cell percentage could be responsible for the alteration of migration of cells into secondary lymphatic organs.