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Biomedical subjects

George Paterakis

Publications and source records attributed to George Paterakis.

13 recordsLinked to original sources
PubMed2007

T-cell acute lymphoblastic leukemia relapsing as acute myelogenous leukemia.

We present the unusual case of a 16-year-old girl with T-cell acute lymphoblastic leukemia (ALL) with an early thymocyte immunophenotype without myeloid markers, who after 13 months of complete hematological remission relapsed as acute myelogenous leukemia (AML) with minimal differentiation and died of her disease. Whether the AML represented a relapse with lineage switch of the original immature T-cell clone or a new secondary malignancy, could not be proven due to the absence of molecular or clonal markers. This report suggests that a subset of CD7+ T-cell leukemias without mature T-cell antigens (CD4-, CD8-) are minimally differentiated and can relapse as AML.

Acute Disease↗
PubMed2006

Intracoronary infusion of CD133+ and CD133-CD34+ selected autologous bone marrow progenitor cells in patients with chronic ischemic cardiomyopathy: cell isolation, adherence to the infarcted area, and body distribution.

Central issues in intracoronary infusion (ICI) of bone marrow (BM)-cells to damaged myocardium for improving cardiac function are the cell number that is feasible and safe to be administrated as well as the retention of cells in the target area. Our study addressed these issues in eight patients with chronic ischemic cardiomyopathy undergoing ICI of selected BM-progenitors. We could immunomagnetically isolate 0.8 +/- 0.32 x 10(7) CD133(+) cells and 0.75 +/- 0.24 x 10(7) CD133(-)CD34(+) cells from 310 +/- 40 ml BM. After labeling these cells with (99m)Tc-hexamethylpropylenamineoxime, they were infused into the infarct-related artery without any complication. Scintigraphic images 1 (eight patients) and 24 hours (four patients) after ICI revealed an uptake of 9.2% +/- 3.6 and 6.8% +/- 2.4 of the total infused radioactivity in the infarcted area of the heart, respectively; the remaining activity was distributed mainly to liver and spleen. We conclude that through ICI of CD133(+) and CD133(-)CD34(+) BM-progenitors a significant number of them are preferentially attracted to and retained in the chronic ischemic myocardium.

AC133 Antigen↗
PubMed2005

Immunoglobulin light chain repertoire in chronic lymphocytic leukemia.

Immunoglobulin kappa (IGK) and immunoglobulin lambda (IGL) light chain repertoire was analyzed in 276 chronic lymphocytic leukemia (CLL) cases and compared with the relevant repertoires from normal, autoreactive, and neoplastic cells. Twenty-one functional IGKV genes were used in IGKV-J rearrangements of 179 kappa-CLL cases; the most frequent genes were IGKV3-20(A27), IGKV1-39/1D-39(O2/O12), IGKV1-5(L12), IGKV4-1(B3), and IGKV2-30(A17); 90 (50.3%) of 179 IGK sequences were mutated (similarity < 98%). Twenty functional IGLV genes were used in IGLV-J rearrangements of 97 lambda-CLL cases; the most frequent genes were IGLV3-21(VL2-14), IGLV2-8(VL1-2), and IGLV2-14(VL1-4); 44 of 97 IGL sequences (45.4%) were mutated. Subsets with "CLL-biased" homologous complementarity-determining region 3 (CDR3) were identified: (1) IGKV2-30-IGKJ2, 7 sequences with homologous kappa CDR3 (KCDR3), 5 of 7 associated with homologous IGHV4-34 heavy chains; (2) IGKV1-39/1D-39-IGKJ1/4, 4 unmutated sequences with homologous KCDR3, 2 of 4 associated with homologous IGHV4-39 heavy chains; (3) IGKV1-5-IGKJ1/3, 4 sequences with homologous KCDR3, 2 of 4 associated with unmutated nonhomologous IGHV4-39 heavy chains; (4) IGLV1-44-IGLJ2/3, 2 sequences with homologous lambda CDR3 (LCDR3), associated with homologous IGHV4-b heavy chains; and (5) IGLV3-21-IGLJ2/3, 9 sequences with homologous LCDR3, 3 of 9 associated with homologous IGHV3-21 heavy chains. The existence of subsets that comprise given IGKV-J/IGLV-J domains associated with IGHV-D-J domains that display homologous CDR3 provides further evidence for the role of antigen in CLL pathogenesis.

Adult↗
PubMed2005

Transferrin receptor-1 and 2 expression in chronic lymphocytic leukemia.

Transferrin receptor (TfR)-1 and 2 mRNA and CD71 (TfR1) expression was analyzed in 118 CLL patients. Ninety-five out of 109 analyzed cases expressed CD71, mostly at a high level; 60% of CD71 (+) cases were IGH-mutated. All samples were TfR1 mRNA (+); TfR2-alpha/beta mRNA was detected in, respectively, 52/102 and 100/109 cases. Competitive RT-PCR showed widely divergent levels of TfR1 mRNA in cases with high CD71 expression, alluding to post-transcriptional control of TfR1 expression in CLL. The almost uniformly high CD71 expression in CLL is in keeping with the activated status of neoplastic cells, regardless of IGH mutational load.

ADP-ribosyl Cyclase 1↗
PubMed2004

Red cell macrocytosis in hypoxemic patients with chronic obstructive pulmonary disease.

Macrocytosis is a common finding in patients with chronic obstructive pulmonary disease (COPD). The cause for the elevation of mean corpuscular volume (MCV) in these patients remains elusive. In an attempt to determine the extent of macrocytosis in COPD patients and search for possible causative factors, we evaluated the hematologic parameters, F-cell percentage, blood gases and serum erythropoietin (Epo) Levels in 32 COPD clinically stable patients and 34 sex- and age-matched non-smoker healthy volunteers. An increased MCV was observed in almost half of the hypoxemic COPD cases (14/32 or 43.75%), while erythrocytosis developed to a lesser degree (37.5%). The erythropoietic response did not correlate with the severity of hypoxia. Moreover, no significant correlation was found between macrocytosis and hypoxemia or erythrocytosis and red cell size. In some cases the two phenomena occurred independently. The F-cell percentage was significantly elevated in the COPD group (P < 0.01) and was associated with MCV values (n = 32, r5 = 0.41, P < 0.05). This finding supports the hypothesis we put forward to explain the macrocytosis often observed in COPD, i.e., that the acute erythropoietic stress occurring repeatedly in these patients as a result of the frequent exacerbations may lead to waves of release of relatively immature, large red cells from the marrow, including an increased number of F-cells, reflecting the recruitment of normally dormant BFU-E (bursts forming units of erythrocyte precursors), which maintain the program for gamma-chain synthesis. The fact that erythrocytosis and macrocytosis, both being triggered by hypoxemia, do not occur consistently in all COPD patients indicates that many other factors may also intervene.

Adult↗
PubMed2003

Decreased expression of membrane alpha4beta1, alpha5beta1 integrins and transferrin receptor on erythroblasts in splenectomized patients with beta-thalassemia intermedia. Parallel assessment of serum soluble transferrin receptors levels.

Dysfunction of cell membrane is a recognized consequence of the pathogenetic process underlying the beta-thalassemia syndromes and it is reasonable to hypothesize that surface structures crucial for the development of erythroid lineage may also be affected. The study included six adult splenectomized patients with beta-thalassemia intermedia. Expression of alpha4beta1 integrin (CD49d/CD29), alpha5beta1 integrin (CD49e/CD29) and transferrin receptor (CD71) on peripheral blood and bone marrow erythroblasts and on erythroid precursors grown in vitro was studied by flow cytometry and immunocytochemistry. Serum soluble transferrin receptor levels (sCD71) were also measured with enzyme-linked immunosorbent assay. In beta-thalassemic patients, significant reduction of CD49d, CD29 and CD71 expression was found in peripheral blood nucleated red cells, compared to patients presenting with erythroblasts in the circulation because of other diseases. Marrow erythroblasts were also deficient for the same molecules against the erythroblasts in iron deficiency anemia. All molecules tested were greatly diminished on erythroid precursors developed in vitro from the patients' cells. Serum sCD71 levels were much higher in thalassemic patients in comparison to both patients with iron deficiency anemia and healthy individuals. The loss of certain integrins and CD71 from erythroid precursors in beta-thalassemia intermedia could be attributed to a generalized membrane dysfunction, perhaps affecting the integrity of their transmembrane domains. The elevation of serum sCD71 levels may be the result of the increased red cell lineage turnover or, alternatively, may indicate increased shedding from the cells to prevent iron overload. In any case, further molecular study of the membrane components is warranted to provide a better understanding of the pathogenetic process in beta-thalassemia syndromes.

Adult↗
PubMed2003

Expression of recombination activating genes-1 and-2 immunoglobulin heavy chain gene rearrangements in acute myeloid leukemia: evaluation of biological and clinical significance in a series of 76 uniformly treated patients and review of the literature.

BACKGROUND AND OBJECTIVES: Early lymphoid differentiation is characterized by antigen receptor gene rearrangements; the rearrangement process is governed by two lymphoid-specific genes, RAG (recombinase activating gene)-1 and -2. The available data on the incidence and prognostic significance of clonal immunoglobulin heavy chain (IgH) gene rearrangements in acute myeloid leukemia (AML) are rather contradictory. The aim of this study was to evaluate the incidence and prognostic significance of RAG-1 and -2 mRNA transcripts and clonal IgH gene rearrangements in a cohort of uniformly treated AML patients; the available literature is also reviewed. DESIGN AND METHODS: The study was performed on 76 AML patients, newly diagnosed between August 1996 and November 1999. RAG-1/-2 gene expression was analyzed by a reverse transcriptase polymerase chain reaction technique and IgH gene rearrangements were detected with variable region (VH) family-specific and consensus framework region (FWR)-2 and/or-3 primers. Statistical associations were explored between IgH monoclonality/ RAG mRNA expression and: (i) age, gender, FAB subtype, immunophenotype, cytogenetic risk groups; (ii) response variables (response/relapse incidence, survival). RESULTS: In total, 38/75 samples (50.6%) were RAG-1 and/or -2 positive; 30/76 samples (39.5%) carried clonal IgH genes, whereas 13/30 IgH-positive samples (43.3%) were RAG-1/2-negative. Significant associations were detected only for RAG-2 positivity and unfavorable karyotype and IgH monoclonality and FAB subtypes M4/ M5; no association was identified with response outcome and survival. INTERPRETATION AND CONCLUSIONS: Lymphoid-specific molecular markers are detected in a significant proportion of AML patients, regardless of differentiation status (assessed morphologically/ immunophenotypically); however, in our experience, they do not seem to constitute an adverse prognostic factor.

Acute Disease↗
PubMed2002

Evaluation of the clinical relevance of the expression and function of P-glycoprotein, multidrug resistance protein and lung resistance protein in patients with primary acute myelogenous leukemia.

The multidrug resistance (MDR) transporter-proteins P-glycoprotein (Pgp), multidrug resistance protein (MRP) and lung resistance protein (LRP) have been associated with treatment failure. The aim of this study was to investigate prospectively the clinical significance of expression and function of the MDR proteins, considering other prognostic factors, such as age, immunophenotype, and cytogenetics. Mononuclear cells of peripheral blood or bone marrow from 61 patients with de novo acute myelogenous leukemia (AML) were analyzed. The monoclonal antibodies JSB1, MRPm6 and LRP56 were used for expression studies. Accumulation and retention studies were performed using the substrates Daunorubicin, Calcein-AM, Rhodamine-123 and DiOC(2) in the presence or absence of the modifiers Verapamil, Genistein, Probenecid, BIBW22S and PSC833. Induction treatment consisted of a 3+7 combination of Ida/Ara-C for patients < or = 60 years of age and a 3+5 Ida/VP-16 combination per OS for patients >60. MDR function was expressed as the ratio of mean fluorescence intensity substrate in the presence of modifier over the substrate alone (resistance index, RI). Patients with advanced age, low CD15 expression and high RI for accumulation of DiOC(2) in the presence of BIBW22S had significantly lower complete remission (CR) rates. No factor was prognostic for event-free survival analysis, which was limited to remitters only. Overall survival was shorter in patients with advanced age, poor prognosis cytogenetics, high CD7 expression, and high RI for Daunorubicin efflux modulated by Verapamil. These results suggest that MDR transporter-proteins have a limited role in the treatment failure of patients treated with Idarubicin-based regimens.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Lymphocyte subpopulations and interleukin levels in high-risk melanoma patients treated with high-dose interferon A-2B.

Immunologic effects of high-dose interferon are still unclear. We have evaluated changes in blood lymphocyte subpopulations, immunoglobulins, and multiple interleukin in patients with high-risk cutaneous melanoma on adjuvant treatment with high-dose interferon and compared pretreatment values with normal controls. Samples were obtained before treatment, 1 month after induction treatment and at 3, 6, and 12 months of maintenance treatment from 24 patients with high-risk melanoma. Lymphocyte subpopulations were measured by flow cytometry and interleukin and immunoglobulin levels by radioimmunoassay. A statistically significant reduction in B-lymphocytes (p < 0.001), natural killer (NK) cells (p = 0.0004), and monocytes (p = 0.04), and an elevation in CD4/CD8 ratio (p < 0.0001) was observed after 1 month of intravenous interferon. No changes were seen in CD3, CD4, and CD8 lymphocytes. No changes in interleukin (IL)-2, -4, or -5 were observed during 1 year of treatment. IL-2 pretreatment levels were significantly lower than healthy blood donors (p = 0.001), and IL-5 pretreatment levels were significantly higher (p = 0.0056). IL-10 levels significantly dropped after 6 months of treatment (p = 0.01). Immunoglobulins (IgG, IgA, IgM) remained within normal ranges. Three patients had elevated pretreatment levels of IgE. There is a time- and dose-dependent impact of interferon on numbers of circulating B lymphocytes, NK cells, monocytes, and CD4/CD8 ratio. Defects in cellular and humoral immunity are suggested by the low IL-2 and high IL-5 levels, measured in patients with melanoma as compared with healthy controls.

Adult↗
PubMedDate not supplied

Analysis of expressed and non-expressed IGK locus rearrangements in chronic lymphocytic leukemia.

Immunoglobulin kappa (IGK) locus rearrangements were analyzed in parallel on cDNA/genomic DNA in 188 kappa- and 103 lambda-chronic lymphocytic leukemia (CLL) cases. IGKV-KDE and IGKJ-C-intron-KDE rearrangements were also analyzed on genomic DNA. In kappa-CLL, only 3 of 188 cases carried double in-frame IGKV-J transcripts: in such cases, the possibility that leukemic cells expressed more than one kappa chain cannot be excluded. Twenty-eight kappa-CLL cases also carried nonexpressed (nontranscribed and/or out-of-frame) IGKV-J rearrangements. Taking IGKV-J, IGKV-KDE, and IGKJ-C-intron-KDE rearrangements together, 38% of kappa-CLL cases carried biallelic IGK locus rearrangements. In lambda-CLL, 69 IGKV-J rearrangements were detected in 64 of 103 cases (62%); 24 rearrangements (38.2%) were in-frame. Four cases carried in-frame IGKV-J transcripts but retained monotypic light-chain expression, suggesting posttranscriptional regulation of allelic exclusion. In all, taking IGKV-J, IGKV-KDE, and IGKJ-C-intron-KDE rearrangements together, 97% of lambda-CLL cases had at least 1 rearranged IGK allele, in keeping with normal cells. IG repertoire comparisons in kappa- versus lambda-CLL revealed that CLL precursor cells tried many rearrangements on the same IGK allele before they became lambda producers. Thirteen of 28 and 26 of 69 non-expressed sequences in, respectively, kappa- or lambda-CLL had < 100% homology to germline. This finding might be considered as evidence for secondary rearrangements occurring after the onset of somatic hypermutation, at least in some cases. The inactivation of potentially functional IGKV-J joints by secondary rearrangements indicates active receptor editing in CLL and provides further evidence for the role of antigen in CLL immunopathogenesis.

Adult↗