Gianluigi Castoldi

CD34+ and Endothelial Progenitor Cells in Patients With Various Degrees of Congestive Heart Failure

Background—Peripheral blood CD34+ cells and circulating endothelial progenitor cells (EPCs) increase in myocardial infarction and vascular injuries as a reflection of endothelial damage. Despite the occurrence of endothelial dysfunction in heart failure (HF), no data are available on EPC mobilization in this setting. We investigated the pattern of CD34+ cells and EPC mobilization during HF and their correlation with the severity and origin of the disease. Methods and Results—Peripheral blood CD34+ cells (n=91) and EPCs (n=41), assessed both as CD34+ cells coexpressing AC133 and vascular endothelial growth factor (VEGF) receptor-2 and as endothelial colony-forming units, were studied in HF patients (mean age 67±11 years) and 45 gender- and age-matched controls. Tumor necrosis factor-&agr; (TNF-&agr;) and its receptors (sTNFR-1 and sTNFR-2), VEGF, stromal derived factor-1 (SDF-1), granulocyte-colony stimulating factor (G-CSF), and B-type natriuretic peptide were also measured. CD34+ cells, EPCs, TNF-&agr; and receptors, VEGF, SDF-1, and B-type natriuretic peptide were increased in HF. CD34+ cells and EPCs were inversely related to functional class and to TNF-&agr;, being decreased in New York Heart Association class IV compared with class I and II and controls. No role was found for the origin of the disease. Conclusions—CD34+ cells and EPC mobilization occurs in HF and shows a biphasic response, with elevation and depression in the early and advanced phases, respectively. This could be related to the myelosuppressive role of TNF-&agr;.

A His-155 to Tyr Polymorphism Confers Gain-of-Function to the Human P2X7 Receptor of Human Leukemic Lymphocytes

The P2X7R is an ATP-gated cation channel expressed in hemopoietic cells that participates in both cell proliferation and apoptosis. Expression and function of the P2X7R have been associated with the clinical course of patients affected by chronic lymphocytic leukemia (CLL). Functional variants causing loss-of-function of the P2X7R have been identified, namely, polymorphisms 1513A>C (E496A), 1729T>A (I568N), and 946G>A (R307Q). Here we investigated other nonsynonymous polymorphisms located either in the extracellular portion of the receptor, such as the 489C>T (H155Y) variant, or in the long cytoplasmic tail of the receptor, such as the 1068G>A (A348T), 1096C>G (T357S), and 1405A>G (Q460R) variants. P2X7R function was monitored by measuring ATP-induced Ca2+ influx in PBL of patients affected by CLL and in recombinant human embryonic kidney (HEK) 293 cells stably transfected with each single P2X7 allelic variant. Ca2+ influx was markedly reduced in association with the 1513C allele, whereas variants located in the same intracellular domain, such as the 1068A, 1096G, or 1405G variants, were associated with a minor functional decrease. Significant Ca2+ flux increase was observed in lymphocytes from CLL patients bearing the 489C/T and 489T/T genotypes in association with the 1513A/A genotype. Functional analysis in recombinant HEK293 cells expressing P2X7R confirmed an increased ATP-dependent activation of the P2X7 489T mutant with respect to the wild type receptor, as assessed by both by [Ca2+]i influx and ethidium uptake experiments. These data identify the 489C>T as a gain-of-function polymorphism of the P2X7R.

A 3-cM commonly deleted region in 6q21 in leukemias and lymphomas delineated by fluorescence in situ hybridization†

Deletions of the long arm of chromosome 6 (6q) are frequent chromosome aberrations in non‐Hodgkin lymphomas (NHLs) and acute lymphoblastic leukemias (ALLs). It is presumed that one or more tumor suppressor genes are localized on 6q. By means of fluorescence in situ hybridization (FISH), we attempted to detect and delineate deletions of 6q in leukemias and lymphomas. We performed FISH on 148 cases of lymphoma and acute leukemia using a panel of 36 YAC probes distributed from 6q12 to 6q27 and a centromeric probe of chromosome 6 as internal control. Deletions of 6q that included a 7‐cM commonly deleted region in 6q21 were detected in 59 patients who had B‐ and T‐cell low‐grade and high‐grade NHL and ALL. FISH with two YAC probes flanking this region was performed on an additional 97 cases of NHL and leukemia. Deletions in 6q21 were detected in an additional 21 cases. In five cases of high‐grade B‐ and T‐cell NHL and ALL, the deletion breakpoints were located within the commonly deleted region. To define the deletion breakpoints exactly and to narrow this region further, FISH was performed with six additional YAC probes that have been physically localized within this region. A 3‐cM (4–5 Mb) commonly deleted region in 6q21 was delineated. Our study suggests that this commonly deleted region harbors a putative tumor suppressor gene involved in the pathogenesis of both low‐grade and high‐grade NHL and ALL. Genes Chromosomes Cancer 27:52–58, 2000.

Exposure to myelotoxic agents and myelodysplasia: case–control study and correlation with clinicobiological findings

To better define the role of exposure to myelotoxic agents in the genesis of myelodysplastic syndrome (MDS), we carried out (a) a case–control study for the determination of the relative risk (RR) of developing MDS, including 178 consecutive patients and 178 sex‐ and age‐matched controls; (b) a study of clinicobiological features in MDS arising after occupational exposure to myelotoxic agents and in MDS in ‘non‐exposed’ patients. The definition of the ‘exposure’ status was based on a predetermined questionnaire, with calculation of an ‘exposure’ index (hours/day × days/year × years). Cumulative exposure to pesticides or to organic solvents, for >2400 h, was recorded in 48 and 25 MDS patients, respectively, compared to 27 and four controls (P < 0.00001; RR 3.74; 95% confidence interval 2.02–5.37). Older age and an excess of refractory anaemia with ringed sideroblasts and refractory anaemia with excess of blasts was noted among ‘exposed’ MDS‐patients (group 1), compared to non‐exposed MDS‐patients (group 2). 68.3% patients in group 1 had clonal chromosome changes, compared with 43.2% patients in group 2. Complex karyotypes, −7/7q−, −5/5q−, +8, 7p and 17p aberrations were seen more frequently in group 1, whereas a normal karyotype, isolated 5q− or 20q− occurred more frequently in group 2. The association of exposure to myelotoxic agents with older age at presentation and with unfavourable chromosome changes accounted for the shorter survival observed in ‘exposed’ patients. These data show that occupational exposure to pesticides and organic solvents in our region resulted in an increased RR of developing MDS and that a distinct cytogenetic profile was associated with MDS in ‘exposed’ patients. These findings provide strong indirect evidence that these agents may play a role in the pathogenesis of MDS, preferentially targeting some of the chromosome regions which are frequently involved in therapy‐related myeloid neoplasias.

Dendritic cells and vascular endothelial growth factor in colorectal cancer: correlations with clinicobiological findings.

Objective: Dendritic cells (DC) are central to the development of immune system responses. In a cohort of 54 patients affected by colorectal cancer, we prospectively investigated the number of peripheral blood (PB) DC type 1 (DC1) and type 2 (DC2) and correlated their counts and functionality to the stage of the disease and to vascular endothelial growth factor (VEGF) levels. Results: At diagnosis, compared with healthy controls, patients presented reduced PBDC1 and PBDC2 numbers (p < 0.001). Moreover, in cancer patients, PBDC showed low levels of DC-associated antigens (HLA DR, p = 0.004; CD11c, p < 0.001; CD83, p = 0.01; CD86, p = 0.007 and Mannose receptor, p = 0.029), an upregulation of CXCR4 (p = 0.017) and a reduced T cell stimulation capability (p < 0.001). DC1 and DC2 loss was higher in stage D versus stage ABC patients (p = 0.003 and p = 0.002, respectively); surgery and chemotherapy appeared to attenuate a DC defect, although the restoration of normal PBDC levels is completed only at 6 and 12 months after diagnosis, respectively. In this series of patients, PBDC1 and PBDC2 numbers inversely correlated with VEGF serum levels (p < 0.001), suggesting a possible effect of this cytokine on DC compartment. In culture, the exposure of monocyte-derived DC to VEGF produced a dramatic alteration of DC differentiation by (1) induction of apoptosis, (2) alteration of DC immunophenotypic profile and (3) increased CXCR4 expression. Exposure to anti-VEGF blocking antibodies reversed VEGF inhibitory effects in all cases. Conclusions: These findings suggest that in colorectal cancer patients there is a numerical and functional impairment of PBDC compartment possibly related to the stage of the disease and to VEGF levels.

Morphologic, immunologic and cytogenetic studies in acute myeloid leukemia following occupational exposure to pesticides and organic solvents.

In order to analyze the correlation between environmental exposure and the clinicopathological picture in acute myeloid leukemia (AML), cytogenetic, cyto-immunologic and clinical studies were performed in 70 newly diagnosed AML patients, 30 of which were anamnestically exposed to pesticides (21 cases) or to organic solvents (9 cases). Clonal chromosome aberrations, with involvement of chromosome 5 and/or 7 were more frequently encountered among exposed patients. While the classical t(15;17), t(8;21) and t(9;11) were detected more frequently among non-exposed patients, other recurring chromosome changes in the exposed group were: rearrangements leading to total or partial monosomy 17p (5 cases), structural aberrations involving the band 16q22 (4 cases), trisomy 11q (2 cases), breaks involving bands 6p23, 7p14, 11q13 (2 cases each). Cytologically, trilineage myelodysplasia was observed in 21 exposed patients, whereas morphologic aberrations of the non-blast cell population were confined to a minority of cells in most patients non-exposed. Immunologic studies revealed positivity for the CD34 stem cell marker in 80% exposed patients vs 22% in the non-exposed group. Conventional chemotherapy achieved complete remission in 3/21 patients exposed and in 16/32 patients non-exposed. Median survival was 2 months in the former group and 9 months in the latter group. These findings show that AML following occupational exposure to pesticides and organic solvents may represent a distinct cytogenetic and clinicopathological entity.

Atypical chronic lymphocytic leukaemia witht(ll;14)(ql3;q32): karyotype evolution and prolymphocytic transformation

Summary. In order to define better the cytological and clinical features of atypical B‐cell chronic lymphocytic leukaemia (B‐CLL) with t(ll;14)(ql3;q32), sequential morphologic immunological and cytogenetic studies were performed in seven patients belonging to a series of 72 consecutive cases presenting with a diagnosis of CLL or atypical CLL according to the FAB criteria.

Distinct cytogenetic and clinicopathologic features in acute myeloid leukemia after occupational exposure to pesticides and organic solvents

Background. To study the correlation of environmental exposure to potentially mutagenic agents and the clinicopathologic picture in acute myeloid leukemia (AML), clinical features, morphologic characteristics, immuno‐phenotype, and cytogenetics were studied in 59 patients with newly diagnosed AML.

Comparative analysis of different permeabilization methods for the flow cytometry measurement of cytoplasmic myeloperoxidase and lysozyme in normal and leukemic cells

Using a direct one-color (fluorescein isothiocyanate; FITC) staining method with a Facscan flow cytometer, we evaluated the intracellular expression of two granular constituents of myeloid cells [myeloperoxidase (MPO) and lysozyme] on leukemic cells from 21 patients with acute myeloid leukemia (AML), and 6 patients with acute lymphoblastic leukemia (ALL). Three different permeabilization techniques were used [FACS Lysing Solution (FLy), B.Dis; Ortho-PermeaFix (OPF); Fix and Perm (F&P), Caltag] prior to monoclonal antibody (McAb) staining, in order to verify the specificity and the sensitivity of the three labelling methods towards the two model antigens. Peripheral blood cells from 15 healthy subjects and Ortho Absolute Control served as controls. Data were expressed as percentage of positivity, net fluorescence intensity, ratio between mean fluorescence intensity (MFI) of positive cells and that of isotypic controls (P/N ratio; evaluated in both geometric and arithmetic scale), and, in 12 representatives cases (7 AML, 5 normal samples), in the form of both molecules of equivalent soluble fluorochromes (MESF) and antibody binding capacities (ABC). As far as the antigenic expression of MPO and lysozyme in normal samples is concerned, F&P resulted, in our hands, in the most specific and sensitive staining, followed by FLy solution and OPF, which showed positivity for MPO, and, to lesser extent, for lysozyme in a considerable manner of lymphocytes (means 64% and 54%, respectively, for OPF and FLy; range of ABC/cell: 0.9-5.2 x 10(3)) obtained from healthy subjects. With the reference F&P permeabilizing solution, 90% and 80% of FAB M1-M5 cases were found to be positive for MPO and lysozyme, respectively. However, M1, M2, and M3 AML FAB (French-American-British) subvarieties were characterized by a brighter expression for MPO (mean ABC/cell: 89 x 10(3)) than that of lysozyme (mean ABC/cell: 12.5 x 10(3D)), whereas blast cells from patients with M5a FAB subtypes showed higher levels of lysozyme (mean ABC/cell: 65 x 10(3)) than that of MPO (mean ABC/cell: 0.1 x 10(3)). One of five cases of FAB MO AML showed a dull positivity for MPO-7 McAb. Patients with ALL were MPO and lysozyme negative using both F&P and FLy reagents, although a certain degree of positivity was documented in some cases with OPF. Taking these data together, it can be stated that the use of anti-MPO McAbs may be of great value for the diagnosis and monitoring of acute leukemia and, along with lysozyme McAb, can provide useful information in the distinction of myeloid from monocytic leukemias and in the lineage assignment of apparently biphenotypic forms. However, the methodology used for the detection of these myeloid-associated antigens is critical for a correct interpretation of cytofluorimetric data and should be taken into account when evaluating data coming from multicenter trials dealing with leukemias. A standardization of cytofluorimetric analysis of intracellular antigens is needed in order to improve the reproducibility and comparability of results in multicenter studies.

Phenotypic and functional characteristics of monocyte-derived dendritic cells from patients with myelodysplastic syndromes

We have compared the phenotypic and functional characteristics of dendritic cells (DC) generated in vitro from the peripheral blood mononuclear fraction of myelodysplastic syndrome (MDS) patients (four refractory anaemia, four refractory anaemia with excess of blasts) with DCs generated in a similar way from eight healthy donors. After 10 d of culture in the presence of GM‐CSF and IL‐4, reduced numbers and percentages of DCs were obtained in MDS subjects. MDS DCs exhibited significantly lower expression of CD1a, CD54, CD80 and MHC class II molecules. Their ability to stimulate T lymphocytes in an allogeneic mixed leucocyte reaction was reduced in comparison to normal subjects. Furthermore, MDS DCs also showed a reduced receptor‐mediated endocytosis as demonstrated by FITC‐dextran uptake. Simultaneous fluorescence in situ hybridization (FISH) and immunophenotypic analysis demonstrated that MDS DCs have the same cytogenetic abnormality of the malignant clone. Taken together these findings indicate that, in MDS, DCs are part of the malignant clone and exhibit a deficient antigen uptake and presentation.