Biomedical subjects

G Melioli

Publications and source records attributed to G Melioli.

At least 19 recordsLinked to original sources

PubMed2007

New approach for rapid detection of known hemoglobin variants using LC-MS/MS combined with a peptide database.

The identification of hemoglobin (Hb) variants is usually performed by means of different analytical steps and methodologies. Phenotypic methods, such as gel electrophoresis and high performance liquid chromatography, are used to detect the different electrophoretic or chromatographic behaviors of hemoglobin variants in comparison to HbA0 used as a control. These data often need to be combined with mass spectrometry analyses of intact globins and their tryptic peptide mixtures. As an alternative to a 'step-by-step' procedure, we have developed a 'single step' approach for the identification of Hb variants present in biological samples. This is based on the microHPLC-ESI-MS/MS analysis of the peptide mixture generated by a tryptic digestion of diluted Hb samples and an in-house new database containing solely the variant tryptic peptide of known human Hb variants. The experimental results (full MS and MS/MS spectra) are correlated with theoretical mass spectra generated from our in-house-built variant peptide database (Hbp) using the SEQUEST algorithm. Simple preparation of samples and an automated identification of the variant peptide are the main characteristics of this approach, making it an attractive method for the detection of Hb variants at the routine clinical level. We have analyzed 16 different samples, each containing a different known variant of hemoglobin.

Amino Acid Sequence↗

PubMed2003

Indirect evidence of hormone abuse. Proof of doping?

Besides anabolic steroids, the most common performance-enhancing hormones are erythropoietin (EPO), insulin, GH, and gonadotropins, mostly indistinguishable from endogenous hormones and with very short half-life. This makes virtually impossible to demonstrate their use by measuring their concentration in the blood or urine. A possible approach to the problem may lie in in-direct demonstration through detection of the biological effects of these substances. The finding of an increased hematocrit level is suspicious but not clearly demonstrative of EPO abuse. Very high levels of circulating EPO could be associated with a strong suspicion of doping, when associated to other abnormal parameters, such as Ht, sTFRr, EPO, RDW. The presence of antibodies against the polysaccharide fraction of lateral chains of EPO has been observed only in patients treated with rhEPO. Owing to the pulsatile pattern of GH, particularly during physical exercise, pathologically high values may be found in normal subjects. Therefore, as in the case of EPO, evidence of GH abuse can be gathered only indirectly by detecting the biological effects of its administration. In training subjects GH treatment increased GH, IGF-I, IGFBP-3 and ALS, and decreased IGBP-2. After cessation of treatment IGF-I, IGFBP-3 and ALS approached basal values between 49 and 96 h. Also the bone parameters PICP ICIP, PIUP and osteocalcin increased significantly. Four days after cessation of treatment, levels of PIIIP and ICTP were still abnormally elevated. In conclusion, increases in IGF-I, IGFBP-3, ALS, PIIIP and ICTP are all indicative of recent GH abuse or of acromegaly.

Antibodies↗

PubMed2003

Surface receptors and functional interactions of human natural killer cells: from bench to the clinic.

The past 10years have witnessed dramatic progress in our understanding of how natural killer (NK) cells function and their role in innate immunity. Thanks to an array of inhibitory receptors specific for different HLA class I molecules, human NK cells can sense the decrease or loss of even single alleles at the cell surface. This represents a typical condition of a potential danger, i.e. the presence of tumor or virally infected cells. NK cell triggering and lysis of these cells is mediated by several activating receptors and coreceptors that have recently been identified and cloned. While normal cells are usually resistant to NK-mediated attack, a remarkable exception is represented by dendritic cells (DCs). In their immature form they are susceptible to NK-mediated lysis because of the expression of low levels of surface HLA class I molecules. The process of DC maturation (mDCs) is characterized by the surface expression of high levels of HLA class I molecules. Accordingly, mDCs become resistant to NK cells. A recent major breakthrough highlighted the role played by donor NK cells in allogenic bone marrow transplantation to cure acute myeloid leukemias. 'Alloreactive' NK cells derived from donor hematopoietic precursors not only prevented leukemic relapses, but also prevented graft rejection and graft-versus-host disease.

Dendritic Cells↗

PubMed2003

Low concentrations of cytokines produced by allergen-stimulated peripheral blood mononuclear cells have potent effects on nasal polyp-derived fibroblasts.

Accumulating data show that fibroblasts are important regulators in the development and maintenance of allergic airway inflammation. However, most studies so far have used individual recombinant cytokines in high concentrations, unlikely to be found in vivo. We aimed to investigate how cytokines produced by peripheral blood mononuclear cells (PBMC) affect fibroblast functions. Primary airway fibroblasts where incubated with allergen-stimulated or non-stimulated PBMC supernatants from allergic patients. The levels of cytokines in PBMC supernatants were measured and the expression of CD54, CD40 and CD106 as well as the production of eotaxin, interleukin (IL)-6 and IL-8 were assessed in fibroblasts. Although the levels of single cytokines measured in PBMC supernatants were low, a significant up-regulation of the surface molecules as well as of IL-6 and IL-8 production was found in fibroblasts cultured with allergen-stimulated PBMC supernatants as compared to non-stimulated, while the increase in eotaxin production was not significant. The evaluation of correlations between cytokines produced by PBMC and effects seen on fibroblasts did not indicate a crucial role for any single cytokine. Furthermore, the addition of comparably low concentrations of recombinant interferon (rIFN)-gamma or recombinant tumour necrosis factor (rTNF)-alpha did not induce the same effects as PBMC supernatants, the only exception being TNF-alpha as a direct inducer of CD54 expression. Our results show that synergistic mechanisms has a more important role than single mediators, highlighting important differences between in vitro experiments, where effects of individual mediators are studied, versus the actual situation in vivo.

Cells, Cultured↗

PubMed2002

A defective expression of ICAM-1 (CD54) on secretory endometrial cells is associated with endometriosis.

A defect in the cytolytic activity against autologous endometrial cells refluxed in the peritoneal cavity has been hypothesized as being involved in the etiology of endometriosis, although its causes have not been definitively identified. Cell adhesion molecules are necessary not only for cell-to-cell contact but also for the binding of immune effectors to their targets. In this study, the expression of CD54, CD58 and CD106, three adhesion molecules with a crucial role in cytotoxic mechanisms, was quantitatively studied on fresh endometrial cells by immunofluorescence and flow cytometry. Samples were collected from endometriosis patients (n=10) and controls (n=12), either during the follicular or luteal phase of the cycle. While no significant differences were observed for CD58 and CD106, a significantly reduced expression of CD54 in the secretory endometrial cells of women with endometriosis was observed (-75% with respect to apparently healthy controls). These findings could account for an apparently cyclic defect in the expression of CD54 that could result in poor binding of immune effectors to secretory endometrial cells in vivo. The defective recognition and removal of refluxed endometrial cells could, at least in part, be involved in the pathogenesis of endometriosis.

Adult↗

PubMed2001

HLA class I molecule expression is up-regulated during maturation of dendritic cells, protecting them from natural killer cell-mediated lysis.

It has been widely demonstrated that natural killer (NK) cells are able to discriminate between normal and abnormal cells on the basis of the interaction of their NKRs with the MHC molecules expressed on the target cells. Recent studies showed that also normal dendritic cells are susceptible to NK cell-mediated lysis. In this work, the potential relationships between the expression of different surface molecules on both immature and mature DC and susceptibility to lysis have been investigated. The reduced density of HLA class I on the surface of immature DC resulted in the only permissive signal to NK cell mediated killing. On the contrary, the remarkable increase in HLA class I molecules detected during DC maturation was strictly related to the resistance to NK cell. Contemporary, no clear evidences of a role for other surface molecules modulated during DC maturation (CD80, CD83, CD86 and CD40), were obtained.

Antibodies, Monoclonal↗

PubMed2001

Analysis of HLA-class-I specific natural killer cell receptors expressed on T lymphocytes infiltrating non-small-cell lung cancer.

HLA-class I-specific natural killer cell receptors (HNKR) have been described to significantly interfere with both specific and non-specific functional activities of T lymphocytes. Despite the clear evidences obtained in T cells derived from peripheral blood, little is known about the activity of HNKR expressed in tumor infiltrating lymphocytes. For this reason, we have studied T lymphocytes derived from advanced non small cell lung cancers (NSCLC). The population of T cells expressing the HNKR(+) phenotype was rare both in NSCLC-associated lymphocytes and in the peripheral blood. The two populations were clearly oligoclonal, as shown by the analysis of T cell receptor repertoire. Interestingly, while HNKR(+) T cells derived from the peripheral blood belonged to the CD45R0 phenotype, the large majority of HNKR(+) T cells in TIL were CD45RA. Functionally, all HNKR(+) T cells displayed a cytolytic activity against allogeneic NSCLC. Autologous NSCLC, tested in a single patient, was lysed efficiently by HNKR(+) T cells, thus suggesting that at least in this model, the presence of HNKR did not significantly interfere with the functional capacity of effector cells.

Aged↗

PubMed2001

Intensified chemotherapy supported by DMSO-free peripheral blood progenitor cells in breast cancer patients.

BACKGROUND: The majority of high-dose chemotherapy (HDC)-related complications results from bone marrow aplasia, but the graft infusion per se may cause adverse reactions due to the injection of both dimethyl sulfoxide (DMSO) and cell lysis products. We evaluated the feasibility of a two-step chemotherapy regimen with peripheral blood progenitor cell (PBPC) support in association with a novel procedure to remove DMSO and products of cell lysis from the cryopreserved cells. PATIENTS AND METHODS: Stage III and IV breast cancer patients received induction chemotherapy with three cycles of CEF (cyclophosphamide 600 mg/m2, epirubicin 100 mg/m2, 5-fluorouracil 600 mg/m2) followed by three cycles of HDC consisting of escalating doses of cyclophosphamide (dose range 1200 3000 mg/m2) and carboplatin (dose range 600-1000 mg/m2), supported by DMSO-free PBPC reinfusion. DMSO was removed by a washing/enzymatic digestion procedure. RESULTS: Twenty patients received induction chemotherapy and eighteen completed the entire chemotherapy program; a total of fifty-four cycles of HDC were administered. Dose limiting toxicity of HDC was long-lasting grade 4 neutropenia associated with documented infection. The maximum tolerated dose (MTD) was cyclophosphamide 3000 mg/m2 and carboplatin 600 mg/m2. No side effects related to PBPC reinfusion were observed. CONCLUSIONS: The proposed two-step chemotherapy regimen, associated with a novel washing/enzymatic digestion procedure, is feasible in advanced breast cancer patients in the absence of complications related to the specific toxicity of PBPC reinfusion.

Adult↗

PubMed2000

Heterogeneity of tonsillar subepithelial B lymphocytes, the splenic marginal zone equivalents.

The VH4 genes expressed by both resting and in vivo-activated subepithelial (SE) B cells from human tonsils were studied. Resting SE B cells were subdivided according to the presence (IgDlow) or absence (IgM-only) of surface IgD. CD27 was abundant on activated SE B cells and low on resting IgM-only B cells. Resting IgDlow SE B cells could be subdivided into CD27low and CD27high cell fractions. Resting IgDlow SE B cells displayed VH4 genes with a substantial number of mutations (13/29 of the molecular clones were mutated), whereas 25/26 of the clones from resting IgM-only SE B cells were unmutated. Moreover, mutated VH4 genes were detected mainly within the CD27high cell fraction of the IgDlow SE B cells. Several identical unmutated VH4DJH sequences (11/32) were found in different molecular clones from resting IgM-only SE B cells, suggesting local cellular expansion. Both unmutated (14/25) and mutated (11/25) sequences were found in mu transcripts of activated SE B cells. Extensive mutation was observed in the gamma transcripts of activated SE B cells. Therefore, SE B cells are heterogeneous, being comprised of B cells with mutated Ig VH4 genes, that are Ag-experienced B cells, and a subset of B cells with unmutated VH4 genes that are either virgin cells or cells driven by Ags that did not induce or select for V gene mutations.

B-Lymphocyte Subsets↗

PubMed2000

Cetirizine-induced downregulation of airway fibroblast proliferation and function: a rationale for a different approach to allergy treatment?

Recently, airway fibroblasts captured the attention of both allergists and basic scientists since they are no longer considered as mere bystanders, as far as allergic airway diseases are concerned. The aim of the present study was to assess the effects of different Cetirizine (Cet) concentrations (0.01, 0.05, 0.1 mg/ml) on human airway fibroblast proliferation and on CD54 expression. By means of flow cytometry analysis, we evaluated CD54 expression by airway fibroblasts in basal conditions or after gammaIFN stimulation in the presence of Cetirizine; we also evaluated the effect of the drug on cell proliferation by a [3H]thymidine incorporation assay. All of the tested doses of Cetirizine were able to significantly reduce CD54 upregulation induced by gammaIFN; concerning the fibroblast proliferation, we observed a dose-dependent inhibition of [3H]thymidine incorporation. These results show that Cetirizine exerts a biologic effect directly on human airway fibroblasts, suggesting a new rationale in the use of this compound.

Anti-Allergic Agents↗

PubMed2000

Engagement of CD33 surface molecules prevents the generation of dendritic cells from both monocytes and CD34+ myeloid precursors.

Although CD33 represents an important marker of myeloid cell differentiation, its function remains poorly defined. In view of its homology with p75/AIRM1, a recently identified surface molecule which exerts a potent inhibition on NK cell function, we re-evaluated the effect of CD33 engagement in defined myeloid cell functions. Addition of anti-CD33 mAb to cultures of CD14+ monocytes supplemented with granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-4 and TNF-alpha, prevented the generation of dendritic cells. In these cultured cells, engagement of CD33 resulted in an increased surface binding of annexin-V, followed by cell death. Mature dendritic cells were resistant to the CD33-mediated effect. Also in CD34+ precursors, cultured in the presence of flt3-ligand, c-Kit-ligand, GM-CSF, IL-4 and TNF-alpha, addition of anti-CD33 mAb prevented the recovery of mature dendritic cells. These data suggest a regulatory role of CD33 in the myeloid cell maturation and may offer a tool to interfere with the monocyte/macrophage cell function as well as with the development of dendritic cells.

Antibodies, Monoclonal↗

PubMed2000

Detection of anti-erythropoietin antibodies in haemodialysis patients treated with recombinant human-erythropoietin.

An enzyme-immunoassay was developed to evaluate the presence of anti-erythropoietin antibodies in plasma samples obtained from renal failure patients treated with recombinant human erythropoietin (rh-EPO). The assay was specific and reproducible. Normal donors had no antibodies to EPO, while 67% of treated patients were positive to the assay. While the specificity of anti-EPO IgG antibodies was high, their affinity for the antigen was low. This finding can be explained by the very small differences in the structure of rh-EPO compared to that of natural EPO. The assay described could be useful in evaluating the long-term effects of rh-EPO treatment on the control of anaemia in renal failure patients.

Anemia↗

PubMed2000

Quantitative flow cytometric analysis of the effects of cetirizine on the expression of ICAM-1/CD54 on primary cultured nasal cells.

An in vitro flow cytometric model has been developed to evaluate the effects of antiallergic drugs such as cetirizine (CTZ) on the expression of surface molecules on primary cultured normal cells. Quantitative analysis demonstrated that HLA class I and ICAM-1/CD54 molecules are present on both epithelial and stromal cells, and that their expression is strongly enhanced by treatment with interferon-gamma (IFN-gamma). Nevertheless, the IFN-gamma-mediated upregulation of ICAM-1/CD54 was inhibited by treatment with CTZ, demonstrating a direct effect on both cell types. This finding is particularly interesting because ICAM-1/CD54 is the main rhinovirus receptor, and rhinoviruses are the principal cause of asthma exacerbation in children. Thus, according to data derived from this in vitro model, CTZ should have an important role in the reduction of infectious exacerbation of asthma in atopic patients.

Adult↗

PubMed2000

alpha-Interferon treatment induces quantitative modifications of HLA class I-associated peptides eluted from cultured cancer cell lines.

Interferons upregulate the expression of HLA class I antigens on cancer cells. Nevertheless, little is known about the panel of HLA class I antigen-associated peptides presented by recombinant alpha-interferon (r(alpha)-IFN)-treated cells. For this reason, peptides were eluted from five cancer cell lines (four melanoma and one non-small cell lung cancer) following treatment with r(alpha)-IFN. High-performance liquid chromatography (HPLC) profiles of the peptide fractions were compared with those obtained from untreated cells. No significant differences in peptide characteristics (detectable on the basis of retention times) were observed, but significant differences in terms of peptide quantities were observed. Mass spectrometry performed on HPLC peaks allowed not only the detection of three different peptides (two derived from the MAGE family of genes and one from the mart-1) both in untreated and in treated cells, but also gave an indication of the number of peptides within one HPLC peak. This data demonstrates that r(alpha)-IFN-treated cells express a similar peptide pattern as untreated cells, with significant quantitative differences. Interestingly, this finding also explains the higher susceptibility to lysis (mediated by specific cytolytic lymphocytes, which recognize cancer cells in an HLA-restricted fashion) of r(alpha)-IFN-treated cells.

Antigens, Neoplasm↗

PubMed2000

Dendritic cells efficiently cross-prime HLA class I-restricted cytolytic T lymphocytes when pulsed with both apoptotic and necrotic cells but not with soluble cell-derived lysates.

Dendritic cells (DC) have been shown to efficiently present antigen to CD8(+) cytolytic T cells (CTL) when pulsed with apoptotic cells as a source of cell-derived antigen. Such cross-priming could not be detected by the use of necrotic cells, while conflicting results have been reported for cell-derived soluble lysates. In this study, we reinvestigated this issue by using autologous Epstein-Barr virus-transformed lymphoblastoid cell lines (LCL) as a source of antigen to pulse monocyte-derived DC. Both autologous and HLA-mismatched allogeneic LCL have been used either in the form of apoptotic or of necrotic cells or of soluble cell lysates. At day 7, DC were co-cultured with the autologous CD8(+) lymphocyte fraction for an additional 9 days, in the presence of exogenous IL-2 (added after 48 h). At the end of the culture period, CD8(+) CTL efficiently lysed autologous LCL only when they had been co-cultured with DC pulsed with necrotic or apoptotic cells. That an efficient cross-priming of autologous CD8(+) cells could be induced by DC pulsed with apoptotic or necrotic LCL but not with cell lysates was further demonstrated in assays of IFN-gamma production in response to short-term re-stimulation of CD8(+) cells with LCL. In addition, LCL-specific CD8(+) cells could specifically lyse autologous DC that had been pulsed with LCL-derived antigens, further suggesting that DC presented exogenous antigens on HLA class I molecules.

Antigen Presentation↗

PubMed2000

Phase II study of combined immunotherapy, chemotherapy, and radiotherapy in the postoperative treatment of advanced non-small-cell lung cancer.

The association of adoptive immunotherapy (AI) and radiotherapy has been shown to be effective in the control of residual intrathoracic disease, while having no systemic advantages, in patients operated on for locally advanced non-small-cell lung cancer (NSCLC). The potential synergy of coupling immunotherapy and chemotherapy has been emphasized in several tumors including NSCLC. The aim of this work was to determine the feasibility and activity of a combined therapeutic program, including AI, chemotherapy, and radiotherapy in patients who had undergone incomplete resections for NSCLC. In a phase II trial, 13 patients received the combined treatment. AI was given from week 4 after surgery until week 8. Concurrent chemo-(cisplatin and etoposide)-radiotherapy (60 Gy) was given from week 9 to week 14. Twenty eligible patients received chemoradiotherapy only and were used as a non-randomized concomitant group for merely descriptive purposes. At 9-month follow-up, 10 of the 13 patients had progression of disease and the study was stopped. Progression-free survival and survival were similar to those of the chemoradiotherapy group. The present study showed that the sequence of immunotherapy followed by chemotherapy is not effective as adjuvant treatment in patients operated on for stage III NSCLC, at least when used according to the adopted schedule.

Adult↗

PubMed2000

Natural killer cells lyse autologous herpes simplex virus infected targets using cytolytic mechanisms distributed clonotypically.

Natural killer (NK) cells have the capability of lysing targets that have down-regulated the expression of HLA class I molecules. Herpes simplex virus (HSV) infection results in a profound reduction of HLA class I molecules on the surface of infected cells. For this reason, NK cell populations kill efficiently HSV-infected cells. The recent availability of a panel of monoclonal antibodies directed to NK receptors for HLA class I (CD158a, CD158b, anti-p70, anti-p140, and CD94) allowed an accurate dissection of the NK cell subpopulations. Using this approach, the relationship between the expression of NK cell receptors and the capability of lysing HSV-infected cell targets was analyzed at the clonal level. NK cell clones were derived from healthy donors, and cytolytic properties were assayed against HSV-infected autologous fibroblasts. NK cell clones, classified according to the expression of natural killer-cell receptors on their surface, displayed a great heterogeneity of cytolytic properties against HSV-infected cells. Nevertheless, a more accurate functional analysis demonstrated not only that HSV infection downregulated the expression of HLA-A and HLA-B and did not modify the expression of HLA-C, but also that NK cell clones expressing the "activating" form of the anti HLA-C NK cell receptor were more cytolytic than other clones. This finding suggests that two different and clonally distributed mechanisms of NK cell activation may be employed by NK cells to kill HSV-infected autologous target cells.

Cells, Cultured↗

PubMed2000

Spontaneous apoptosis in neutrophils is associated with downregulation of HLA Class I and is prevented by ligation of Class I.

In many types of cells, ligation of human leukocyte antigens (HLA) Class I molecules with specific mAbs results in the transduction of signals that trigger different cell functions. We have investigated the effects of Class I ligation in human neutrophils. After several hours in culture, neutrophils split spontaneously into two subpopulations, one with normal and the other with reduced levels of Class I. The latter subpopulation displayed high binding capacity for Annexin V, showed a hypodiploid peak, electrophoretic DNA fragmentation, and morphological features of apoptotic cells. The addition of drugs known to delay apoptosis (GM-CSF or cAMP) resulted in a reduction of Class I modulation. Furthermore, ligation of surface Class I with F(ab')2 fragments of the anti-Class I mAb W6/32 resulted in a delay in the progression of apoptosis. These data indicate that this surface Class I molecule is a marker of age-related apoptosis, and the ligation of these molecules results in the transduction of a signal that inhibits apoptosis. Thus, the downregulation of HLA Class I molecules in aging neutrophils prevents their halting the apoptotic process.

Adult↗