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Biomedical subjects

G Filaci

Publications and source records attributed to G Filaci.

At least 37 records · Page 2Linked to original sources
PubMed1999

Is there a role for NK cells in the pathogenesis of multiple sclerosis? A case study.

We report on a patient with multiple sclerosis (MS) in which we documented an elevated percentage of activated CD56+ natural killer (NK) cells in peripheral blood lymphocytes. NK cells from the patient lysed preferentially glioblastoma but not neuroblastoma cells. Killing of glial cells was not inhibited by a monoclonal antibody against a monomorphic determinant of MHC class I gene products. Lymphokine activated killer (LAK) cell function in the MS patient was comparable to that of controls. Analysis of cytokine production during resting or activated states demonstrated that this patient had a deficit in the ability to secrete T cell derived cytokines associated with increased production of TNFalpha, a product of NK cells. Taken together, these data indicate a possible involvement of NK cells in the pathogenesis of MS.

CD56 Antigen↗
PubMed1999

Cyclosporin A and iloprost treatment of systemic sclerosis: clinical results and interleukin-6 serum changes after 12 months of therapy.

OBJECTIVES: The main aim was to analyse the long-term therapeutic effects on systemic sclerosis (SSc) patients of treatment with either (i) iloprost alone or (ii) low-dose oral cyclosporin A (CyA) associated with iloprost. A secondary aim was to analyse interleukin-6 (IL-6) serum levels in SSc patients before and after 1 yr of treatment. METHODS: A clinical trial was performed in which 20 consecutive SSc patients were alternately randomized into two homogeneous groups receiving either monthly i.v. iloprost (1 ng/kg/min in 6 h i.v. infusion, for 5 consecutive days, 1 week per month) (Group I) or low-dose CyA (2.5 mg/kg/day) associated with iloprost administration (Group II). IL-6 concentrations were evaluated by ELISA in the sera of each patient before and after 1 yr of therapy and in 20 healthy subjects. RESULTS: After 1 yr of therapy, a significant improvement of skin (P=0.008), microvascular (P=0.004) and oesophageal (P=0.05) morphological and functional parameters was observed only in Group II patients. Furthermore, after 1 yr of treatment, a significant reduction (P=0.007) of IL-6 serum concentration was observed only in Group II patients. CONCLUSIONS: Collectively, our data suggest that the combination of low-dose CyA with iloprost administration may be of clinical utility in SSc and that a mechanism of action of CyA in SSc may include the decrease in IL-6 production.

Adolescent↗
PubMed1998

Double-stranded deoxyribonucleic acid binds to HLA class II molecules and inhibits HLA class II-mediated antigen presentation.

CD4+ T cells proliferating in response to purified double-stranded deoxyribonucleic acid (dsDNA) have been recently demonstrated in peripheral blood mononuclear cells of patients with systemic lupus erythematosus. Their activation was inhibited by anti-HLA class II (HLA-II) monoclonal antibodies; thus, the existence of a molecular interaction between dsDNA and HLA-II is conceivable. In this report we show that dsDNA specifically bind to HLA-II. After preincubating cells with purified dsDNA or synthetic oligonucleotides, dsDNA was detected on the cell membrane and in the lysates of HLA-II+ but not of isogenic HLA-II- cell lines. We demonstrate that dsDNA binding inhibits that of a specific peptide to HLA-II. Mixed lymphocyte reaction and antigen-specific T cell proliferation were inhibited by the preincubation of stimulator cells or antigen-presenting cells with dsDNA. These results suggest the existence of a novel mechanism of down-modulation of the CD4+ T cell function generated by lack of stimulation due to the HLA-II presenting molecules being "occupied" by dsDNA.

Animals↗
PubMed1998

Immunoregulatory role of soluble HLA molecules: a new skin for an old subject?

The available evidence suggests that measurement of the level of total sHLA-1 antigens and of donor-derived and recipient-derived allospecificities as well as the characterization of their variants in recipient's serum may provide useful information to differentiate graft rejections from infections in allograft recipients. Moreover, a significant progress has been made in our understanding of the functional properties of sHLA-I antigens in serum and of their potential role in the modulation of immune responses. If these preliminary results will be confirmed, then sHLA-I antigens are likely to become important reagents to monitor and treat graft recipients.

Histocompatibility Antigens Class I↗
PubMed1997

Soluble HLA class I and class II molecule levels in serum and cerebrospinal fluid of multiple sclerosis patients.

Increased concentrations of soluble HLA class I and class II molecules (sHLA-I and sHLA-II) have been observed in infectious, inflammatory, and autoimmune diseases. Because autoimmune mechanisms are considered to play a role in the pathogenesis of multiple sclerosis (MS), we decided to dose sHLA-I and sHLA-II in serum and cerebrospinal fluid (CSF) of MS patients comparing their concentrations with those observed in serum and CSF of patients with other neurologic diseases (OND) without evidence of neuroradiologic involvement of central nervous system (CNS) and in serum of healthy donors. The serum concentrations of sHLA-I were higher in both MS and OND patients than in healthy donors (P < 0.05) whereas sHLA-II serum concentrations were lower in MS patients than in both OND patients and healthy donors (P < 0.01). Detectable amounts of sHLA-II were observed in the CSF of 45% of MS patients and in CSF of only 6% of OND patients (P < 0.001). In MS patients a significant correlation between sHLA-I serum and CSF concentrations was observed (P < 0.01), whereas sHLA-II serum and CSF levels did not correlate. In conclusion, alterations of sHLA-I and sHLA-II serum and CSF concentrations are present in MS patients and could be involved in the induction of enhanced susceptibility to develop MS or in MS pathogenesis.

Adolescent↗
PubMed1997

S-adenosil-L-methionine is able to reverse the immunosuppressive effects of chenodeoxycholic acid in vitro.

The study was conceived to evaluate if S-adenosil-L-methionine, a substance commonly used in the treatment of cholestasis in patients with cirrhosis and chronic hepatitis, exerts any immunological effect and of it is able to counterbalance bile acid-mediated immunosuppression. Proliferation and interleukin 2 and interferon-gamma secretion of human lymphocytes, collected from healthy subjects and exposed to mitogenic stimuli (phytohemagglutinin, pokeweed and anti-CD3 monoclonal antibodies), were analysed in the basal condition or after exposure to S-adenosil-L-methionine and/or chenodeoxycholic acid. Chenodeoxycholic acid inhibited phytohemagglutinin-induced lymphocyte proliferation and interferon-gamma secretion, and phytohemagglutinin and pokeweed-mediated interleukin 2 secretion. S-adenosil-L-methionine did not affect lymphocyte proliferation while it reduced interleukin 2 secretion upon phytohemagglutinin and pokeweed stimulation and interferon-gamma secretion upon all stimuli tested. Moreover, S-adenosil-L-methionine counteracted chenodeoxycholic acid-mediated inhibition of lymphocyte proliferation and interleukin 2 secretion. The results of our study confirm the immunosuppressive role of chenodeoxycholic acid on both secretive and proliferative lymphocyte functions and provide evidence of immunomodulatory activities of S-adenosil-L-methionine and its capacity to antagonize chenodeoxycholic acid-mediated inhibition of lymphocyte proliferation and interleukin 2 secretion.

Antibodies, Monoclonal↗
PubMed1997

Plicometer skin test: a new technique for the evaluation of cutaneous involvement in systemic sclerosis.

This study tries to establish a new method for the evaluation of skin lesion extension and progression in systemic sclerosis (SSc) patients. Plica thickness measurements of 200 healthy subjects and 19 SSc patients by plicometer were performed, and an arbitrary plicometer skin score was created. The plicometer skin score was compared to m-Rodnan's score on the same patients. The statistical association between the plicometer score and DLCO values in SSc patients was analysed. Plicometer plica thickness cut-off values of normality were established for nine skin areas. High specificity (95-99%) and a high negative predictive value (95.5-100%) were found. The sensitivity and the positive predictive value were 52.6-100% and 52.4-90.5%, respectively. The coefficient of variation of the plicometer score (0.05-0.14) was lower than that of the m-Rodnan score (0.22-0.33). A statistically significant association was found between skin score and DLCO. The study underlines the accuracy and reproducibility of the plicometer skin test, and suggests its utility in monitoring scleroderma progression.

Adolescent↗
PubMed1996

Prednisone increases apoptosis in in vitro activated human peripheral blood T lymphocytes.

Glucocorticoid hormones (GCH) regulate, through the apoptotic process, the negative selection of immature T cells in the thymus. Because apoptosis seems to occur also in the maintenance of peripheral tolerance, we have investigated whether GCH may induce apoptosis in human mature lymphocytes. Peripheral blood lymphocytes (PBL) or peripheral CD4(+) and CD8(+) T cell subsets were cultured in the presence of phytohaemaglutinin (PHA) or PHA and prednisone (PDN) at 10(-3)-10(-12)M concentrations for 72, 96 and 120h. Cell cycle and membrane antigen expression were evaluated by flow cytometry and DNA degradation was detected by agarose gel electrophoresis. PDN blocks PBL growth in the G1 phase of cell cycle and inhibits both IL-2 receptor (IL-2R) expression and IL-2 secretion. Apoptosis is clearly increased by PDN in PHA-activated human PBL, and the apoptotic effect of PDN is stronger on CD8(+) than on CD4(+) T lymphocytes. All these effects are dose- and time-dependent. The addition of exogenous IL-2 did not rescue lymphocytes from PDN-increased apoptosis. These results show that PDN increases apoptosis in mature activated human peripheral blood lymphocytes, suggesting a possible role of GCH in the maintenance of immune tolerance at post-thymic level.

Adult↗
PubMed1995

Major histocompatibility complex class I-restricted presentation of influenza virus nucleoprotein peptide by B lymphoma cells harboring an antibody gene antigenized with the virus peptide.

We analyzed the capacity of B cells to process and present a peptide from the variable region of an endogenous immunoglobulin heavy (H) chain to a major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocyte (CTL) clone. The H-chain gene was engineered to express 14-amino acid peptide from the sequence of the influenza virus nucleoprotein (NP) antigen in the third complementarity-determining region (CDR3). This NP peptide is presented in association with the Db allele in H-2b mice. We demonstrate that B lymphoma cells (H-2b) harboring the antigenized H-chain gene process and present the NP peptide in association with the Db molecule and are lysed by a CTL clone specific for that peptide in an MHC-restricted way. In contrast, the soluble antigenized antibody failed to mediate lysis of H-2b target cells. The endogenously processed immunoglobulin CDR3 peptide could be eluted from surface Db molecules in transfected cells. This study formally demonstrates that peptides from the hypervariable loops of endogenous immunoglobulin are processed through the endogenous degradative pathway and are presented to CD8+ T cells in the context of MHC class I molecules. The implication of these findings for processing and presentation of endogenous immunoglobulin peptides in B cells and network regulation by idiopeptides is discussed.

Amino Acid Sequence↗
PubMed1995

CD4+ Th0 cell clones, isolated from a metastatic lymph node of a melanoma patient, possess cytolytic function.

In the present study T lymphocytes isolated from a metastatic lymph node (T-LNL) of a melanoma patient have been cloned. In the attempt to verify whether T-LNL may acquire in vitro functional activities in the absence of tumour-associated antigens, they were cloned utilizing allogenic lymphocytes as feeder cells. Nineteen clones generated from T-LNL proved to be CD4+ and, among these, five were able to kill autologous and allogeneic human melanoma cells in HLA-class-II-restricted way. On the basis of their cytokine production, these CD4+ cytolytic T-LNL clones were shown to belong to the Th0 subset and three of them expressed the V beta 17 chain of the T cell receptor. These results suggest the presence of melanoma-specific but functionally inactive lymphocytes with T cell receptor oligoclonality in the lymph node environment. These specific T cells may acquire in vitro the capacity to kill autologous and allogeneic tumours without any induction by autologous melanoma cells.

CD4-Positive T-Lymphocytes↗
PubMed1995

Interferons up-regulate with different potency HLA class I antigen expression in M14 human melanoma cell line. Possible interaction with glucocorticoid hormones.

The relative potency of interferon alpha (IFN alpha), interferon beta (IFN beta), and interferon gamma (IFN gamma) in inducing the expression of HLA class I antigens, as well as their capacity to counteract the inhibition induced by glucocorticoid hormones on HLA class I antigen expression, were analysed in the human melanoma cell line M14, both at membrane and at mRNA level. The data obtained indicate that (a) IFN enhance with different potency (IFN gamma > IFN beta > IFN alpha) the expression of HLA class I antigens in M14 cells, (b) prednisone inhibits HLA class I antigen expression, (c) glucocorticoid hormones, when associated with IFN alpha or IFN gamma, inhibit the HLA class I enhancement induced by IFN alone, and, finally, (c) the association between 1 microM prednisone or 1 microM deflazacort and IFN beta seems to potentiate the enhancing capacity of IFN on the expression of HLA class I molecules at the mRNA level. These findings, if confirmed, might indicate that IFN and glucocorticoid hormones are not mutually exclusive in the management of human melanoma.

Drug Synergism↗
PubMed1995

Increased serum concentration of soluble HLA-DR antigens in HIV infection and following transplantation.

HLA class I and class II antigens circulate in serum as soluble molecules. Increased concentrations of soluble HLA class I molecules have been demonstrated in viral diseases, in rejection episodes following organ transplantation and in graft versus host disease. To explore the possibility of a variation of the serum concentrations of soluble HLA class II molecules in the same pathologic conditions we developed a double determinant immune assay that detects whole soluble HLA-DR molecules (sHLA-DR). The mean level of sHLA-DR antigens in sera from 23 healthy individuals was 0.64 +/- 0.72 microgram/ml. Elevated serum concentrations of sHLA-DR molecules were detected in sera from HIV infected patients in CDC2/3 and in CDC4 C1 stages (2.0 +/- 1.7 micrograms/ml and 4.6 +/- 1.7 micrograms/ml, respectively), in sera from patients affected by acute rejection after liver transplantation (5.3 +/- 3.7 micrograms/ml) and in sera from patients affected by severe acute graft versus host disease following bone marrow transplantation (8.8 +/- 3.1 micrograms/ml). The increase of sHLA-DR molecules in these sera significantly correlated with the elevation of soluble HLA class I antigens (P = 0.0004). The reported data suggest that both soluble HLA class I and class II molecules serum levels increase during viral infections and strong immune reactions and could suggest the involvement of these molecules in immunoregulation.

Bone Marrow Transplantation↗
PubMed1994

Immune cell circulating subsets are affected by gonadal function.

Influence on the immune system activity by sex hormones has been widely reported. Fertile women are proner to the onset of autoimmune diseases than men, but this increased susceptibility disappears after menopause. The hormonal changes are very likely to be responsible for this event, but precise correlations between sex hormone levels and immune functions have not been defined. For this reason we have analyzed phenotype and natural cytotoxicity of peripheral blood lymphocytes (PBL) from 35 women in menopause, comparing them with the same parameters of 28 fertile and 8 postmenopausal women and correlating them with the hormonal pattern of each group. We have also considered 8 women with premature menopause. Hormonal levels have been detected by radioimmune assays, while PBL phenotype has been studied by immunofluorescence and FACS analysis. The natural killer (NK) cell activity has been calculated on the basis of a chromium release assay. Postmenopausal women showed a reduction of the number of total lymphocytes (1650 +/- 215 cells/mmc) in comparison to fertile women (2081 +/- 200 cells/mmc, P < 0.01). The decrease mainly involved B and CD4+ T lymphocyte subpopulations (P < 0.05 and P < 0.01, respectively). Women with premature menopause had lower percentage of CD4 lymphocytes (34% vs 47%, P < 0.01) and higher percentage of CD8 (30% vs 22%, P < 0.02) and NK cells (32% vs 14%, P < 0.009) than fertile women of the same age. The percentage of circulating lymphocytes expressing HLA class II antigens also resulted as being increased (22% vs 9%, P < 0.01). The number of total, CD2, CD4 T lymphocytes, B and NK cells correlated positively with LH and negatively with FSH serum levels (P < 0.05 and P < 0.002, respectively). PRL positively influenced CD2, CD4 and B lymphocyte numbers (P < 0.001). FSH and 17 beta-estradiol inversely affected CD8 and B lymphocyte numbers (P < 0.005 and P < 0.02, respectively). In conclusion, the increase of FSH and the decrease of PRL levels appear to be involved in the reduction of B and CD4 T lymphocytes thus lowering the risk for the onset of autoimmune diseases during and after menopause. Generalized activation of the immune system (raised expression of HLA class II antigens) with elevated numbers of cytotoxic subpopulations (CD8 and NK lymphocytes) is present in women affected by premature menopause suggesting the involvement of autoimmune dysregulation in the pathogenesis of this syndrome.

Adult↗
PubMed1993

Expression of conformationally constrained adhesion peptide in an antibody CDR loop and inhibition of natural killer cell cytotoxic activity by an antibody antigenized with the RGD motif.

We report that an antibody engineered to express three Arg-Gly-Asp (RGD) repeats in the third complementarity-determining region of the heavy chain (antigenized antibody) efficiently inhibits the lysis of human erythroleukemia K-562 cells by natural killer (NK) cells. Synthetic peptides containing RGD did not inhibit. Inhibition was specific for the (RGD)3-containing loop and required simultaneous occupancy of the Fc receptor (CD16) on effector cells. The antigenized antibody inhibited other forms of cytotoxicity mediated by NK cells but not cytotoxicity mediated by major histocompatibility complex-restricted cytotoxic T lymphocytes (CTL). A three-dimensional model of the engineered antibody loop shows the structure and physicochemical characteristics probably required for the ligand activity. The results indicate that an RGD motif is involved in the productive interaction between NK and target cells. Moreover, they show that peptide expression in the hypervariable loops of an antibody molecule is an efficient procedure for stabilizing oligopeptides within a limited spectrum of tertiary structures. This is a new approach towards imparting ligand properties to antibody molecules and can be used to study the biological function and specificity of short peptide motifs, including those involved in cell adhesion.

Amino Acid Sequence↗
PubMed1993

Immunotherapy with intralesional and systemic interleukin-2 of patients with non-small-cell lung cancer.

Eight patients affected by non-small-cell lung cancer were treated with intralesional and systemic recombinant IL-2 (rIL-2) injection with the aim of activating both tumour-infiltrating lymphocytes and circulating cytotoxic or killer cells. The schedule of treatment was as follows: a daily fine-needle transparietal intralesional rIL-2 injection (1 x 10(5) Cetus units) from day 1 to day 5 and systemic rIL-2 infusion (1 x 10(5) Cetus units kg-1 day-1) from day 6 to day 10. One to four cycles of treatment were received by each patient. Clinical and immunological evaluations were performed (a) before treatment, (b) following the intralesional rIL-2 administration, (c) 1 h after the beginning of rIL-2 infusion and (d) at the end of the systemic rIL-2 infusion. No complete remission was achieved, two patients showed a partial remission, three resulted in stable disease and three patients progressed. Natural killer and lymphokine-activated killer cell activity dramatically decreased 1 h after the beginning of rIL-2 infusion and increased at the end of treatment. A progressive increase of circulating CD8+ and HLA class II+ T cells as well as of CD8+ T cell clones, most of which displayed NK activity, was recorded following rIL-2 infusion. Present data indicate that (a) the local administration of rIL-2 coupled with systemic rIL-2 infusion may be suggested as an alternative approach for the immunotherapy of lung cancer, (b) rIL-2 induces different immunological modifications according to the route and the time of its administration and (c) rIL-2 administration increases the amount of circulating immune cells with potential antitumour activity.

Carcinoma, Non-Small-Cell Lung↗