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Biomedical subjects

M Alessio

Publications and source records attributed to M Alessio.

At least 19 recordsLinked to original sources
PubMed2006

Clinical and genetic characterization of Italian patients affected by CINCA syndrome.

OBJECTIVE: We report the experience of the Italian Registry of patients affected by chronic infantile neurological, cutaneous, articular (CINCA) syndrome. The clinical and genetic features of 12 unrelated Italian patients with CINCA syndrome are described, focusing on the possible influence of the presence of CIAS1/cryopyrin mutations on the phenotype of the disease and on its prognosis. METHODS: The clinical features of 12 Italian CINCA patients were evaluated. Genomic DNA of the patients was sequenced using specific primers for CIAS1 and ASC genes. RESULTS: Our patients shared typical CINCA characteristics and, sometimes, remarkable perinatal events, peculiar of CIAS1-mutated patients. Seven patients carried CIAS1 missense mutation, localized within the nucleotide binding domain of cryopyrin. Four previously described mutations and three new heterozygous CIAS1 missense mutations were identified. ASC gene, encoding for a direct interactor of cryopyrin, was not mutated in Italian CINCA patients. Finally, we reported the efficacy and safety of anti-IL1 therapy (Anakinra) in seven patients with a particularly severe CINCA phenotype. CONCLUSION: Despite some common signs-used as syndrome hallmarks-we observed a high variability in symptoms, genetic results and outcomes in Italian CINCA patients. In contrast with other authors, we cannot find out any correlation between mutations in CIAS1 and CINCA severity, but we underlined the concomitance of perinatal events and mental retardation only in CIAS1 mutated subjects. Finally, we confirmed the efficacy of Anakinra treatment, both in CIAS1-mutated and non-mutated patients.

Adolescent↗
PubMed2006

ZAP-70 is expressed by normal and malignant human B-cell subsets of different maturational stage.

ZAP-70 tyrosine kinase is involved in signalling pathways following T-cell receptor stimulation and was originally described only in T cells and natural killer cells. ZAP-70 expression has been reported in normal mouse B lineage cells and in human malignant B lymphocytes, mainly in chronic lymphocytic leukemia (CLL) where it correlates with clinical outcome. We analyzed several B-cell lines and ex vivo malignant B cells, ranging from acute lymphoblastic leukemia to multiple myeloma and reflecting different stages of B-cell differentiation, and they showed ZAP-70 expression regardless their maturation stage. We then analyzed by Western blot and flow cytometry different human normal B-lymphocyte subpopulations: naïve, germinal center and memory B cells from tonsils, CD19+ CD5+ cells from cord blood and CD19+ lymphocytes from peripheral blood. All expressed ZAP-70 protein, though at different levels depending on their differentiation, activation and tissue localization. In addition, ZAP-70 expression levels could be modulated following stimulation via the B-cell receptor. These findings implicate a potential role of ZAP-70 in the signalling pathway of B lymphocytes at different maturational stages, indicate that ZAP-70 expression is not a CLL-specific feature among B-cell malignancies and suggest that the absence of ZAP-70 rather than its presence should be considered abnormal for malignant B lymphocytes.

Antigens, CD↗
PubMed2001

Cytoadherence of Plasmodium falciparum-infected erythrocytes is mediated by a redox-dependent conformational fraction of CD36.

The adherence of Plasmodium falciparum-infected RBC (IRBC) to postcapillary venular endothelium is an important determinant of the pathogenesis of severe malaria complications. Cytoadherence of IRBC to endothelial cells involves specific receptor/ligand interactions. The glycoprotein CD36 expressed on endothelial cells is the major receptor involved in this interaction. Treatment of CD36-expressing cells with reducing agents, such as DTT and N-acetylcysteine, was followed by CD36 conformational change monitorable by the appearance of the Mo91 mAb epitope. Only a fraction of the surface expressed CD36 molecules became Mo91 positive, suggesting the presence of two subpopulations of molecules with different sensitivities to reduction. The Mo91 epitope has been localized on a peptide (residues 260-279) of the C-terminal, cysteine-rich region of CD36. Treatment with reducing agents inhibited the CD36-dependent cytoadherence of IRBC to CD36-expressing cells and dissolved pre-existent CD36-mediated IRBC/CD36-expressing cell aggregates. CD36 reduction did not impair the functionality of CD36, since the reactivity of other anti-CD36 mAbs as well as the binding of oxidized low density lipoprotein, a CD36 ligand, were maintained. The modifications induced by reduction were reversible. After 14 h CD36 was reoxidized, the cells did not express the Mo91 epitope, and cytoadherence to IRBC was restored. The results indicate that IRBCs bind only to a redox-modulated fraction of CD36 molecules expressed on the cell surface. The present data indicate the therapeutic potential of reducing agents, such as the nontoxic drug N-acetylcysteine, to prevent or treat malaria complications due to IRBC cytoadhesion.

Acetylcysteine↗
PubMed2000

CD36 is a ditopic glycoprotein with the N-terminal domain implicated in intracellular transport.

The CD36 receptor sequence predicts two hydrophobic domains located at the N- and C-termini of the protein, but there are conflicting reports as to whether the N-terminal uncleaved leader sequence functions as a transmembrane domain. To investigate the topology of CD36, we generated a panel of mutants lacking either one or both hydrophobic regions and analyzed their folding and transport in COS-7 cells. The N- and the C-terminal hydrophobic regions were both sufficient to anchor CD36 in the membrane, and a FLAG epitope inserted at the N-terminus was located intracellularly. These results indicate that CD36 adopts a ditopic configuration. Accordingly, neither N- nor C-terminal truncation mutants were secreted. Analysis with conformation-specific monoclonal antibodies showed that the N-terminal transmembrane domain truncated molecule was slowly transported through the exocytic pathway and largely accumulated intracellularly. Thus, dual membrane insertion dictates the correct topogenesis and seems to be necessary for efficient folding and intracellular transport.

Amino Acid Sequence↗
PubMed2000

Clustering of distinct autoimmune diseases associated with functional abnormalities of T cell survival in children.

To ascertain whether alterations of lymphocyte switching off may be associated with clustering of autoimmune diseases in children, Fas- and C2-ceramide-induced cell death was evaluated on T cell lines derived from three patients affected by clustering of autoimmune disorders. Three patterns were found: patient 3 was resistant to Fas- and C2-ceramide, patient 1 was resistant to Fas, but sensitive to C2-ceramide, patient 2 was resistant to C2-ceramide, but sensitive to Fas. By contrast, Fas- and C2-ceramide-induced cell death was normal in five children with systemic juvenile rheumatoid arthritis, five children with insulin-dependent diabetes and 10 age-matched healthy controls. Surface expression of Fas was low in patient 1, but normal in patients 2 and 3. Together with normal Fas transcripts, patients 2 and 3 displayed a transcript 152 bp longer than the normal one retaining intron 5. Our data indicate that polyreactive autoimmune syndromes may be associated with heterogeneous alteration of the immune response switching-off system.

Adolescent↗
PubMed2000

Simultaneous peripubertal onset of multireactive autoimmune diseases with an unusual long-lasting remission of type 1 diabetes mellitus.

Although it is well known that patients with type 1 diabetes mellitus are susceptible to other autoimmune diseases, the simultaneous occurrence of clustered distinct autoimmune diseases is uncommon. We report a 16-year-old girl, previously diagnosed as having coeliac disease and IgA deficiency, who at 13 years of age developed a clustering of distinct autoimmune diseases, including type 1 diabetes mellitus, rheumatoid arthritis (RA) and euthyroid autoimmune thyroiditis, eventually resulting in a simultaneous long-term remission. The clinical picture was associated with a functional immunodeficiency characterized by a defect in proliferative responses to T cell predominant mitogens and a normal response to the B cell predominant mitogen. In addition, the T cell activation markers HLA-DR, IL-2 receptor and transferrin receptor) were not upregulated. The clinical course of this immunodeficiency paralleled the outcome of the autoimmune diseases. After the abrupt onset, spontaneous clinical remission of both diabetes mellitus and RA was observed. Insulin was first reduced in dose and then discontinued completely at 15 months, in the presence of normal C peptide secretion and normal metabolic control (HbA1c 5.8%). Anti-glutamate decarboxylase (GAD65) and anti-IA-2 antibodies remained persistently high. During the remission phase a normalization of the functional immune defect was observed. The gradual resolution of the multisystemic diseases as well as the normalization of immune function in our patient is unusual. This case may be of considerable value in furthering our knowledge of the immunological mechanisms implicated in these rare multireactive syndromes.

Adolescent↗
PubMed2000

CD36 folding revealed by conformational epitope expression is essential for cytoadherence of Plasmodium falciparum-infected red blood cells.

CD36 is a membrane glycoprotein and a putative scavenger receptor expressed by several cell types. In capillary endothelial cells, it mediates the adherence of erythrocytes infected with Plasmodium falciparum. The CD36 sequence contains two hydrophobic domains located at the amino-and carboxyl-termini of the protein, but the topology of this protein and the functional significance of these domains are still not clearly defined. We generated soluble CD36-IgG chimeric molecules by fusion of the extracellular domains of CD36 with human immunoglobulin domains. The construct containing the N-terminal hydrophobic domain of CD36 was completely retained intracellularly as membrane-associated molecule, suggesting that the N-terminal hydrophobic domain of the CD36 is a real transmembrane domain and that CD36 has hairpin topology. A small amount of the CD36-IgG chimeric construct lacking both transmembrane domains escaped retention, was correctly processed, and accumulated in the extracellular medium as a soluble molecule. This CD36-IgG construct failed to bind Plasmodium falciparum-infected erythrocytes. Using monoclonal antibodies specific for either conformational or structural epitopes, we demonstrate that failure of this CD36-IgG construct to bind infected erythrocytes was due to incorrect folding of the soluble chimeric molecule.

Animals↗
PubMed2000

Methionine 156 in the immunodominant domain of CD36 contributes to define the epitope recognized by the NL07 MoAb.

CD36 is a membrane glycoprotein expressed by several cell types, and play a role as a receptor for different physiological and pathological ligands. An immunodominant domain of CD36 has been described in the amino acidic region 155-183, where many ligands and monoclonal antibodies (MoAbs) react. MoAbs against CD36 have proved useful in structural as well as functional studies. One of these antibodies, MoAb NL07, recognizes a conformational epitope that is acquired in the late steps of the CD36 maturation. The NL07 epitope appears to be functionally relevant and blocks CD36-mediated binding to red blood cells infected with the malaria parasite Plasmodium falciparum (IRBC). In this work a mutant COS-7 clone expressing NL07-negative CD36 molecules on the cell surface was investigated. In the mutant, the methionine in position 156 of the wild type CD36 sequence was replaced by a valine. It was determined that methionine 156 was essential for NL07 reactivity, mapping the NL07 epitope to the vicinity of the functionally important immunodominant domain (aa 155-183) of CD36. Although methionine 156 is located in this region, the CD36V156 mutated molecule was apparently functional and able to bind IRBC and oxidized LDL.

Amino Acid Sequence↗
PubMed1999

Very large amounts of peripheral blood progenitor cells eliminate severe thrombocytopenia after high-dose melphalan in advanced breast cancer patients.

We analyzed the relationship between the reinfusion of large or very large amounts of peripheral blood progenitor cells (PBPC) and hematologic toxicity in twenty-one advanced breast cancer patients subjected to a myeloablative dose of melphalan at the end of a high-dose sequential chemotherapy (HDSC) program. We also evaluated the influence of the white blood cell (WBC) count to predict an optimal PBPC harvest after high-dose chemotherapy and growth factor priming. Twenty-one patients with high-risk or metastatic breast cancer sequentially received: high-dose cyclophosphamide (HD-Cy) and G-CSF followed by PBPC harvest, HD-methotrexate plus vincristine, HD-doxorubicin, cisplatin and finally HD-melphalan 200 mg/m2 (HD-L-PAM) followed by PBPC reinfusion. No growth factor was administered after HD-L-PAM. CD34+ cytofluorimetric analysis, WBC count and clonogenic assays were employed to monitor circulating cells and to analyze the PBPC harvest. Correlation between different PBPC doses and hematologic toxicity as well as leukocyte and platelet recovery time was attempted. Patients received a median number of 16 (4-25.1) x 10(6)/kg CD34+ cells, 81.3 (30.8-228) x 10(4)/kg CFU-GM and 4.2 (1.3-7.3) x 10(8)/kg nucleated cells (NC) after HD-L-PAM. The number of days with fewer than 1 x 10(9)/l leukocytes and 20 x 10(9)/l platelets were 6 (range 4-9) and 0 (range 0-3), respectively. The CD34+ cell dose significantly correlated with both platelet count nadir (r = 0.73) and time to 50 x 10(9)/l platelets (r = 0.7), but did not correlate with time to reach more than 1 x 10(9)/l WBC count (r = 0.2). In particular, we found that in 12 patients given very large amounts of CD34+ cells, ranging between 15.8 and 25. 1 x 10(6)/kg (V-LA-CD34+), the platelet nadir count never fell below 20 x 10(9)/l and platelet transfusions were not required. Conversely, nine patients who received only large amounts of CD34+ cells, ranging between 4 and 12 x 10(6)/kg (LA-CD34+), experienced a platelet nadir lower than 20 x 10(9)/l and required 2 days (range 1-4) to achieve independence from platelet transfusions (P = 0.001 and P = 0. 0005). The requirement for packed red blood cells (RBC) was 1.5 vs 3 units in the V-LA-CD34+ and LA-CD34+ groups respectively (P = 0.063). The analysis of 44 PBPC collections demonstrated that 29 aphereses performed with a WBC count <20 x 10(9)/l yielded a mean of 312 +/- 43 x 10(6) CD34+ cells and 1831 +/- 201 x 10(4) CFU-GM, whereas 15 collections performed with WBC count >20 x 10(9)/l yielded 553 +/- 64 x 10(6) CD34+ cells and 3190 +/- 432 x 10(4) CFU-GM (P = 0.004). In conclusion, our data suggests that V-LA-CD34+ eliminates severe thrombocytopenia and platelet transfusion requirements in breast cancer patients subjected to HD-L-PAM, and higher PBPC collections seems to coincide with WBC count higher than 20 x 10(9)/l after HD-Cy and G-CSF mobilization. These results justify a prospective study to establish whether large doses of CD34+ cells result in significant clinical benefits.

Adult↗
PubMed1999

Responsiveness of outcome measures in juvenile chronic arthritis. Italian Pediatric Rheumatology Study Group.

OBJECTIVE: To examine the responsiveness of the disease activity measures more commonly used in juvenile chronic arthritis (JCA) clinical trials. METHODS: Data were obtained from an open-label, non-controlled, multicentre trial designed to investigate the efficacy of methotrexate (MTX) in children with JCA. Outcome measures, including physician and parent global assessments, functional ability measures, articular variables, and laboratory indicators of systemic inflammation, were assessed at baseline and after 6 months of MTX treatment in 132 patients. Responsiveness of endpoint variables was evaluated by assessing the effect size (ES) and the standardized response median (SRM). RESULTS: Physician and parent global assessments were the more responsive instruments, showing ES and SRM above 1.0. Erythrocyte sedimentation rate, C-reactive protein, functional status measures and articular variables showed intermediate responsiveness. Morning stiffness, haemoglobin and platelet count were the least responsive instruments. CONCLUSION: The results of our analysis indicate that subjective estimations of the disease activity, either by the physician or parents, are the most responsive instruments in the assessment of the therapeutic response in children with JCA. The responsiveness of outcome measures in JCA should be further investigated in prospective controlled studies.

Adolescent↗
PubMed1998

Primary ex vivo culture of keratinocytes isolated from hypertrophic scars as a means of biochemical characterization of CD36.

The CD36 antigen is a molecule which is ectopically expressed on epidermal keratinocytes of hypertrophic scars and is a good candidate for a marker for a broad range of skin pathologies. Most marker studies have been performed using immunohistochemical techniques on fixed skin sections. Our aim was to investigate the biochemical features of the CD36 expressed in pathological keratinocytes and to find an in vitro model for the study of the regulation of its expression. Here we show how keratinocytes isolated from hypertrophic scars can be cultivated in vitro and employed as a model for the study of these cells. We demonstrated that the antigenic features of the CD36 expressed on keratinocytes of hypertrophic scars are identical to those described for the CD36 expressed by other cell types. The molecule was expressed on the surface of keratinocytes which were non-adherent in vitro. Adherent and proliferating keratinocytes, as well as normal keratinocytes, were CD36 negative both at the surface and intracellularly. The in vitro proliferating cells from hypertrophic scars, but not the normal keratinocytes, showed intracellular expression of CD36 after long-term culture and cell stratification, suggesting a regulated expression of CD36 in pathological keratinocyte differentiation.

Adult↗
PubMed1998

Phagocytosis of the malarial pigment, hemozoin, impairs expression of major histocompatibility complex class II antigen, CD54, and CD11c in human monocytes.

In Plasmodium falciparum malaria, large proportions of resident macrophages and circulating monocytes and leukocytes contain massive amounts of the malarial pigment, hemozoin. Previous studies have shown that important functions (e.g., the generation of the oxidative burst, the ability to repeat phagocytosis, and protein kinase C activity) were severely impaired in hemozoin-loaded monocytes. Expression of membrane antigens directly involved in the immune response and in the phagocytic process, and/or under protein kinase C control, in hemozoin-loaded human monocytes was studied. Expression of major histocompatibility complex (MHC) class II after gamma interferon stimulation was blocked in hemozoin-loaded monocytes at the protein expression and gene transcription levels but was preserved in control monocytes loaded with opsonized latex beads or anti-D(Rho)-immunoglobulin G (IgG)-opsonized human erythrocytes. Expression of CD54 (intracellular adhesion molecule 1) and CD11c (p150,95 integrin) was also decreased in hemozoin-loaded monocytes. Expression of MHC class I, CD16 (low-affinity Fc receptor for aggregated IgG), CD32 (low-affinity Fc receptor for aggregated IgG), CD64 (high-affinity receptor for IgG), CD11b (receptor for complement component iC3b [CR3]), CD35 (receptor for complement components C3b and C4b [CR1]), and CD36 (non-class-A scavenger receptor) was not specifically affected by hemozoin loading. These results suggest that hemozoin loading may contribute to the impairment of the immune response and the derangement of antigen presentation reported in previous studies of P. falciparum malaria.

Adult↗
PubMed1998

Performance of the preliminary definition of improvement in juvenile chronic arthritis patients treated with methotrexate. Italian Pediatric Rheumatology Study Group.

OBJECTIVE: To investigate the performance of the core set of outcome measures and the preliminary definition of improvement (PDI) in the assessment of response to methotrexate (MTX) treatment in children with juvenile chronic arthritis (JCA). METHODS: Data were obtained from an open label, non-controlled trial designed to investigate the efficacy of MTX in children with JCA. All patients had the core set of variables assessed at baseline and after six months of treatment. Variables in the core set are: (1) physician global assessment of disease activity; (2) parent or patient (if appropriate in age) global assessment of overall well being; (3) functional ability; (4) number of joints with active arthritis; (5) number of joints with limited range of motion; (6) erythrocyte sedimentation rate. The PDI specifies that to be classified as improved, a patient must show at least 30% improvement from baseline in three of any six variables in the core set, with no more than one of the remaining variables worsening by more than 30%. RESULTS: A total of 111 JCA patients were included in the study. According to the PDI, after six months of MTX treatment 73 patients (66%) were classified as improved and 38 (34%) as not improved. Among the core set variables, parent assessment detected the highest percentage of patients improved (72%) and functional assessment the lowest (37%). CONCLUSION: The PDI identifies about two thirds of patients with JCA treated with low dose MTX as improved. This proportion is similar to that expected to improve based upon a previous controlled study of low dose, oral MTX and provides preliminary evidence of the definition's validity.

Adolescent↗
PubMed1997

Formation of one or more intrachain disulphide bonds is required for the intracellular processing and transport of CD36.

In monocytes/macrophages, CD36 is thought to have a role as a scavenger receptor, mediating the phagocytosis of apoptotic cells and the endocytic uptake of oxidized low-density lipoproteins and fatty acids. The proposed topology of CD36 predicts that, of ten cysteine residues, six lie in the extracellular domain, whereas four are equally distributed in the two short terminal tails flanking the N-terminal and C-terminal hydrophobic stretches. Here we investigate the formation of intrachain disulphide bonds, on the basis of the assumption that the cysteine residues present in the luminal domains are generally oxidized, whereas those in the cytosol are reduced. As revealed by gel mobility-shift assays, disulphide bonds are present in the extracellular domain of the CD36 molecule. The formation of these bonds is required for the transport of CD36 from endoplasmic reticulum to Golgi. Furthermore reactive thiol groups are present in the CD36 sequence, which upon lysis form an intrachain extra loop as an artifact. This disulphide bond is not formed in either (1) truncated CD36 lacking the two C-terminal cysteine residues or (2) Triton X-100-insoluble wild-type CD36 molecules, suggesting that, in this fraction, the C-terminal thiol groups are modified.

Biological Transport↗
PubMed1997

Middle ear involvement in children with chronic rheumatoid juvenile arthritis.

In a selected sample of patients affected by juvenile rheumatoid arthritis (JRA) little is known about middle ear involvement, even though many synovial joints are affected. Multifrequency tympanometry was used to measure admittance, conductance, susceptance and phase angle at different probe frequencies and resonant frequencies. In all, 35 children with JRA and a control group (30 children) were studied. Findings showed that mean resonant frequency values in all children with JRA were greater than in the control children. The multifrequency tympanometry parameters measured in acute JRA subjects are not different from parameters of remission JRA subjects except for a change in the phase angle. The changes found are due to involvement of the incudomalleolar and incudostapedial joints.

Acoustic Impedance Tests↗
PubMed1997

Growth retardation in non-steroid treated juvenile rheumatoid arthritis.

Growth in height was studied in 58 patients with juvenile rheumatoid arthritis (JRA) followed for 4.9 +/- (SD) 2.8 years, who had never received steroids. Height measurements were converted to Height Z Scores. Height Z scores at first and at last visit were respectively 0.7 +/- 1 and 0.7 +/- 0.9 (NS) in pauciarticular, 0 +/- 1.6 and -0.55 +/- 1.6 (p = 0.045) in systemic, 0.29 +/- 0.8 and -0.4 +/- 1 (p = 0.0001) in polyarticular JRA patients. In systemic and polyarticular patients a significant negative relation was found between the duration of disease and the delta Height Z score (p = 0.0008) as well as between the sum of the periods of active disease and the delta Height Z score (p = 0.0001). The patients with functional class = 1 lost 0.01 +/- 0.19 Height Z score per year while those with functional class > or = 2 lost 0.16 +/- 0.13 Height Z score per year (p = 0.005). The loss of Height Z score in systemic and polyarticular subjects observed during pubertal age (-0.71 +/- 0.67 Height Z score) was significantly (p = 0.02) greater than in those observed before puberty (-0.1 +/- 0.72). The longer duration of disease, the higher degree of functional joint involvement, and the age of puberty appear to be risk factors for height growth impairment in systemic and polyarticular JRA.

Adolescent↗
PubMed1996

Synthesis, processing, and intracellular transport of CD36 during monocytic differentiation.

CD36 is an integral membrane glycoprotein expressed by several cell types, including endothelial cells of the microvasculature, erythrocytes, platelets, and monocytes. In the monocytic lineage, CD36 is expressed during the late stages of differentiation in the bone marrow, in circulating monocytes, and in some tissue resident macrophages, and it is thought to mediate the phagocytosis of apoptotic cells and the endocytic uptake of modified lipoproteins. Here we analyze the synthesis, processing, and intracellular transport of CD36 in U937 and THP-1, two human cell lines representing different stages of monocytic maturation. In both cell lines, phorbol 12-myristate 13-acetate induces the expression of CD36. A 74-kDa intracellular precursor is first synthesized that has the hallmarks of a resident protein of the endoplasmic reticulum. The precursor protein is later processed into a mature form of 90-105 kDa which is transported to the cell surface. The kinetics of processing differ significantly in U937 and THP-1. These differences are specific for the CD36, as two unrelated proteins (CD11b and CD45R) are processed and transported to the surface at similar rates in the two cell lines. A 33-kDa endoglycosidase H-sensitive glycoprotein specifically associates with the 74-kDa precursor. Coprecipitation of gp33 correlates with slow processing of CD36 precursor, suggesting that gp33 may play a role in regulating the intracellular transport of CD36, during monocyte maturation.

Antibodies, Monoclonal↗