Biomedical subjects

Giorgio Fassina

Publications and source records attributed to Giorgio Fassina.

6 recordsLinked to original sources

PubMed2006

Progressive increase of SCCA-IgM immune complexes in cirrhotic patients is associated with development of hepatocellular carcinoma.

About 3-4% of cirrhotic patients develop primary liver cancer every year. Specific serologic markers have not yet been identified for screening of high risk patients. The serpin squamous cell carcinoma antigen (SCCA) is overexpressed in liver cancer and circulating SCCA-IgM complexes have been described in patients with hepatocellular carcinoma (HCC). The aim of the present study was to assess the behavior of SCCA-IgM in relation to HCC development in patients with cirrhosis. A retrospective, longitudinal study was conducted in a cohort of prospectively followed cirrhotic patients. Two groups with similar clinical profile at presentation were studied : group A included 16 patients who developed HCC during a median follow up of 4 years; group B included 17 patients who did not develop HCC during the same time interval. Circulating SCCA-IgM immune complexes were determined using a recently standardized ELISA assay. At presentation similar levels of SCCA-IgM complexes [mean +/- SD: 267.40 +/- 382.25 U/ml vs. 249.10 +/- 446.90 U/ml, p = 0.9006] and of alpha-fetoprotein [AFP; 24.11 +/- 59.04 IU/ml vs. 10.91 +/- 23.34 IU/ml, p = 0.3995] were detected in group A and in group B. The increase over time (phi) of SCCA-IgM, assessed within at least one year before clinical diagnosis of HCC, was remarkably higher in group A than in group B (mean +/- SD = 280.05 +/- 606.71 (U/ml)/year vs. -37.92 +/- 95.94 (U/ml)/year, p = 0.0408), while AFP increase was not significantly different (11.89 +/- 23.27 (IU/ml)/year vs. 3.67 +/- 11.46 (IU/ml)/year, p = 0.2179). Receiver operating characteristic (ROC) curves were plotted for the rate of change in the levels of both markers and the diagnostic accuracy measured as AUROC was higher for SCCA-IgM phi (0.821) than for AFP phi (0.654). In conclusion, the progressive increase of SCCA-IgM over time was associated with liver tumor development, suggesting that monitoring the behavior of SCCA-IgM might become useful to identify cirrhotic patients at higher risk of HCC development.

Aged↗

PubMed2005

Squamous cell carcinoma antigen-immunoglobulin M complexes as novel biomarkers for hepatocellular carcinoma.

BACKGROUND: Early detection of hepatocellular carcinoma (HCC), one of the most common and deadly tumors worldwide, still is difficult due to the lack of adequate biomarkers that show high sensitivity and specificity. The authors recently demonstrated that squamous cell carcinoma antigen (SCCA) variants were overexpressed remarkably in all surgically resected HCCs. METHODS: For the current study, the authors assessed the presence of SCCA, as a free form and complexed with immunoglobulins, in serum from patients with HCC, cirrhosis, and chronic hepatitis and from healthy control participants and compared SCCA measurement with the measurement of alpha-fetoprotein (AFP) levels. RESULTS: Circulating immune complexes (ICs) composed by SCCA and immunoglobulin M (IgM) IC (SCCA-IgM IC) were undetectable (< 120 arbitrary units [AU]/mL) in serum from a healthy control population (0 of 73 controls); however, 35 of 50 patients with HCC (70%) were reactive for SCCA-IgM IC independent of etiology (mean +/- standard deviation [SD], 2568.5 +/- 6797.3 AU/mL). No correlation was found with AFP levels, which were elevated significantly in only 21 of 50 patients with HCC (42%). By using an AFP cut-off value of 20 ng/mL, 96% of patients with HCC were positive for at least 1 marker. Among cirrhotic patients, the presence of circulating SCCA-IgM IC was displayed in 13 of 50 patients (26%), but at lower levels compared with the patients who had HCC (mean +/- SD, 147.5 +/- 348.3 AU/mL; P < 0.01; Student t test), whereas 9 of 50 patients with chronic hepatitis (18%) were reactive (mean +/- SD, 39.5 +/- 89.7 AU/mL). No significant presence of free SCCA, free anti-SCCA variants IgG or IgM, or SCCA-IgG IC was found. CONCLUSIONS: The study results indicated that SCCA-IgM ICs represent novel serologic biomarkers, which, alone or in combination with AFP, can increase the sensitivity for diagnosing HCC significantly.

Adult↗

PubMed2004

Constitutive membrane expression of proteinase 3 (PR3) and neutrophil activation by anti-PR3 antibodies.

Antineutrophil cytoplasm autoantibodies with specificity for proteinase 3 (PR3) are thought to play a major role in the pathogenesis of Wegener's granulomatosis (WG), presumably by their potential to activate neutrophils. In patients with WG, high expression of PR3 on the surface of nonprimed neutrophils is associated with an increased incidence and rate of relapse. In this study, we analyzed the functional significance of constitutive PR3 expression for neutrophil activation as induced by anti-PR3 antibody. Therefore, primed and nonprimed neutrophils were stimulated with the monoclonal anti-PR3 antibody PR3G-3. Activation was measured as actin polymerization by the phalloidin assay as an early, detectable activation event and oxidative burst by the dihydrorhodamine assay, as a late, detectable activation event. In contrast to the oxidative burst, we found that anti-PR3 antibody-induced actin polymerization could be triggered in neutrophils without priming with tumor necrosis factor alpha (TNF-alpha). In addition, a correlation was found between the level of PR3 expression on the surface of these nonprimed neutrophils and the degree of actin polymerization. However, after priming with TNF-alpha, no correlation was found between membrane expression of PR3 and the level of actin polymerization or respiratory burst as induced by anti-PR3 antibody. These data suggest that the presence of PR3 on the surface of nonprimed neutrophils has consequences for their susceptibility to the initial activation step by anti-PR3 antibodies. These data may be relevant in view of the observed relation between membrane expression of PR3 on nonprimed neutrophils of patients with WG and their susceptibility for relapses.

Actins↗

PubMed2003

Fc gamma RIIIb allele-sensitive release of alpha-defensins: anti-neutrophil cytoplasmic antibody-induced release of chemotaxins.

Antineutrophil cytoplasmic Abs (ANCA) can activate neutrophils in an FcgammaR-dependent manner, but the link between this ANCA-induced effect and mononuclear cell activation with the characteristic granuloma formation of Wegener's granulomatosis is unclear. Human alpha-defensins, small cationic antimicrobial peptides, are found in neutrophils and have chemotactic activity for T cells, dendritic cells, and monocytes. In this study, we quantitated the release of alpha-defensins (human neutrophil peptides 1-3) from human neutrophils after targeted FcgammaR cross-linking (XL). Homotypic XL of FcgammaRIIa, FcgammaRIIIb, or heterotypic XL of both receptors resulted in significant release of alpha-defensins, an effect also induced by both human polyclonal and murine monoclonal cytoplasmic staining ANCA (anti-proteinase 3). This release of alpha-defensins, as well as of other granule constituents (ANCA targets anti-proteinase 3 and myeloperoxidase and elastase), was significantly greater in donors homozygous for the NA1 allele of FcgammaRIIIb than in donors homozygous for NA2. Interestingly, the ANCA-induced release was completely inhibited by the IgG Fc-binding peptide TG19320, which blocks the IgG-Fc region from binding to FcgammaR. Based on their chemotactic properties, alpha-defensins and their release by ANCA may contribute to modulation of the acquired immune response and to granuloma formation. The greater activity of the FcgammaRIIIB-NA1 genotype may also explain the greater severity of disease and its flare-ups in patients with this allele.

Alleles↗

PubMed2002

Sequence-simplification and chimeric assembly: new models of peptide antigen modification.

Sequence-simplified variants of a 15-mer peptide antigen, identified by amino acid side chains in alternating positions were synthesized introducing glycine residues alternatively in the parent peptide sequence and used to induce antibodies in rabbit. They reacted to a significant extent with anti-parent peptide antibodies, and in addition, affinity purified antibodies against these halved forms recognized with similar affinity and specificity, the starting peptide in affinity chromatography, optical biosensor and enzyme linked immunosorbent assay (ELISA) experiments, while no cross-reactivity was detected between reduced antigens. These findings suggest that a peptide antigen can display two molecular surfaces of recognition, identified by side chains of residues in alternating positions. Each surface can even take part in antigen/antibody interaction independently, thus indicating the possibility to select and assembly sequence-simplified forms belonging to different epitopes, also deriving from different molecules, to generate new structures incorporating a two-fold antigen/antibody specificity. Two "chimeric" forms were then synthesized starting from the P15 and P13 complementary peptides, both able to bind interleukin 2. These structures, showing simultaneously trans-surfaces of recognition belonging to both parent forms, have been found to retain antigenic properties against antibodies of simplified P15 derivatives showing the same molecular surface of recognition. In addition, anti-chimeric antibodies recognized both P15 and P13 starting peptides, while no cross-antibody recognition was observed between chimeric antigens.

Amino Acid Sequence↗

PubMed2002

Novel molecular targets for systemic lupus erythematosus.

For a long time the complement cascade has been believed to be the predominant pathway to inflammation and tissue destruction in autoimmune diseases such as systemic lupus erythematosus. Recently, new evidences show that FcRs may share the primacy with complement cascade, playing an equal or greater role in the disease process. The generation of specific mouse strains deficient in individual components has clarified the different role played by complement and Fc receptors in their interaction with ICs, illustrating that complement is essential for innate immunity against microbial pathogens, requiring natural antibodies to mediate its protective effects, whereas FcyRs have evolved as the principal system for coupling antigen-antibody complexes to effector cells and initiate the inflammatory cascade. Validation of FcRs as new therapeutic targets for autoimmune diseases, in particular for Systemic Lupus Erythematosus (SLE), has been provided by a large number of studies where the biological action of soluble forms of FcyRs or of monoclonal antibodies targeting Fc receptors has been assessed. Additional support to the role of FcRs in SLE has been provided by data obtained with compounds derived from combinatorial chemistry, such as TG19320, a tetrameric tripeptide which interferes with IgG/FcgammaR interaction in vitro and prevents glomerulonephritis in vivo in a SLE susceptible mouse strain. These findings might open the way to new therapeutic approaches for disorders where the role of FcRs has been established, including not only autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis, multiple myeloma, but also acquired immunodeficiency syndrome (AIDS).

Animals↗