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C O Savage

Publications and source records attributed to C O Savage.

At least 19 recordsLinked to original sources
PubMed1992

Autoantibodies developing to myeloperoxidase and proteinase 3 in systemic vasculitis stimulate neutrophil cytotoxicity toward cultured endothelial cells.

The ability of vasculitis-associated anti-neutrophil cytoplasm antibodies (ANCA) to activate neutrophils and mediate release of radiolabel from 111Indium-labeled cultured human umbilical vein endothelial cells (HUVEC) was determined as a measure of the potential cytotoxicity of ANCA-activated neutrophils against vascular endothelium. Priming of neutrophils with low doses of phorbol 12-myristate 13-acetate (PMA) (1 ng/ml) and ionomycin (0.1 mumol/1) was required, together with pretreatment of endothelial cells with BCNU (1,3-bis-[2-chloroethyl]-1-nitrosourea; 0.26 mmol/l). Under these conditions and using a 4-hour serum-free assay system, mouse monoclonal antibodies (MAb) to the target autoantigens proteinase-3 (Pr-3) and myeloperoxidase (MPO) mediated enhanced release of 111Indium from HUVEC compared with control MAb. Human IgG Fab2 C-ANCA (recognizing Pr-3) and P-ANCA (recognizing MPO) did likewise. Preactivation of HUVEC with TNF (50 U/ml, 4 hr) enhanced the release of 111Indium from HUVEC generated by neutrophils activated with anti-Pr-3 and anti-MPO MAb. These data support the suggestion that activation of neutrophils by ANCA within the vascular lumen may contribute to endothelial cell injury.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1991

Endothelial cell lymphocyte function-associated antigen-3 and an unidentified ligand act in concert to provide costimulation to human peripheral blood CD4+ T cells.

Our previous studies have demonstrated that cultured human endothelial cells (EC) provide costimulation to PHA-activated CD4+ T cells, measured as augmentation of IL-2 synthesis, through a cell contact-department pathway. Here we show that fixed and living EC provide comparable degrees of costimulation to CD4+ T cell populations, indicating that EC costimulation does not depend upon active metabolism. EC achieve these effects in part by utilizing lymphocyte function-associated antigen-3 (LFA-3) to interact with T cell CD2 as shown by observations that EC augmentation of IL-2 is partially (50-70%) blocked by eight of eight mAb tested which recognize LFA-3; that purified phosphatidylinositol-linked LFA-3 (PI-LFA-3) can also provide costimulation to CD4+ T cells; and that there is a delay of the EC effect on CD4+ T cells which express low levels of CD2 compared to those which express high levels of CD2. However, three lines of evidence suggest that EC also utilize at least one additional ligand. First, there is incomplete replacement of the EC effect by PI-LFA-3 such that the costimulatory ability of EC combined with PI-LFA-3 is additive at all concentrations of PI-LFA-3 tested. Second, costimulation by PI-LFA-3, but not by EC, is fully inhibited by anti-CD2 or anti-LFA-3 mAb. Finally, costimulation by PI-LFA-3, but not by EC, is completely suppressed by cyclosporine A. We have not formally identified the second ligand but it does not appear to be intercellular adhesion molecule-1, vascular cell adhesion molecule-1, CD44, or B7/BB1.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Anti-neutrophil cytoplasmic antibodies and disease activity during long-term follow-up of 70 patients with systemic vasculitis.

Anti-neutrophil cytoplasmic antibodies (ANCA) have been identified as a diagnostic marker in primary systemic vasculitis, and immunofluorescence assays identify two patterns of binding: cytoplasmic (C-ANCA and perinuclear (P-ANCA). We have examined retrospectively the use of such assays in long-term monitoring of disease activity, in order to determine the relationship between presence of ANCA and relapse, and to assess their suitability as a guide to therapy. Seventy patients were studied over a period of 50 months, using clinical and laboratory criteria for the diagnosis of relapse and the internationally standardised immunofluorescence assay for detection of ANCA. In 19 patients C- or P-ANCA were detectable throughout the study period; six of these (with C-ANCA) relapsed. In 18 patients ANCA were undetectable during long-term follow-up; none of these patients relapsed. In 33 patients C- or P-ANCA were intermittently present; nine of these relapsed and all had C-ANCA detectable at the time of relapse. In six of the nine cases, relapse was accompanied or closely preceded by reappearance of C-ANCA. We conclude that continuing presence and reappearance of ANCA may identify patients who are at risk of relapse and who are most likely to benefit from long-term immunosuppressive therapy.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1991

Vascular damage in Wegener's granulomatosis and microscopic polyarteritis: presence of anti-endothelial cell antibodies and their relation to anti-neutrophil cytoplasm antibodies.

To define mechanisms of vascular injury in Wegener's granulomatosis and microscopic polyarteritis, anti-endothelial cell antibodies (AECA) were sought in serum from 168 patients, all of whom had anti-neutrophil cytoplasm antibodies (ANCA) detectable by indirect immunofluorescence. Using an ELISA with human umbilical vein endothelial cells (HUVEC), IgG AECA were demonstrated in 59% and IgM AECA in 68% of patients. Pretreatment of HUVEC with tumour necrosis factor (TNF), IL-1 or interferon-gamma (IFN-gamma) led to increased binding. Adsorption of AECA/ANCA-containing serum with HUVEC or neutrophils demonstrated that AECA and ANCA recognized different targets. von Willebrand factor (vWf) antigen levels in the patient samples were markedly elevated, with a mean of 3.10 +/- 1.89 U/ml (control population mean 1.04 +/- 0.36 U/ml), suggesting widespread endothelial cell damage. Studies using an 111In-labelled HUVEC release assay with 29 AECA-containing sera did not demonstrate complement-mediated cytotoxicity, even following activation of HUVEC with TNF. Four out of 16 AECA-containing sera tested showed antibody-dependent cellular cytotoxicity with unfractionated peripheral blood mononuclear cells. These data suggest that patients with Wegener's granulomatosis or microscopic polyarteritis can develop AECA to constitutively expressed but cytokine modulated determinants on HUVEC. These antibodies do not appear to support complement-mediated cytotoxicity, but a proportion can support antibody-dependent cellular cytotoxicity, suggesting that they may contribute to vascular injury.

Arterioles↗
PubMed1991

Immune markers in vasculitis.

Systemic vasculitides are a group of autoimmune diseases associated with intense leucocytic vascular infiltrates and the presence in the serum of autoantibodies to neutrophil enzymes. This article discusses the significance of these and other immune markers for the diagnosis and monitoring of patients with vasculitis, as well as their possible pathogenic consequences.

Autoantibodies↗
PubMed1990

Endothelial cells augment T cell interleukin 2 production by a contact-dependent mechanism involving CD2/LFA-3 interaction.

We have demonstrated that endothelial cells (EC) augment IL-2 production by PHA-stimulated PBMC or purified CD4+ T cells and that the increase is apparent both in the amount of soluble IL-2 secreted and in the level of specific mRNA detectable by Northern blot hybridization. The ability of EC to affect levels of IL-2 cannot be reproduced by soluble factors, including the cytokines IL-1, IL-6, IFN-gamma, or TNF, conditioned medium from resting EC or IL-1, IFN-gamma- or TNF-treated EC, or from resting PBMC + EC cultures. Separation of the EC and PBMC by a Transwell membrane demonstrated that cell contact was required for augmentation of IL-2 synthesis and that this effect was unlikely to be mediated by a short-lived soluble signal. The cell-cell interaction required the ligand pair CD2/LFA-3, since augmentation could be inhibited by antibodies to these structures. Antibodies to ICAM-1, LFA-1, CD4, and MHC class II were without effect. A contact-dependent pathway involving CD2/LFA-3 interactions also may be used by EC to augment IL-2 production from T cells stimulated more specifically through the TCR/CD3 complex with antibody OKT3. This pathway provides a proliferative advantage to T cells stimulated with OKT3 in the presence of EC and may also be involved in the proliferative response of resting T cells to allogeneic class II MHC-expressing EC. We propose that EC augmentation of T cell IL-2 synthesis may be critical in the ability of EC to elicit primary T cell antigen responses and may have consequences for the development of localized cell-mediated immune reactions.

Antigens, CD↗
PubMed1990

The potential roles of vascular endothelium in immune reactions.

Cell-mediated immune reactions are initiated and regulated by antigen specific CD4+ helper T cells. However, T cells cannot function independently. In order for a CD4+ T cell to recognize antigen, it must be presented in association with a class II major histocompatibility complex molecule by another cell type and, in order to lead to functional T-cell activation, the antigen presenting cell must also provide costimulatory signals. Once activated, CD4+ T cells function in vivo by secreting cytokines that elicit an inflammatory infiltrate of other cell types that serves to eliminate the source of foreign antigen. In vivo, the development of inflammation requires vascular responses as well as contributions of blood-derived leukocytes. Although several cell types in vitro can present antigen, provide costimulation, and perform actions that contribute to inflammation, vascular endothelial cells may be uniquely important immune accessory cells because they are anatomically uniquely positioned to function in vivo during cell-mediated immune reactions. In this report, we shall review recent data from our laboratories which further characterize the immune accessory functions of endothelial cells.

Antigen-Presenting Cells↗
PubMed1990

The endothelial cell as a regulator of T-cell function.

These studies have analyzed the antigen-presenting capacities of EC. EC can transcribe, translate and express MHC class II molecules in response to IFN-gamma as well as express class I molecules. The class II dimeric structure is functional, in that allospecific CTL can efficiently kill IFN-gamma-treated EC or fibroblasts, an outcome that can be blocked by antibody to non-polymorphic regions of the class II molecule. Moreover, EC can present antigen in an MHC-restricted manner to resting T cells as well as to antigen-specific cloned T-cell lines. This ability to stimulate primary as well as secondary responses has been further confirmed by experiments using purified populations of naive and memory T cells. In this regard, EC differ from fibroblasts and other non-immune cell types in that they possess costimulator activities necessary for activation of resting T cells. As the local concentration of IL-2 has been shown to be critical in determining the fate of T cells--whether they become activated or anergic--we have investigated the ability of EC to modulate T-cell IL-2 production, believing that this may underlie their ability to act as costimulatory cells. Using PHA-stimulated peripheral blood mononuclear cells or purified CD4+ T cells we have found that EC can augment IL-2 production, typically by 3- to 8-fold. This increased IL-2 production is functional as OKT3-stimulated or sub-optimally PHA-stimulated T cells proliferate more in the presence of EC than in their absence. The major pathway by which EC augment T-cell IL-2 production is cell contact-dependent and involves the CD2:LFA-3 ligand pair. However, use of blocking mAb to CD2 and LFA-3, of PI-LFA-3, and of the immunosuppressive drug CsA has allowed us to reveal the presence of a second signalling pathway. This pathway confers a certain degree of CsA resistance on T cells, but the ligands involved have not yet been identified. We do not find a role for CD28, LFA-1:ICAM-1, VLA-4:VCAM-1 or CD44 in this system. Augmentation is independent of EC metabolism or soluble factors, as fixed cells are almost as efficient as living cells. Similar mechanisms seem also to be involved in more physiological settings, such as alloresponses. Here, proliferation can be blocked by antibodies to CD2 or LFA-3, presumably by blocking of augmented IL-2 production.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Autoantibodies in primary systemic vasculitis.

Strong evidence for the presence of autoantibodies in the primary systemic vasculitides now exists, and there is a particularly marked association between ANCA and Wegener's granulomatosis and microscopic polyarteritis. The presence of ANCA serves to place these disorders in a firm autoimmune setting. Although ANCAs are of undoubted diagnostic significance, their role in etiology and pathogenesis has still to be fully explored, so further developments in this area are awaited with interest.

Autoantibodies↗
PubMed1990

Antineutrophil antibodies in vasculitis.

Antineutrophil cytoplasm antibodies appear highly specific to the primary systemic vasculitides, in particular to Wegener's granulomatosis and microscopic polyarteritis. Their occurrence in idiopathic crescentic rapidly progressive glomerulonephritis supports the view that this disorder may be regarded as a renal limited form of microscopic polyarteritis. The high sensitivity and specificity of ANCA detected using indirect immunofluorescence or solid phase techniques aids the primary diagnosis of these disorders; the measurement of ANCA may also be of value in long-term monitoring since disease relapse appears to occur only when ANCA are present, and it may therefore be inadvisable to withdraw immunosuppressive treatment until ANCA have been undetectable for extended periods of observation. However, the continued presence or reappearance of ANCA following initial induction of disease remission is not necessarily in concord with overt disease activity, although ANCA has been present in all patients in whom disease relapse has occurred. To understand further the role and relationship of ANCA to the vasculitic diseases requires elucidation of the autoantigen, and in this regard various neutrophil enzymes would appear to be likely candidates. Meanwhile, direct evidence of in vivo pathogenicity and studies of possible mechanisms of tissue injury, such as antiendothelial cell reactivity, are being sought.

Adult↗
PubMed1989

The development of anti-glomerular basement membrane nephritis in two children with Alport's syndrome after renal transplantation: characterization of the antibody target.

Two children with Alport's syndrome are described, who developed anti-glomerular basement membrane (GMB) antibody-mediated nephritis after renal transplantation. The reactivity of antibodies in their serum with collagenase-solubilized normal GBM was examined by SDS-PAGE with one- and two-dimensional immunoblotting. The specificity was compared with that of antibodies present in serum from a patient with Goodpasture's syndrome, and a mouse monoclonal antibody (MCA-P1), directed against the Goodpasture antigen. All reacted in a similar way with collagenase-solubilized GBM. Since abnormalities in the composition of the GBM are present in Alport's syndrome, it is proposed that differing antigen composition of GBM in the host compared with the donor kidney, together with transplant rejection, may have provoked the development of post-transplant anti-GBM antibodies.

Adolescent↗
PubMed1989

Variability of the antigenicity of the glomerular basement membrane in nail-patella syndrome.

The difficulty of diagnosing Alport-type nephritis, and the possibility of altered antigenicity of the glomerular basement membrane in Alport-type nephritis is discussed. Attention is focused on the monoclonal antibody MCA-Pl as a specific tool in studying the Goodpasture antigenetic determinant in renal biopsy specimens. The clinical details and the results of MCA-Pl binding studies for three patients with nail patella syndrome are presented. Two of these patients proved to have an abnormal antigenicity of the glomerular basement membrane as demonstrated by the absence of binding of MCA-Pl. This is the first time that such an abnormality has been demonstrated in patients other than those with Alport-type nephritis. The significance of these results is discussed.

Adult↗
PubMed1989

Antineutrophil cytoplasm antibodies in Kawasaki disease.

Autoantibodies against components of neutrophil cytoplasm develop during adult vasculitic diseases such as Wegener's granulomatosis and microscopic polyarteritis, and they are predominantly of the IgG class. Similar but distinct antibodies have been described in children with Kawasaki disease and both IgM and IgG class antibodies are represented. This adds another clinically distinct childhood form of vasculitis to the adult forms in which autoantibodies to neutrophil cytoplasmic antigens have been detected.

Autoantibodies↗
PubMed1989

The glomerular basement membrane defect in Alport-type hereditary nephritis: absence of cationic antigenic components.

Alport-type hereditary nephritis is a familial disorder which results in progressive renal insufficiency and sensorineural hearing loss. It is thought to result from a biochemical defect affecting basement membranes. To study this further, non-collagenous components of type IV collagen were prepared from the glomerular basement membrane (GBM) by collagenase digestion from three male patients with hereditary nephritis. The normal Goodpasture antigenicity of the 28 and 26 kD monomers and 54 and 50 kD dimers which may be isolated from the GBM was absent on one-dimensional immunoblots. Two-dimensional electrophoresis and immunoblotting studies showed absence of Goodpasture antigenicity of these molecular weight components as well as all cationic monomeric and dimeric spots. It is concluded that the expression of the Goodpasture antigen is altered in basement membranes of hereditary nephritis patients. The altered antigenicity thus acts as a marker for the underlying abnormality.

Anti-Glomerular Basement Membrane Disease↗
PubMed1989

Inherited defects of renal basement membranes.

For 15 to 20 years, electron microscopy studies have shown that some hereditary renal diseases are characterized by various abnormalities of the basement membranes. In the nail-patella syndrome, in Alport's syndrome and variants, and in benign familial hematuria, the changes involve the glomerular basement membrane (GBM). In nephronophthisis, the tubular basement membrane (TBM) is affected. These histopathologic features are not uniform. The progress afforded by biochemistry, immunology, and molecular biology allows us to compare these various lesions, to analyze their biochemical characteristics and their antigenicity, and to hypothesize as to the mechanisms involved.

Anemia↗