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Biomedical subjects

W L Gross

Publications and source records attributed to W L Gross.

At least 19 recordsLinked to original sources
PubMed1997

Incidence and disease associations of a proteinase 3-antineutrophil cytoplasmic antibody idiotype (5/7 Id) whose antiidiotype inhibits proteinase 3-antineutrophil cytoplasmic antibody antigen binding activity.

OBJECTIVE: To evaluate the potential of a monoclonal proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) antiidiotype autoantibody (5/7 anti-Id) as a candidate for specific immunotherapy in Wegener's granulomatosis (WG), and to estimate the immunodiagnostic value of the corresponding idiotype (5/7 Id). METHODS: We analyzed the incidence of 5/7 Id in patients with ANCA-associated vasculitides (WG, microscopic polyangiitis, Churg-Strauss syndrome), in disease controls (systemic lupus erythematosus patients), and in healthy donors. We then investigated the presence of 5/7 Id in relation to disease stage, clinical activity, and organ manifestations in 86 patients with WG. Finally, we investigated the ability of the 5/7 anti-Id reagent to inhibit the binding of PR3-ANCA to corresponding antigen in 19 WG patients. RESULTS: The incidence of 5/7 Id was significantly more frequent in WG patients (43 of 86; 50%). We did not find a significant correlation between the prevalence of idiotype expression and disease activity or organ manifestations. Further, we demonstrated in vitro suppression of PR3-ANCA antigen binding activity by 5/7 anti-Id in 11 of 19 WG patients who were positive for 5/7 Id. CONCLUSION: This study shows that 5/7 Id is a common idiotype with a significantly increased incidence in WG and that 5/7 anti-Id inhibits PR3-ANCA antigen binding activity. Based on these observations, we conclude that 5/7 anti-Id is a promising tool for the development of a specific immunotherapy for WG.

Adolescent↗
PubMed1996

Neutrophil activation by anti-proteinase 3 antibodies in Wegener's granulomatosis: role of exogenous arachidonic acid and leukotriene B4 generation.

Among the anti-neutrophil cytoplasmic antibodies (ANCA), those targeting proteinase 3 (PR3) have a high specificity for Wegener's granulomatosis (WG). It is known that a preceding priming of neutrophils with cytokines is a prerequisite for membrane surface expression of PR3, which is then accessible to autoantibody binding. Employing a monoclonal antibody directed against human PR3 and ANCA-positive serum from WG patients with specificity for PR3, we now investigated the role of free arachidonic acid (AA) in autoantibody-related human neutrophil activation. Priming of neutrophils with tumor necrosis factor (TNF-alpha) for 15 min or exposure to anti-PR3 antibodies or incubation with free AA (10 microM) as sole events did not provoke superoxide generation, elastase secretion or generation of 5-lipoxygenase products of AA. Similarly, the combination of TNF-alpha-priming and AA incubation was ineffective. When TNF-alpha-primed neutrophils were stimulated by anti-PR3 antibodies, superoxide and elastase secretion was provoked in the absence of lipid mediator generation. However, when free AA was additionally provided, a strong activation of the 5-lipoxygenase pathway was demasked, with the appearance of excessive quantities of leukotriene (LT)B4, LTA4, and 5-hydroxyeicosatetraenoic acid. Moreover, superoxide and elastase secretion were markedly amplified, and studies with 5-lipoxygenase inhibitors and a LTB4-antagonist demonstrated this was due to an LTB4-related autocrine loop of cell activation. In contrast, the increased synthesis of platelet-activating factor in response to TNF-alpha-priming and anti-PR3 stimulation did not contribute to the amplification loop of neutrophil activation under the given conditions. We conclude that anti-PR3 antibodies are potent inductors of the 5-lipoxygenase pathway in primed human neutrophils, and extracellular free AA, as provided at an inflammatory focus, synergizes with the autoantibodies to evoke full-blown lipid mediator generation, granule secretion and respiratory burst. Such events may be enrolled in the pathogenesis of focal necrotizing vascular injury in Wegener's granulomatosis.

Arachidonate 5-Lipoxygenase↗
PubMed1996

Development and standardization of solid phase assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). A report on the second phase of an international cooperative study on the standardization of ANCA assays.

Anti-neutrophil cytoplasmic antibodies (ANCA) are diagnostic markers for systemic vasculitis. They are classically detected by an indirect immunofluorescence test using normal donor neutrophils as substrate. This assay lacks antigenic specificity and is not quantitative. The 'EC/BCR Project for ANCA Assay Standardization' is an international collaboration study with the aim to develop and standardize solid phase assays for ANCA detection. In this part of the study the isolation and characterization of proteinase-3 and myeloperoxidase, the two main target molecules for ANCA, and the development and standardization of ELISAs with these antigens are described. Six laboratories successfully isolated purified proteinase-3 preparations that could be used. Three of these preparations, together with one myeloperoxidase preparation, were subsequently used for ANCA testing by ELISA. The ELISA technique was standardized in two rounds of testing in the 14 participating laboratories. The coefficient of variation of these new assays decreased from values of approx. 50% in the first round to approx. 20% in the second round. We conclude that purified proteinase-3 and myeloperoxidase can be used in standardized ELISAs for ANCA detection. Whether such procedures offer advantages over the IIF test will be determined in a prospective clinical study.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1996

Nitric oxide inhibits creatine kinase and regulates rat heart contractile reserve.

Cardiac myocytes express both constitutive and cytokine-inducible nitric oxide syntheses (NOS). NO and its congeners have been implicated in the regulation of cardiac contractile function. To determine whether NO could affect myocardial energetics, 31P NMR spectroscopy was used to evaluate high-energy phosphate metabolism in isolated rat hearts perfused with the NO donor S-nitrosoacetylcysteine (SNAC). All hearts were exposed to an initial high Ca2+ (3.5 mM) challenge followed by a recovery period, and then, either in the presence or absence of SNAC, to a second high Ca2+ challenge. This protocol allowed us to monitor simultaneously the effect of SNAC infusion on both contractile reserve (i.e., baseline versus high workload contractile function) and high-energy phosphate metabolism. The initial high Ca2+ challenge caused the rate-pressure product to increase by 74 +/- 5% in all hearts. As expected, ATP was maintained as phosphocreatine (PCr) content briefly dropped and then returned to baseline during the subsequent recovery period. Control hearts responded similarLy to the second high Ca2+ challenge, but SNAC-treated hearts did not demonstrate the expected increase in rate-pressure product. In these hearts, ATP declined significantly during the second high Ca2+ challenge, whereas phosphocreatine did not differ from controls, suggesting that phosphoryl transfer by creatine kinase (CK) was inhibited. CK activity, measured biochemically, was decreased by 61 +/- 13% in SNAC-treated hearts compared to controls. Purified CK in solution was also inhibited by SNAC, and reversal could be accomplished with DTT, a sulfhydryl reducing agent. Thus, NO can regulate contractile reserve, possibly by reversible nitrosothiol modification of CK.

Acetylcysteine↗
PubMed1996

Expression of the human autoantigen of Wegener's granulomatosis (PR3) in a baculovirus expression system.

Proteinase 3 (PR3) is a multifunctional serine protease found in myeloperoxidase-positive granula of PMN. It is also the main target antigen for antineutrophil cytoplasmic antibodies (ANCA) found in Wegener's granulomatosis (WG). There is ample evidence that these autoantibodies play an active role in the pathogenesis of this disease. We have established the expression of the autoantigen (PR3) in a baculovirus expression system using insect cells. Recombinant PR3 was identified by IIF, direct ELISA using 3 different MoAbs and by catching ELISA using a MoAb and a rat polyclonal Ab or cANCA-positive WG patient sera. As purification of human PR3 from blood-derived PMNs has been shown to be difficult and very inefficient, insect cell-derived recombinant PR3 offers new possibilities for obtaining sufficient amounts of this protein to facilitate further biochemical characterizations.

Animals↗
PubMed1996

Monoclonal antibody WGM1 directed against proteinase 3: an immunohistochemical marker for naphthol ASD chloroacetate.

Enzyme histochemistry for naphthol ASD chloroacetate (NASDCA, 'Leder's stain') is used to identify the granulocyte lineage ranging from promyelocytes to mature neutrophils and is an additional tool for the characterization of leukemias. We demonstrated for the first time that NASDCA activity can be detected by routine immunohistochemistry and immunocytochemistry using the monoclonal antibody WGM1 directed against proteinase 3 (PR3; synonyms: Wegener's autoantigen, myeloblastin). Immunohisto- and immunocytochemical staining with WGM1 against PR3 and enzyme histochemistry for NASDCA produced identical staining patterns in normal myelomonocytic cells and cells of myeloid leukemia. This was additionally proven by double immunostainings. We have also shown that PR3 is one of the specific proteinases responsible for hydrolysis of NASDCA.

Adolescent↗
PubMed1996

Therapy for the maintenance of remission in sixty-five patients with generalized Wegener's granulomatosis. Methotrexate versus trimethoprim/sulfamethoxazole.

OBJECTIVE: To compare the efficacy of low-dose intravenous (IV) methotrexate (MTX; 0.3 mg/kg once weekly), both with and without concomitant prednisone, versus daily oral trimethoprim/sulfamethoxazole (T/S; 160 mg of trimethoprim + 800 mg of sulfamethoxazole twice a day), with and without prednisone, in maintaining remission in patients with generalized Wegener's granulomatosis (WG). METHODS: In this study, 65 patients with generalized WG whose disease had entered remission with cyclophosphamide (CYC) and prednisone therapy were started on one of the following remission-maintenance regimens: MTX alone (group A; n = 22), T/S alone (group B; n = 24), MTX plus concomitant prednisone (group C; n = 11), and T/S plus concomitant prednisone (group D; n = 8). Clinical, radiographic, and seroimmunologic data were evaluated to assess the efficacy of the 4 regimens and to seek possible predictive factors concerning outcome in each group. RESULTS: Partial or complete remission was maintained in 86% of the patients in group A, but in only 58% of those in group B (P < 0.05). In group C, 91% of patients remained in remission, which is in sharp contrast to group D, in which all patients experienced a relapse after a median of 14.5 months (P < 0.005). Side effects occurred twice as often with MTX (n = 12) as with T/S (n = 6) treatment and could usually be resolved by supplemental folinic acid. Two patients taking MTX and 3 patients taking T/S were withdrawn from the study medication because of side effects. In none of the patients were the adverse effects life threatening. No statistically significant factors predictive of poor outcome emerged in any group. CONCLUSION: Low-dose MTX was found to be superior to T/S for the safe and effective maintenance of remission in patients with generalized WG. The use of concomitant prednisone was not associated with a worse outcome with MTX treatment. Since T/S, especially with concomitant prednisone, seemed to increase the chance of relapse, neither T/S alone nor T/S plus prednisone can be recommended for the maintenance of remission in patients with generalized WG.

Adolescent↗
PubMed1996

Long-term tolerability of methotrexate at doses exceeding 15 mg per week in rheumatoid arthritis.

The objective of this study was to examine longitudinally the tolerability of methotrexate (MTX) treatment at doses exceeding 15 mg/week in an open-label, prospective study. One hundred and eighty-five patients with rheumatoid arthritis were randomized to receive 15 mg or 25 mg MTX per week initially, and were followed over 30 months. Subsequent dose adjustments according to efficacy and tolerability resulted in levelling off of the mean dose at 18 mg/week, and the original treatment groups were combined for a longitudinal study comparing toxic events during months 1-12 and months 13-30. Withdrawals due to side-effects amounted to 17% during months 1-12 and 4% during months 13-30; dose reductions due to side-effects were 9% and 7%, respectively. The annual incidence of gastrointestinal side-effects increased from 26% to 39% (P = 0.05), that of liver enzyme elevation dropped from 43% to 10% (P < 0.001) and haemocytopenia remained stable at 5% and 7%. MTX pneumonitis was only observed during the first year, while airway complaints without evidence of parenchymal lung involvement increased to 10% beyond the first year. Fifty-six patients experienced 65 major infectious episodes over the 30-month period, with the respiratory tract being the most frequent site. This study showed that MTX treatment at doses exceeding 15 mg/week is tolerated over extended period of time. Major toxicity and withdrawals due to side-effects occurred predominantly during the first year of treatment and thus showed a decreasing trend over time, while minor toxic events continued throughout the study with a progressive rate of mucous membrane toxicity. MTX-treated RA appears to be a risk situation for major infection.

Aged↗
PubMed1996

Sustained cough in methotrexate therapy for rheumatoid arthritis.

Sustained cough is a frequent complaint in methotrexate (MTX) treatment for rheumatoid arthritis and can be a symptom of incipient MTX-induced pneumonitis. This study was performed to characterize MTX-associated cough clinically and to clarify by which means this condition can be distinguished from incipient MTX pneumonitis. Three patients with MTX-induced pneumonitis and 10 patients with sustained cough unassociated with pneumonitis were examined clinically, by pulmonary function testing, and bronchoalveolar lavage (BAL). In MTX pneumonitis, cough was associated with progressive dyspnoea, constitutional symptoms, impaired pulmonary function, and interstitial infiltration of variable degree by chest X-ray. BAL cytology invariably showed lymphocytic alveolitis while transbronchial biopsy revealed active interstitial inflammation in only one patient. Ten patients had sustained, nonprogressive cough in the absence of constitutional symptoms, progressive dyspnoea and impaired pulmonary function. Neither X-ray nor BAL nor transbronchial biopsy revealed any evidence of interstitial lung disease. In the majority of these patients, cough abated with symptomatic treatment with or without temporary discontinuation of MTX. It is concluded that MTX-associated cough can be a reflection of isolated airway disease. Clinically, absence of constitutional symptoms, impaired pulmonary function, and interstitial infiltration on X-ray distinguished this condition from incipient MTX pneumonitis. Cough without pulmonary parenchymal involvement appears to result from an irritant effect of MTX on the airways.

Aged↗
PubMed1996

Clinical relevance of elevated serum thrombomodulin and soluble E-selectin in patients with Wegener's granulomatosis and other systemic vasculitides.

PURPOSE: Vascular injury plays an important pathophysiological role in vasculitis. Soluble serum thrombomodulin (sTM), a promising marker of endothelial cell injury, is released into the circulating blood following cell damage and was therefore investigated as a parameter of disease activity in patients with Wegener's granulomatosis (WG) and various other vasculitides. PATIENTS AND METHODS: One hundred and ninety-seven sera of 102 patients with histologically proven WG of different disease activity and 41 sera of patients with other vasculitides at their active stage were investigated (12 Takayasu arteritis [TA], 7 giant cell arteritis [GCA], 10 polyarteritis nodosa [PAN], 12 Behcet's disease [BD]). The sera were examined for the levels of sTM and sE-selectin (CD62E) by enzyme-linked immunosorbent assay (ELISA) and for the presence of classical anti-neutrophil cytoplasmic antibodies (cANCA) by indirect immunofluorescence (IIF). The disease activity was evaluated according to the clinical symptoms and organ involvement. RESULTS: A significant increase of sTM levels compared with control values (26 +/- 2 ng/ml) was found in active WG, TA, GCA, PAN, and BD: limited active WG: 63 +/- ng/ml; generalized active WG: 119 +/- 15 ng/ml; limited WG, partial remission: 60 +/- 5 ng/ml; generalized WG, partial remission: 75 +/- 7 ng/ml; active TA: 36 +/-; active GCA: 36 +/- 4 ng/ml, active PAN: 33 +/- 2 ng/ml, active BD: 40 +/- 4 ng/ml. Limited and generalized WG in complete remission did not have elevated levels of sTM. sTM values closely reflected relapses and therapy-induced remissions of WG. Elevated cANCA titers were correlated as well with the disease activity in WG but more weakly than sTM levels. In contrast, sE-selectin values were not significantly correlated with the disease activity and the course of disease. CONCLUSIONS: sTM is a promising serological marker of disease activity and progression in active limited and generalized WG and other vasculitides reflecting the degree of endothelial cell damage. sTM might prove to be a clinically useful marker for therapeutic considerations.

Adult↗
PubMed1996

Anti-neutrophil cytoplasmic antibodies (ANCA) directed against bactericidal/permeability increasing protein (BPI): a new seromarker for inflammatory bowel disease and associated disorders.

It was our purpose to determine the immunodiagnostic value of ANCA directed against BPI in diseases known to be associated with ANCA, such as ANCA-associated vasculitides, inflammatory bowel disease (IBD) and the associated condition primary sclerosing cholangitis. The immunoreactivity of recombinant PBI (rBPI) was established in order to develop an ELISA specific for rBPI. By means of this assay, BPI-ANCA were assessed in sera of 178 patients with IBD or the associated disorder primary sclerosing cholangitis, 112 patients with ANCA-associated vasculitides, and in sera of 182 disease and 140 health controls. BPI-ANCA were found to be closely associated with IBD and primary sclerosing cholangitis (34% and 44% of ANCA-positive sera, respectively). By contrast, BPI-ANCA positivity was low (<10%) in the double-negative sera of patients with ANCA-associated vasculitides and in disease and health controls. BPI-ANCA appear to constitute an important marker for IBD and primary sclerosing cholangitis, but not for the ANCA-associated vasculitides.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1996

Transforming growth factor-beta (TGF-beta) expression and interaction with proteinase 3 (PR3) in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis.

TGF-beta is a multifunctional cytokine modulating the onset and course of autoimmune diseases as shown in experimental models. The aim of this study was to investigate TGF-beta expression in ANCA-associated vasculitis (AAV), and the possible interactions of this cytokine with lysosomal enzymes identified as ANCA autoantigens (e.g. PR3). This included TGF-beta effects on the translocation of the lysosomal enzymes to the cell surface of polymorphonuclear neutrophils (PMN), and the presumed activation of non-bioactive, latent TGF-beta by these enzymes. Patients with various types of systemic vasculitis (SV) were studied, including three different types of AAV (Wegener's granulomatosis (WG), Churg-Strauss syndrome (CSS) and microscopic polyangiitis (MPA)). Regardless of the type of assay applied, the TGF-beta 1 isoform was found to be over-expressed in SV, including AAV, and to correlate with disease activity as shown for WG. Mean TGF-beta 1 plasma levels in AAV patients ranged from 8.9 ng/ml (WG) to 13.3 ng/ml (CSS) (control 4.2 ng/ml; P < 0.01), while TGF-beta 2 levels were not elevated. Flow cytometry analysis showed TGF-beta 1 to be a potent translocation factor for PR3 comparable to other neutrophil-activating factors such as IL-8. PR3 membrane expression on primed PMN increased by up to 51% after incubation with TGF-beta 1. PR3 itself was revealed as a potent activator of latent TGF-beta, thus mediating bioeffects of this cytokine. These findings, together with other features of TGF-beta such as induction of angiogenesis and its strong chemotactic capacity, indicate that TGF-beta might serve as a proinflammatory factor in SV, especially in AAV.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1996

Response to trimethoprim/sulfamethoxazole in Wegener's granulomatosis depends on the phase of disease.

We prospectively studied trimethoprim/sulfamethoxazole (T/S) in inducing remission in 'initial phase' Wegener's granulomatosis (WG), and in sustaining remission in generalized WG, in 72 patients in various disease stages. Nineteen patients with initial phase WG received T/S (2 x 960 mg/day). Another 24 patients with generalized WG received the same dose of T/S (group A) and were compared with 21 patients receiving no further treatment after standard therapy (group B). Eight patients were given T/S plus low-dose prednisone (group C). Eleven of 19 patients (58%) with initial phase WG achieved complete or partial remission lasting a median 43 months (range 6-88 months). Of the remaining eight (42%), five showed local disease progression, and three developed generalized WG. In group A (T/S alone, generalized WG), 10/24 (42%) suffered a relapse after a median 13 months (range 4-58 months). In group B (generalized WG, no further treatment) 29% of patients relapsed after a median 22.5 months (range 18-26 months). All eight patients treated with T/S plus low-dose prednisone (group C) suffered serious relapse after 2-24 months. T/S induced long-term remission in > 50% of patients with initial phase WG; however, neither T/S alone nor T/S plus low-dose prednisone sustained remission in generalized WG.

Adult↗
PubMed1996

Anti-neutrophil cytoplasmic antibodies in generalized autoimmune diseases.

Anti-neutrophil cytoplasmic antibodies (ANCA) are a system of autoantibodies which are strongly associated with the primary systemic vasculitides (PSV). cANCA, as detected by indirect immunofluorescence, are mostly reactive to proteinase 3 (PR3) and bear high sensitivity and specificity for Wegener's granulomatosis. pANCA have varied subspecificities and clinical associations. The most important subspecificity of pANCA is anti-myeloperoxidase (MPO), which is strongly associated with microscopic polyaniitis and pauci-immune crescentic glomerulonephritis. pANCA also occur at low to moderate frequency in other PSV, collagen vascular disease, inflammatory bowel disease and autoimmune liver disease. In systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), pANCA of varied subspecificity have been found, including anti-MPO at low rate and low titer, while cANCA and anti-PR3 were generally absent. Consequently, anti-PR3 (PR3-ANCA) and anti-MPO (MPO-ANCA) at moderate and high titer are distinguishing features of the PSV and, in an appropriate clinical setting, argue strongly against the presence of SLE or RA. Since no significant clinical association has been found for other pANCA subspecificities, cANCA, PR3-ANCA and MPO-ANCA remain the critical elements of ANCA testing in the clinical diagnosis of generalized autoimmune diseases.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1996

Pulmonary sarcoidosis coexisting with systemic lupus erythematosus.

A 23 year old female presented with fatigue, Raynaud's syndrome, symmetric polyarthritis, lymphocytopenia, hypocomplementemia, IgG elevation, and antinuclear antibodies with anti-U1RNP specificity. A diagnosis of systemic lupus erythematosus (SLE) was made. Disseminated micronodular infiltration in the chest X-ray, a pattern of lymphocytic alveolitis by bronchoalveolar lavage, histologic demonstration of non-caseating epitheloid microgranulomas, and rapid reversal of lung disease upon low-dose methylprednisolone treatment led to a diagnosis of concomitant sarcoidosis. Clues to the diagnosis of sarcoidosis coexisting with SLE are discussed.

Adult↗