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Peter Lamprecht

Publications and source records attributed to Peter Lamprecht.

At least 19 recordsLinked to original sources
PubMed2006

[Rheumatology -- Part 3. Research news concerning epidemiology, diagnosis, and therapy of primary systemic vasculitides].

Antineutrophil cytoplasmic autoantibody-(ANCA-)associated vasculitides, immune complex-mediated vasculitides and granulomatous arteritides of unknown etiology belong to the group of primary systemic vasculitides. Numerous in vitro and in vivo studies have underscored the role of ANCA in the pathogenesis of ANCA-associated vasculitides (Wegener's granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome) in the meantime. Whereas the pathogenicity of myeloperoxidase (MPO) ANCA has been supported by data from various animal models in the past, the in vivo pathogenicity of proteinase 3 (PR3) ANCA has been demonstrated in an animal model only recently. Other studies showed an altered T-cell response in Wegener's granulomatosis. Hepatitis C virus-(HCV-)associated cryoglobulinemic vasculitis is mediated by immune complexes. Recent data suggest that the HCV core particles concentrated in the cryoprecipitate apparently play a role in the interaction of cryoglobulin and endothelial cells and neutrophil granulocytes. Data from the European Vasculitis Study Group (EUVAS) demonstrate the efficacy of azathioprine in maintaining remission in ANCA-associated vasculitides on the basis of large patient numbers. Biologicals play an increasing role in the treatment of refractory vasculitis.

Adrenal Cortex Hormones↗
PubMed2006

[Rheumatology-part 2. Research news concerning pathogenesis, epidemiology, diagnosis, and therapy of connective tissue disease].

Due to the partial elucidation of the immunopathogenesis of chronic inflammatory diseases during the last years, clinical rheumatology has made a rapid development, which by the consequent use of immunomodulatory therapies including recombinant proteins (biologicals) led to a significantly ameliorated prognosis of these diseases. On this basis, new research projects are continuously performed in the fields of pathogenesis, new drug development, outcome and therapy studies. New developments of imaging techniques and serologic testing facilitate a better classification and definition of disease activity and remission criteria. The current state of research in the field of collagen vascular diseases with its clinical consequences is reviewed in this article on the basis of the most recent data available.

Biological Products↗
PubMed2006

Wegener autoantigen induces maturation of dendritic cells and licenses them for Th1 priming via the protease-activated receptor-2 pathway.

Autoantibodies to proteinase 3 (PR3) are involved in the pathogenesis of autoimmune-mediated vasculitis in Wegener granulomatosis (WG). To address the question how the autoantigen PR3 becomes a target of adaptive immunity, we investigated the effect of PR3 on immature dendritic cells (iDCs) in patients with WG, healthy blood donors, and patients with Crohn disease (CD), another granulomatous disease. PR3 induces phenotypic and functional maturation of a fraction of blood monocyte-derived iDCs. PR3-treated DCs express high levels of CD83, a DC-restricted marker of maturation, CD80 and CD86, and HLA-DR. Furthermore, the DCs become fully competent antigen-presenting cells and can induce stimulation of PR3-specific CD4(+) T cells, which produce IFN-gamma. PR3-maturated DCs derived from WG patients induce a higher IFN-gamma response of PR3-specific CD4(+) T cells compared with patients with CD and healthy controls. The maturation of DCs mediated through PR3 was inhibited by a serine protease inhibitor, by antibodies directed against the protease-activated receptor-2 (PAR-2), and by inhibition of phospholipase C, suggesting that the interactions of PR3 with PAR-2 are involved in the induction of DC maturation. Wegener autoantigen interacts with a "gateway" receptor (PAR-2) on iDCs in vitro triggering their maturation and licenses them for a T helper 1 (Th1)-type response potentially favoring granuloma formation in WG.

Adult↗
PubMed2006

Advances in the therapy of Wegener's granulomatosis.

PURPOSE OF REVIEW: In the past, recommendations for the treatment of Wegener's granulomatosis were primarily based on findings reported from open-label clinical trials. Results from several randomized controlled trials in patients with Wegener's granulomatosis and other antineutrophil cytoplasm antibody-associated vasculitides have recently been reported that have a great impact on patient care. RECENT FINDINGS: In view of the considerable toxicity of cyclophosphamide, strategies to limit exposure to it have recently been evaluated. The replacement of cyclophosphamide by azathioprine after the successful induction of remission has been demonstrated not to increase the rate of relapse compared with continued cyclophosphamide. In patients with early antineutrophil cytoplasm antibody-associated vasculitides without critical organ manifestations low-dose methotrexate can replace cyclophosphamide for induction treatment with similar remission rates. As the early discontinuation of immunosuppressive treatment is associated with unacceptably high relapse rates, however, treatment for the maintenance of remission is mandatory. Besides azathioprine, leflunomide and methotrexate were efficacious in preventing relapses in Wegener's granulomatosis. Data on anti-cytokine therapy in Wegener's granulomatosis are controversial, possibly related to differences in study design. Open-label clinical studies suggest a beneficial effect of infliximab in addition to standard therapy in refractory Wegener's granulomatosis. In contrast, a recent randomized controlled trial showed that etanercept in addition to standard therapy, with the subsequent tapering of standard medications, is not effective for the maintenance of remission. SUMMARY: Despite recent progress, the prevention of relapses and treatment of refractory cases remain the greatest challenges in the treatment of Wegener's granulomatosis.

Antibodies, Monoclonal↗
PubMed2005

TNF-alpha inhibitors in systemic vasculitides and connective tissue diseases.

The introduction of TNF-alpha inhibitors in the treatment of rheumatoid arthritis and several other diseases meant a major progress in the management and to the understanding of these chronic inflammatory diseases. In this article, the evidence of the role of TNF-alpha and for TNF-alpha inhibitors in systemic vasculitides and connective tissue diseases is reviewed. TNF-alpha is expressed in inflammatory lesions. TNF-alpha acts as a proinflammatory cytokine in most disease processes analyzed so far, but it might have anti-inflammatory properties under certain conditions as well, e.g. with respect to B-cell regulation in systemic lupus erythematosus. It is not clear to what extent such aspects will be important in the treatment of connective tissue diseases and systemic vasculitides with TNF-alpha inhibitors. So far, most case reports and case series have suggested favourable results with TNF-alpha inhibitor therapy in systemic lupus erythematosus, dermato- and polymyositis, giant cell arteritis, Churg-Strauss syndrome, Wegener's granulomatosis and microscopic polyangiitis. Results of randomized, placebo-controlled trials are awaited for several connective tissue diseases and systemic vasculitides. One randomized, placebo-controlled trial has found no efficacy of infliximab treatment in primary Sjögren's syndrome recently.

Connective Tissue Diseases↗
PubMed2005

Wegener's granulomatosis: a view from the granulomatous side of the disease.

Although the airway granulomata in Wegener's granulomatosis were stressed initially by Friedrich Wegener himself, in the last few decades systemic lesions mainly caused by acute vasculitis have received the most attention. However, recently, the implication of granulomatous manifestations in WG has raised much interest. The present data suggest that an aberrant Th1-type response might play a role in the initiation of WG, clinico-pathologically characterized by granulomatous inflammation rather than vasculitis. Disease progression to generalized WG with the predominance of vasculitic manifestations is associated with a "switch" or further complexity of the collective T cell response with the appearance of another subset of Th2-type cells and a less prominent Th1-type cytokine production in the granulomatous lesions of the upper respiratory tract. However, the clinical significance of the granulomatous inflammation is not yet completely understood. Further research will also have to focus on the role of the granulomata during relapsing disease. We review present knowledge of granulomatous inflammation in WG. Morphologic aspects, the scale of cytokine alterations as well as the variety of clinical manifestations are discussed.

Cytokines↗
PubMed2004

[New aspects in ANCA-associated vasculitides].

Wegener's granulomatosis (WG), microscopic polyangiitis, and Churg-Strauss syndrome belong to the group of ANCA-associated vasculitides. Numerous in vitro studies underscored the role of antineutrophil cytoplasmic antibodies (ANCA) in the pathogenesis of vasculitis. More recently, a mouse model provided in vivo evidence of the pathogenic role of ANCA by inducing a vasculitis after the transfer of splenocytes or MPO-ANCA. The target antigens of ANCA, myeloperoxidase (MPO) and proteinase 3 (PR3), are translocated onto the cell surface after priming of neutrophil granulocytes with cytokines. ANCA bind to target antigens and activate neutrophil granulocytes resulting in premature degranulation and endothelial cell damage (ANCA-cytokine sequence theory). Both the F(ab')2 end and the FcgammaR(eceptor) end of the ANCA are involved in activating neutrophil granulocytes. This mode of activation might account for differences to normal neutrophil activation via the FcgammaR. In addition, an expansion of T-cells lacking the co-stimulatory molecule CD28 is seen in WG suggesting an altered cellular immune response. Data from European multicenter studies demonstrated, among other things, that azathioprine can be used for the maintenance of remission after successful induction of remission with cyclophosphamide in ANCA-associated vasculitides.

Animals↗
PubMed2004

Wegener's granulomatosis.

Wegener's granulomatosis is an organ- and/or life-threatening autoimmune disease of as yet unknown etiology. The classic clinical triad consists of necrotizing granulomatous inflammation of the upper and/or lower respiratory tract, necrotizing glomerulonephritis, and an autoimmune necrotizing systemic vasculitis affecting predominantly small vessels. The detection of antineutrophil cytoplasmic antibodies directed against proteinase 3 (PR3-ANCA) is highly specific for Wegener's granulomatosis. ANCA positivity is found only in about 50% of the patients with localized Wegener's granulomatosis (which is restricted to the respiratory tract and affects < or = 5% of the patients), whereas PR3-ANCA positivity is seen in 95% of the patients with generalized Wegener's granulomatosis. Studies showing an expansion of circulating tumor necrosis factor-(TNF-)alpha-producing Th1-type CD4(+)CD28(-) T-cell effector memory T-cells and their presence as Th1-type cytokine profile- driving cell population within granulomatous lesions provide the rationale for using TNF-alpha-blocking agents in Wegener's granulomatosis refractory to standard induction therapy with cyclophosphamide and corticosteroids ("Fauci's scheme"). Vasculitis is an independent risk factor for diffuse endothelial dysfunction and may be a consequence of TNF-alpha action on endothelial cells. Recently, another study has shown intima-media thickening of the wall of the common carotid artery and bulb, as well as a significantly increased incidence of stroke, myocardial infarction and occlusive artery disease in Wegener's granulomatosis. This study suggests that systemic inflammation and vasculitis contribute to accelerated arteriosclerosis in Wegener's granulomatosis.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2004

Frequency of proteinase 3 (PR3)-specific autoreactive T cells determined by cytokine flow cytometry in Wegener's granulomatosis.

OBJECTIVE: Previous studies have shown proliferation to Wegener's autoantigen, proteinase 3 (PR3). We tested immunogenicity of PR3-derived peptides and determined frequencies of PR3-specific T cells using cytokine flow cytometry in Wegener's granulomatois (WG). METHODS: Peripheral blood T-cell responses were measured after stimulation with previously described PR3-derived peptides. PBMC were stimulated with PR3-derived peptides or control stimuli for up to 10 days. Cells were stained with antibodies against CD4 or CD8, CD69 and intracellular TNF-alpha and analyzed by flow cytometry. PR3-specific T cells were counted as the percentage of CD69(+)TNF-alpha(+)double positive T cells after stimulation. RESULTS: Frequencies of PR3-specific peripheral blood T cells after short-term stimulation (<or=0.4%) were lower compared to frequencies of PR3-specific CD4(+)T cells (0.64+/-0.09%, mean+/-SEM) and PR3-specific CD8(+)T cells (0.65+/-0.18%) after 10 days of stimulation in WG. There were no differences of the frequency of PR3-specific T cells between WG and healthy controls after stimulation with other peptides. The frequency of PR3-specific CD8(+)T cells stimulated with a preferentially HLA-A*0201 binding PR3-peptide sequence was higher compared to the frequency of T cells stimulated with a HLA-B*0702 binding PR3-peptide in one WG patient whose HLA type was known (A2B7). CONCLUSION: Low frequencies of TNF-alpha(+)PR3-specific T cells can be detected in individual WG patients and controls using cytokine flow cytometry. The pattern and time course of cytokine production in response to PR3 peptides needs to be further elucidated. Additional factors such as the influence of proinflammatory or regulatory T cells might be important for the induction of autoimmunity in WG.

Amino Acid Sequence↗
PubMed2003

Alterations in the phenotype of CMV-specific and total CD8+ T-cell populations in Wegener's granulomatosis.

Wegener's granulomatosis (WG) is an autoimmune disease of as yet unknown etiology. To date it has remained obscure what causes WG or determines disease progression. Case reports suggest that viral infections such as cytomegalovirus (CMV) reactivation may contribute to disease flares. In this study we found a skewing of the phenotype of CMV-specific CD8+tet(ramer)+ T-cells in WG. A marked proportion of these cells displayed a late differentiated "effector memory" T-cell phenotype with decreased expression of CD28 and CD62L, and heterogeneous CD27 expression, features which were also seen in CD8+tet- T-cells in WG, but not in controls. Our results might reflect profound generalized changes in the CD8+ T-cell compartment also affecting virus-specific T-cell responses in WG.

ADP-ribosyl Cyclase↗
PubMed2003

Differences in CCR5 expression on peripheral blood CD4+CD28- T-cells and in granulomatous lesions between localized and generalized Wegener's granulomatosis.

Wegener's granulomatosis (WG) is an autoimmune disease characterized by granulomatous lesions and a necrotizing vasculitis. Th1-type-cells lacking CD28 are expanded independent of age and immunosuppressive therapy in WG. To address their migratory properties of CD4(+)CD28(-) T-cells we studied the expression of the inducible inflammatory Th1-type chemokine receptor CCR5 in localized WG and generalized WG. Expansion of CD4(+)CD28(-) T-cells was more prominent in generalized WG compared to localized WG. In localized WG a larger fraction of CD4(+)CD28(-) T-cells displayed CCR5 expression compared to generalized WG. CCR5 expression was also higher in granulomatous lesions in localized WG. Higher levels of CCR5 expression on CD4(+)CD28(-) T-cells in localized WG may favor stronger CCR5-mediated recruitment of this T-cell subset into granulomatous lesions in localized WG. Expansion of Th-1-type CD4(+)CD28(-)CCR5(+) effector memory T-cells might contribute to disease progression and autoreactivity, either directly, by maintaining the inflammatory response, or as a result of bystander activation.

CD28 Antigens↗
PubMed2002

Heterogeneity of CD4 and CD8+ memory T cells in localized and generalized Wegener's granulomatosis.

Memory T cells display phenotypic heterogeneity. Surface antigens previously regarded as exclusive markers of naive T cells, such as L-selectin (CD62L), can also be detected on some memory T cells. Moreover, a fraction of CD45RO+ (positive for the short human isoform of CD45) memory T cells reverts to the CD45RA+ (positive for the long human isoform of CD45) phenotype. We analyzed patients with biopsy-proven localized Wegener's granulomatosis (WG) (n = 5), generalized WG (n = 16) and age- and sex-matched healthy controls (n = 13) to further characterize memory T cells in WG. The cell-surface expression of CD45RO, CD45RA, CD62L, CCR3, CCR5 and CXCR3 was determined on blood-derived T cells by four-color flow cytometric analysis. The fractions of CCR5+ and CCR3+ cells within the CD4+CD45RO+ and CD8+CD45RO+ memory T cell populations were significantly expanded in localized and generalized WG. The mean percentage of Th1-type CCR5 expression was higher in localized WG. Upregulated CCR5 and CCR3 expression could also be detected on a fraction of CD45RA+ T cells. CD62L expression was seen on approximately half of the memory T cell populations expressing chemokine receptors. This study demonstrates for the first time that expression of the inducible inflammatory chemokine receptors CCR5 and CCR3 on CD45RO+ memory T cells, as well as on CD45RA+ T cells ('revertants'), contributes to phenotypic heterogeneity in an autoimmune disease, namely WG. Upregulated CCR5 and CCR3 expression suggests that the cells belong to the effector memory T cell population. CCR5 and CCR3 expression on CD4+ and CD8+ memory T cells indicates a potential to respond to chemotactic gradients and might be important in T cell migration contributing to granuloma formation and vasculitis in WG.

CD4-Positive T-Lymphocytes↗