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Biomedical subjects

J Kekow

Publications and source records attributed to J Kekow.

At least 37 records · Page 2Linked to original sources
PubMed1997

Interaction of transforming growth factor beta (TGF beta) with proteinase 3.

TGF beta is a multifunctional cytokine modulating onset and course of autoimmune diseases as shown in experimental models. Aim of this study was to investigate possible interactions of TGF beta with lysosomal enzymes identified as ANCA autoantigens (e.g. proteinase 3, PR3). This included TGF beta effects on the translocation the lysosomal enzymes to the cell surface of polymorphonuclear cells (PMN), and the presumabe activation of non bioactive, latent TGF beta by these enzymes. Flow cytometry analysis showed TGF beta 1 to be a potent translocation factor for PR3 comparable with other neutrophil activating factors such as interleukin 8 (IL8). The 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. Patients with various types of systemic vasculitis (SV) showed marked TGF beta overexpression correlating with disease. Mean TGF beta 1 plasma levels in the ANCA associated vasculitis (AAV) patients ranged from 8.9 (Wegeners granulomatosis, WG) to 13.3 ng/ml (Churg-Strauss syndrome, CSS)(control: 4.2 ng/ml, p < 0.01) while TGF beta 2 levels were not elevated. Our findings, together with other features of TGF beta's 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.

Flow Cytometry↗
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↗
PubMed1995

Determination of transforming growth factor beta 2 in human blood samples by ELISA.

Transforming growth factors beta (TGF beta s) show pleotrophic functions in vitro and in vivo. Biological effects depend on the cell type, the TGF beta isoform, and the availability of active TGF beta. Bioassays for TGF beta have not proven to be reliable tools in the measurement of TGF beta in human blood samples. Previously described sandwich ELISAs for measuring TGF beta are limited to single TGF beta isoforms and have not been evaluated for use in human sera or plasma. We describe a simple procedure to quantitate not only TGF beta 1 but also TGF beta 2 in human blood samples using commercially available antibodies. The sensitivity of the TGF beta 2 ELISA was 11 pg/ml. There was no crossreactivity between the TGF beta 1 and TGF beta 3 isoforms. High concentrations of TGF beta 1 and TGF beta 3 in spiked samples did not interfere with TGF beta 2 determination. TGF beta 2 recovery was highest in EDTA plasma (> 88%), and the intra- and interassay variance was 6% and 8.5% respectively. Applying the ELISA to human plasma specimens a significant percentage of TGF beta 2 (3.7 +/- 0.8 ng/ml) was found (about 50% of the TGF beta 1 content).

Cross Reactions↗
PubMed1994

Serum antibodies to Klebsiella capsular polysaccharides in ankylosing spondylitis.

OBJECTIVE: To measure antibodies to Klebsiella capsular polysaccharides in the sera of HLA-B27 positive patients with ankylosing spondylitis (AS), compared with HLA-B27 positive and HLA-B27 negative healthy control subjects. METHODS: Antibodies were detected by means of an enzyme-linked immunosorbent assay specific for each of the 77 known Klebsiella serotypes. RESULTS: Significantly elevated frequencies and titers of antibodies to capsular polysaccharides K26, K36, and K50 were detected in sera from AS patients, compared with controls. CONCLUSION: These results suggest the predominance of Klebsiella serotypes K26, K36, and K50 in patients with AS.

Adult↗
PubMed1994

Influence of disease manifestation and antineutrophil cytoplasmic antibody titer on the response to pulse cyclophosphamide therapy in patients with Wegener's granulomatosis.

OBJECTIVE: To assess the effectiveness of pulse cyclophosphamide (CYC) in the treatment of Wegener's granulomatosis (WG) and to identify the patients who are responsive to the treatment. METHODS: The prospective study included 43 patients with biopsy-proven WG. Clinical, radiographic, laboratory, and immunologic data were evaluated for predictive values regarding the outcome of pulse CYC therapy. RESULTS: Only 42% of the patients showed complete or partial remission that lasted at least 6 months after cessation of pulse CYC therapy. These responders had a higher frequency of disease activity limited to the upper and lower respiratory tract (39%, versus 8% in the nonresponder group; P < 0.05) and had lower titers of classic antineutrophil cytoplasmic antibody (cANCA) prior to treatment (< 1:64 42%, versus 6% in the nonresponder group; P < 0.05). In the 58% of patients who did not respond to pulse CYC treatment, there was both systemic disease involving more than 4 organ systems (mainly, the heart, nervous system, eye, and skin) and constitutional symptoms. Serious side effects induced by pulse CYC occurred in only 1 patient. CONCLUSION: Based on these findings, pulse CYC therapy appears to be effective in WG patients with moderate disease activity and low titers of cANCA, but of little benefit in patients with severe WG. Pulse CYC should therefore not be used as first-line therapy in patients with severe and rapidly progressing forms of WG associated with high titers of cANCA.

Adolescent↗
PubMed1994

Comparison of the antibody responses to the 77 Klebsiella capsular types in ankylosing spondylitis and various rheumatic diseases.

The production of antibodies to Klebsiella capsular polysaccharides was measured in sera from either HLA-B27-positive (HLA-B27+) or HLA-B27-negative (HLA-B27-) patients with classical ankylosing spondylitis (n = 54). These sera were compared with sera from patients with various rheumatic diseases (n = 82) and HLA-B27+ or HLA-B27- healthy individuals (n = 85). All sera were analyzed by means of an enzyme-linked immunosorbent assay specific to each of the 77 Klebsiella serotypes. The sera from HLA-B27+ patients with ankylosing spondylitis showed a significantly higher antibody frequency to the capsular types K26, K36, and K50 than the sera from HLA-B27- ankylosing spondylitis patients, patients with psoriatic arthritis, systemic lupus erythematosus, rheumatoid arthritis, or reactive arthritis after Yersinia enterocolitica infection, or healthy controls (P < 0.02). The antibodies were of the immunoglobulin G type. No significant antibody response to the other 74 Klebsiella serotypes, noncapsulated mutants of K26, K36, and K50, or preparations of Citrobacter, Serratia, Hafnia, or Morganella spp. or Streptococcus pneumoniae could be detected. The results might suggest a specific association between these capsular types and HLA-B27+ ankylosing spondylitis and might imply their predominance in this disease.

Adolescent↗
PubMed1993

Pro- and anti-inflammatory cytokines in primary systemic vasculitis.

The expression of cytokines that are potentially involved in the pathogenesis of vasculitis was studied in patients with primary systemic vasculitis (PSV). In extension of earlier reports, we detected an overexpression of transforming growth factor beta (TGF beta), interleukin 6 (IL6), and interleukin 8 (IL8), indicating that the whole cytokine cascade is activated to a significant extent in PSV.

Churg-Strauss Syndrome↗
PubMed1993

Effectiveness of cyclophosphamide pulse treatment in Wegener's granulomatosis.

43 patients with Wegener's granulomatosis were studied to evaluate the effectiveness of cyclophosphamide (cyc) pulse treatment. 42% of the patients showed benefits from treatment for at least 6 months after the cessation of cyc pulses. Analysis of clinical and laboratory parameters indicate that this treatment is less effective in patients in whom more than 4 organ systems are involved. Responders to the treatment showed disease manifestations predominantly in the ENT and lower respiratory tract and had lower cANCA titers (< 1:64) prior to treatment.

Adolescent↗
PubMed1993

Autoantibodies to cartilage collagens in relapsing polychondritis.

Relapsing polychondritis is a systemic disease associated with a destruction of cartilage in various parts of the body. Sera from six patients with relapsing polychondritis and one patient with microscopic polyarteritis nodosa as well as from six controls were analyzed by immunoblotting and ELISA. All patients had autoantibodies against native collagens II and IX. The serum from one patient showed a strong reaction with all three collagen chains of the high molecular weight fraction of collagen IX after denaturation; sera from four patients showed autoantibodies against alpha 2 (XI) and sera from three patients showed autoantibodies against the covalently cross-linked gamma component of collagen XI. The presence of autoantibodies against collagens II, IX, and XI, which form the major fibrillar scaffold in cartilage and mediate the interaction of collagen fibrils and proteoglycan, suggests that autoantibodies against cartilaginous collagen may play a crucial role in the pathogenesis of relapsing polychondritis and microscopic polyarteritis nodosa.

Adult↗
PubMed1993

[Wegener's granulomatosis and ANCA-associated vasculitis: pathogenic role of autoantigens, autoantibodies, and cytokines].

A real explosion of data is seen concerning the detection of autoantibodies collectively known as antineutrophil cytoplasmic antibodies (ANCA) recognizing granule proteins of granulocytes and monocytes. Distinct fluorescence staining patterns result from their diverse substrate specificities, and can even identify several disease entities mainly in the etiopathogenetically unclear group of primary systemic vasculitides (PSV). The well-documented disease specificity of ANCA recognizing proteinase 3 (PR3), and recent in vitro findings concerning the effect of cytokines on immunocompetent cells including the endothelium are the rationale for the presentation of a new model explaining the development of systemic vasculitis.

Autoantibodies↗
PubMed1992

B-lymphocyte response in peripheral blood of patients with pulmonary sarcoidosis.

Sarcoidosis is a granulomatous disorder which can be characterized by various immunologic abnormalities including lymphocyte dysfunctions. The purpose of this study was to investigate the B-lymphocyte reactivity in the peripheral blood of 29 various patients with pulmonary sarcoidosis. A significant decrease in the production of IgG, IgM and IgA in supernatants of cultivated sarcoidosis B-cells both after stimulation with a T-cell dependent polyclonal B-cell activator (pokeweed mitogen) and with a T-cell independent polyclonal B-lymphocyte activator (Klebsiella pneumoniae) was seen, which suggested a disturbance in the B-cell differentiation of sarcoidosis patients. Those patients which were known to have a clinically active disease or a high intensity alveolitis in the bronchoalveolar lavage fluid showed a greater reduction in the B-cell differentiation response. Further evaluation of Ig-G subclasses displayed a significant decrease in the secretion of IgG1, IgG3 and IgG4. In contrast to the differentiation, the proliferation response of sarcoidotic peripheral blood lymphocytes to different mitogens did not differ from healthy controls.

Adult↗
PubMed1992

[Elevated serum levels of ICAM-1 in Wegener's granulomatosis].

Circulating soluble ICAM-1 (sICAM-1) isoforms are known to be elevated in inflammatory and autoimmune disorders (SLE, RA). A correlation between levels of circulating sICAM-1 and disease activity was described (5). In sera from 31 patients suffering from histologically confirmed Wegener's granulomatosis (WG) elevated levels of ICAM-1 were now detected in this primary systemic vasculitis. In generalized active disease circulating ICAM-1 levels were significantly higher when compared to remission and healthy control individuals. Sera from WG patients collected during intercurrent infections while on immunosuppressive drugs showed no elevation of circulating ICAM-1.

Antigens, CD↗
PubMed1991

Transforming growth factor-beta and suppression of humoral immune responses in HIV infection.

We reported previously that PBMC from HIV+ patients spontaneously release increased levels of TGF beta 1, contributing to defects in cellular immune responses. This study defines the implications of TGF beta overexpression for humoral immunity in HIV infection. We found that upon Staphylococcus aureus Cowan I (SAC) stimulation of cells from HIV+ donors, B-lymphocyte proliferative responses were decreased. This deficiency correlated closely (r = 0.7, P less than 0.001) with increased TGF beta secretion by PBMC from HIV-infected donors. Conditioned medium from HIV+ PBMC and purified TGF beta 1 had similar inhibitory effects on SAC- or EBV-induced B-cell proliferation, and B cells from HIV-infected donors were as sensitive to inhibition by TGF beta as cells from normal donors. Antibodies to TGF beta 1 neutralized the inhibitory effect of HIV+ culture supernatants on normal B cells and increased low proliferative responses by HIV+ cells. Using PWM as stimulus for B cell differentiation, it was shown that activated TGF beta from HIV+ PBMC is able to significantly reduce the induction of immunoglobulins and this effect was also abrogated by anti-TGF beta. These studies support the concept that in HIV infection, TGF beta is a potent suppressor, not only of the cellular, but of the humoral immune responses as well.

Antibody Formation↗