Biomedical subjects

G J Lafeber

Publications and source records attributed to G J Lafeber.

At least 19 recordsLinked to original sources

PubMed1990

Bisphosphonates in collagen arthritis.

Bisphosphonates suppress bone destruction in various diseases. We studied the effects of 3-amino-hydroxypropylidene-1,1-bisphosphonate (APD), and dimethyl-APD in the collagen model of chronic arthritis in rats. The incidence and severity of arthritis was not lower in rats treated with APD or dimethyl-APD compared with controls. The cellular and humoral immune responses to collagen were also similar in the treated and untreated animals. In all animal groups the same bone destruction was found radiographically 42 days after immunization. This study demonstrates that bisphosphonates do not suppress the course of collagen arthritis in rats.

Animals↗

PubMed1989

Anti-endothelial cell antibodies in patients with rheumatoid arthritis complicated by vasculitis.

IgG antibodies reactive with human umbilical vein endothelial cells were found in 19 out of 28 patients with rheumatoid vasculitis (RV), in four out of 24 patients with rheumatoid arthritis (RA), in seven out of 10 patients with systemic lupus erythematosus (SLE), but not in healthy donors. In four patients with RV who were followed longitudinally, regression of vasculitic episodes coincided with decreasing titres of anti-endothelial antibodies (AEA). Binding activity to endothelial cells was observed in intact IgG and F(ab')2 fragments of IgG. AEA activity was unrelated to antibodies against nuclear, blood group or major histocompatibility complex antigens and did not involve immune complexes. AEA activity was not specific for endothelial cells since the AEA-positive sera and the IgG fractions prepared from these sera also reacted with fibroblasts. Adsorption of positive sera and corresponding IgG fractions with endothelial cells decreased the IgG binding reactivity on both fibroblasts and endothelial cells. These findings show that RV patients have IgG-AEA, and suggest that these antibodies may play a role in the pathogenesis of the disease.

Antibody Specificity↗

PubMed1988

Immune complexes in sera from patients with rheumatoid vasculitis induce polymorphonuclear cell-mediated injury to endothelial cells.

The ability of sera from 11 patients with rheumatoid arthritis (RA) complicated by leukocytoclastic vasculitis (RV) to induce injury to cultured monolayers of human umbilical vein endothelial cells (HEC) was investigated. Injury was assessed in vitro using assays of cell lysis and cell detachment. Sera from patients with RV produced neither direct injury to HEC monolayers nor indirect injury when cocultured with HEC and normal peripheral blood polymorphonuclear cells (PMN). However, immune complexes (Icx) isolated from these sera induced nonlytic PMN-mediated HEC detachment. The inhibitory effect of serum on PMN-mediated HEC detachment induced by Icx could be attributed both to a different response of PMN to Icx present in serum compared to isolated Icx and to the presence of protease inhibitors in serum. The results of this study show that sera from patients with RV do not contain factors that can injure HEC directly and provide further support for the hypothesis that Icx and PMN play important roles in the pathogenesis of immune vascular injury.

Adult↗

PubMed1987

Elastase and collagenase activities in synovial fluid of patients with arthritis.

The activity of elastase and collagenase was measured in the synovial fluid (SF) of 24 patients with inflammatory and 6 patients with traumatic joint effusions. The enzyme activity was compared with local and systemic variables of the disease. Elastase and collagenase activity could be detected in 79 and 83%, respectively, of the arthritic SF, whereas no enzyme activity was found in the traumatic joint effusions. The SF enzyme activity showed no correlation with clinical, laboratory or radiographic variables of arthritis in the joint from which the fluid was obtained. Our results show that proteolytic enzyme activity in SF may help to distinguish inflammatory from noninflammatory joint effusions but does not reflect the severity of the arthritic process.

Arthritis↗

PubMed1986

Phagocytosis and intracellular killing of Staphylococcus aureus by polymorphonuclear cells from synovial fluid of patients with rheumatoid arthritis.

The phagocytosis and intracellular killing by synovial fluid (SF) polymorphonuclear cells (PMN) of 10 patients with rheumatoid arthritis was studied. PMN phagocytosis was assessed by morphologic and microbiologic methods and intracellular killing was measured independently of continuous phagocytosis of Staphylococcus aureus. Phagocytosis of S aureus by SF PMN or peripheral blood (PB) PMN was as effective in the presence of synovial fluid as in the presence of serum. On average, SF PMN ingested S aureus opsonized with synovial fluid and serum more efficiently than patient or donor PB PMN did. Enhanced ingestion of S aureus was associated with increased expression of C3 receptors on the membrane of SF PMN. In the presence of heat-inactivated synovial fluid, the capacity of SF PMN to ingest S aureus was greater than that of patient or donor PB PMN. Under these conditions, phagocytic activity was correlated with Fc receptor expression. SF PMN was found to be as active in killing S aureus as PB PMN from healthy donors.

Analysis of Variance↗

PubMed1986

Immune complexes and the pathogenesis of neutropenia in Felty's syndrome.

The effect of the injection of serum from patients with rheumatoid arthritis (RA) and Felty's syndrome (FS) into mice on the number of circulating polymorphonuclear cells (PMN) was studied. The number of circulating PMN dropped to 61% (range 34-98%) of the initial counts after the injection of FS serum. This phenomenon was observed less frequently after injection of RA serum. In contrast, injection of serum from healthy controls always resulted in an immediate increase in the number of circulating PMN. No decrease in PMN counts was found after injection of FS sera pretreated with polyethylene glycol to precipitate immune complexes (IC). Gel filtration of FS sera on Sepharose 4B showed that the effect on the PMN counts in mice did not coincide with the 7S peak but occurred only in fractions containing larger material. Serum fractions from FS patients that contained IC were more active in producing neutropenia than the corresponding fractions from patients with RA. Microscopic and immunohistochemical examination of the organs from mice injected with FS serum showed sequestration of PMN and deposition of human IgG, IgA, and IgM in the vascular bed of the lungs. These results indicate that the interaction between PMN and IC of patients with FS leads to sequestration of PMN in mice and suggests that this interaction in humans may have a role in the pathogenesis of FS.

Aged↗

PubMed1985

Felty syndrome: autoimmune neutropenia or immune-complex-mediated disease?

Immunofluorescence on polymorphonuclear cells (PMN) of patients with Felty syndrome (FS) revealed increased amounts of IgG, IgA, and IgM bound to the PMN surface compared with PMN of patients with rheumatoid arthritis alone. A positive correlation was found between the score for surface-bound immunoglobulins on FS-PMN and the results of the Clq binding assay in FS sera. After preincubation with sera from 20 patients with FS, immunofluorescence on PMN from healthy controls (HC) showed that these cells had bound IgG, IgA, and IgM. However F(ab')2 fragments of IgG from FS sera did not bind to PMN, although the antigen-binding reactivity of the F(ab')2 fragments was maintained as shown by control experiments. Immunoglobulins eluted from FS-PMN failed to bind to HC-PMN, whereas the corresponding IgG of patients with autoimmune neutropenia was bound. Gel filtration of FS sera on Sepharose 4B showed that the binding of IgG in FS sera to PMN did not coincide with the 7S peak but occurred mainly in fractions containing larger material. No binding of IgA and IgM to HC-PMN was found after incubation with FS sera pretreated with polyethylene glycol (PEG) to precipitate immune complexes. These results indicate that in sera of patients with FS the PMN-binding reactivity of IgG, IgA, and IgM is due to the binding of immune complexes containing these immunoglobulins and not to presence of autoantibodies directed to antigens on the neutrophil surface.

Antigen-Antibody Complex↗

PubMed1984

Lymphocyte subpopulations in rheumatoid arthritis. An immunological, enzyme histochemical and morphological study.

Peripheral blood lymphocytes (PBL) and synovial fluid lymphocytes ( SFL ) of patients with rheumatoid arthritis (RA) were examined with monoclonal antibodies, with coated ox red blood cells for the expression of Fc receptors for IgG or IgM (T mu and T gamma cells), and incubated for the demonstration of alpha- naphtyl acetate esterase and acid phosphatase. Equal percentages of OKT4 and OKT8 PBL were found in clinically active and inactive RA patients, and in healthy controls, but decreased percentages of OKT4 and increased percentages of OKT8-positive lymphocytes were found among the SFL . The percentages of T mu and T gamma cells, the presence of HLA-DR membrane antigens on T lymphocytes as well as the staining pattern for the enzymes revealed that SFL of patients with RA were highly activated, compared to PBL of RA patients and healthy controls. It can be concluded from this study that a single determination of OKT4 and OKT8-positive lymphocytes in the peripheral blood of RA patients has no predictive value for disease activity. However, the results of the experiments on T lymphocyte-activation clearly showed preferential activation of SFL compared to PBL, indicating that activation of lymphocytes occurs at the site of inflammation.

Antibodies, Monoclonal↗

PubMed1984

Fc receptors on granulocytes from patients with rheumatoid arthritis and Felty's syndrome.

Receptors for the Fc part of IgG on polymorphonuclear cells (FcR) of patients with rheumatoid arthritis (RA), Felty's syndrome (FS) and healthy controls (HC) were studied by means of a rosetting technique with rabbit IgG coated ox erythrocytes. When cold isolated polymorphonuclear cells (PMN) were incubated at room temperature the percentage of rosette forming PMN (RF-PMN) from HC was more than twice that measured directly after isolation at 4 degrees C. The same phenomenon was observed for PMN from patients with RA although the RF-PMN increased by only 1/3. In contrast warming of PMN from patients with FS did not influence the RF-PMN. The presence of surface bound immunoglobulins and intracytoplasmic immunoglobulins was measured by immunofluorescence and appeared to be inversely related to the RF-PMN. A good correlation between the results of the C1q binding assay (C1qBA) and the immunofluorescence score was observed but no correlation existed between the C1qBA and the RF-PMN. These results indicate that the number of PMN expressing FcR in patients with RA and FS is decreased presumably because of the phagocytosis of immune complex like material. The decrease in the availability of FcR may influence the functions of the PMN.

Antigen-Antibody Complex↗

PubMed1984

C3 receptors on granulocytes from patients with rheumatoid arthritis and Felty's syndrome.

The expression of receptors for the third component of complement (C3R) on polymorphonuclear cells (PMN) from patients with rheumatoid arthritis (RA) or Felty's syndrome (FS) and healthy controls (HC) was studied by means of a rosetting technique using ox erythrocytes coated with rabbit IgM and mouse complement. The percentage of rosette forming PMN (RF-PMN) was found to be increased in patients with FS (59%) and patients with RA (47%) compared to HC (18%), when measured directly after cold isolation of PMN. Incubation at 37 degrees C of cold isolated cells increased the percentage of RF-PMN in all three groups, although the values were significantly higher during the first 45 min of incubation in both patient groups. When incubated with serum from patients with FS at 37 degrees C, cold isolated donor PMN formed significantly more rosettes than after incubation with donor serum. This increase was shown to be due to the presence of circulating immune complexes in the patient sera and could be mimicked by incubating donor PMN with aggregated human IgG. As a result of these experiments it was demonstrated that the increased percentages of PMN with C3R in patients with FS or RA are most likely caused by a previous in vivo activation of PMN by immune complexes. The possible effect of such an increase in C3R expression in relation to PMN function in these patients is discussed.

Antigen-Antibody Complex↗

PubMed1983

The significance of immunofluorescent immunoglobulin inclusions in polymorphonuclear leucocytes for the detection of circulating immune complexes.

Cytoplasmic inclusions of immunoglobulins and complement, detected by fluorescent antibodies in polymorphonuclear leucocytes (PMNs) that have been incubated with sera of certain patients, are considered to represent immune complexes (IC). The usefulness of this test--the indirect PMN phagocytosis test (IPPT)--for the detection of circulating IC was investigated using preparations of free and heat-aggregated immunoglobulins. Free IgG and IgM were phagocytozed by PMNs at high concentrations only, while free IgA was not phagocytozed at all. Normal human serum slightly enhanced the uptake of free IgG and IgM, but not of free IgA. Aggregates of IgG and IgA underwent phagocytosis at low concentrations, but IgM aggregates were not taken up more readily than free IgM. The uptake of IgG aggregates decreased in the presence of serum, while there was no influence upon the phagocytosis of IgA aggregates. Phagocytosis of C3 occurred only with IgG aggregates. In the presence of aggregates of IgG or IgA the phagocytosis of free immunoglobulins of other classes, in particular IgM, increased. The results of the IPPT for patients' sera showed that inclusions of C3 were found more frequently in combination with IgA or IgM than with IgG. Comparison with the 125I-Clq binding assay and the anti-IgA inhibition binding assay disclosed significant correlation between the phagocytosis of IgG and the precipitation of 125I-Clq and between the phagocytosis of IgA and the results of the anti-IgA inhibition binding assay. The PMN phagocytosis test may be useful for the detection of IgG and IgA containing IC but inclusion of IgM and C3 should be interpreted with some reserve.

Antigen-Antibody Complex↗

PubMed1982

Autoantibodies against Tmu and B lymphocytes in patients with rheumatoid arthritis.

Patients with rheumatoid arthritis have decreased numbers of T mu lymphocytes in their peripheral blood. To find out whether these low number of T mu lymphocytes were associated with the presence of anti-lymphocyte antibodies, the sera of 27 patients with definite or classical rheumatoid arthritis (RA) were investigated for the presence of autoantibodies against subsets of lymphocytes. In addition the numbers of T, T mu, T gamma and B lymphocytes in the peripheral blood of these patients were investigated. Patients with active RA showed lower numbers of T mu lymphocytes in their peripheral blood than patients with inactive RA. However, both groups of RA patients had significantly decreased numbers of T mu lymphocytes in their peripheral blood as compared with 22 age matched healthy donors. Moreover, mainly in patients with active RA cold reactive antibodies were found directed against T mu and B lymphocytes, but never against T gamma lymphocytes of healthy donors. Similar results were found in the indirect immunofluorescence procedure when tested for reactivity against T-cell subsets. This serum reactivity was not caused by rheumatoid factors or antinuclear antibodies. Since RA sera after precipitation with 2.5% polyethyleneglycol, still showed cytotoxicity against T and B lymphocytes, it is suggested that this serum reactivity is not caused by immune complexes but by antibodies.

Adult↗

PubMed1981

Presence of immune complex-like material in sera of patients with paraproteinaemia.

Immunoglobulins of all classes as well as C3 are phagocytosed by normal human granulocytes from sera containing paraproteins. The material that was phagocytosed had the sedimentation properties of immune complexes. Cytostatic treatment did not seem to have a clearcut influence on the presence or absence of these complexes. There was little correlation with two other immune complex detecting tests. The Clq binding test was frequently found positive in paraproteinaemic sera but without apparent correlation to IgG phagocytosis. On the other hand the conglutinin binding test was rarely positive, although C3 was frequently phagocytosed.

Antigen-Antibody Complex↗

PubMed1980

Mixed rosette assay for the detection of T mu and T gamma lymphocytes.

A mixed rosette assay is described for simultaneous detection of T lymphocytes and lymphocytes bearing receptors for the Fc Fragments of IgM (RFc mu) or IgG (RFc gamma) in unfractionated lymphocyte suspensions. For optimal detection of T lymphocytes, treatment of sheep erythrocytes with neuraminidase was necessary. ox erythrocytes labelled with fluorescein isothiocyanate and sensitized with either rabbit IgM or rabbit IgG anti-ox antibodies served as indicator erythrocytes for RFc mu or RFc gamma bearing lymphocytes. In periphral blood the percentage of RFc mu bearing lymphocytes was the same whether determined directly after isolation or after overnight incubation at 37 degrees C. Ratios of non-fluoresceinated sheep erythrocytes to senanti-ox antibodies served as indicator erythrocytes for RFc mu or RFc gamma bearing lymphocytes. In periphral blood the percentage of RFc mu bearing lymphocytes was the same whether determined directly after isolation or after overnight incubation at 37 degrees C. Ratios of non-fluoresceinated sheep erythrocytes to senanti-ox antibodies served as indicator erythrocytes for RFc mu or RFc gamma bearing lymphocytes. In periphral blood the percentage of RFc mu bearing lymphocytes was the same whether determined directly after isolation or after overnight incubation at 37 degrees C. Ratios of non-fluoresceinated sheep erythrocytes to sensitized fluoresceinated ox erythrocytes are critical in the mixed rosette assay; for simultaneous detection of T lymphocytes and RFc mu bearing lymphocytes 1 : 1, and for T lymphocytes and RFc gamma bearing lymphocytes 2 : 1. In both assays the rosette suspension was preincubated for 10 min at 37 degrees C and then centrifuged at 200 X g for 5 min. For optimal simultaneous detection of T lymphocytes and RFc mu bearing lymphocytes incubation at room temperature for at least 2 h was necessary and for T lymphocytes and RFc gamma bearing lymphocytes incubation at room temperature for at least 2 h was necessary and for T lymphocytes and RFc gamma bearing lymphocytes incubation at 4 degrees C for at least 2 h was essential. The percentages of RFc mu or RFc gamma bearing lymphocytes (T mu and T gamma respectively) in the T lymphocyte population determined by mixed rosette assay did not differ significantly from the percentages of RFc mu and RFc gamma bearing lymphocytes in lymphocyte suspensions enriched in T cells by E-rosette sedimentation. The mixed rosette assay is suitable for detection of T mu and T gamma cells in immune deficiency and auto-immune diseases and for analysis of the mononuclear cells in lymphoreticular malignancies.

Animals↗

PubMed1980

Membrane and transformation characteristics of lymphocytes isolated from the synovial membrane and paired peripheral blood of patients with rheumatoid arthritis.

Membrane and transformation characteristics of lymphocytes isolated from the synovial membrane and from paired peripheral blood samples, obtained from patients with classical rheumatoid arthritis, were studied. Synovial tissue lymphocytes were isolated by a new technique. Two suspensions of peripheral blood lymphocytes were studied: one isolated by Ficoll-Isopaque density gradient centrifugation, the other enriched in T cells by an additional step of 1 hour nylon wool column filtration. All suspensions were characterised by the percentages of mononuclear phagocytic cells, and T and B lymphocytes. The spontaneous (3)H-thymidine uptake of synovial tissue lymphocyte suspensions always exceeded that of the peripheral blood lymphocyte suspensions. The in-vitro responsiveness of synovial tissue lymphocytes to PHA, Con-A, and PWM, as measured by (3)H-thymidine uptake, was always consistently lower than that of paired peripheral blood lymphocytes whether or not enriched in T cells. The responsiveness to antigens, including PPD, varidase, and an antigen cocktail consisting of varidase, trychophyton, and Staphylococcus aureus antigen, showed the same effect. No dissociation was found between the response to PPD and the other antigens studied. These results suggest that the relative unresponsiveness to mitogens and antigens of synovial tissue lymphocytes in comparison with blood lymphocytes is not caused by mononuclear phagocyte contamination, but either by different subsets of T lymphocytes or by different functional states of T lymphocytes present in the synovial membrane and peripheral blood of patients with rheumatoid arthritis.

Antigens↗

PubMed1980

Pokeweed-mitogen induced lymphocyte proliferation: the effect of stimulation on mononuclear phagocytic cells.

Human peripheral blood mononuclear cells were stimulated with pokeweed mitogen (PWM) to study the role of mononuclear phagocytic cells (MNP) in lymphocyte proliferation. MNP were identified by cytoplasmic alpha-naphthyl acetate esterase, by the capacity of phagocytosis and by lysozyme synthesis. It appeared that after 3 days of stimulation with PWM all MNP disappeared from the cultures and remained absent during prolonged culture in mitogen-free medium. In non-stimulated cultures MNP remained. The disappearance of MNP from cell cultures was caused by a lymphocyte-derived factor, which was transferable by cell-free supernatants of stimulated mononuclear cells. From experiments in which cultures were treated with different concentations of PWM and from pre-culture experiments, it could be shown that in vitro lymphocyte proliferation required both non-stimulated lymphocytes and freshly prepared MNP. In addition, the decreasing concentration of PWM as stimulating agent, resulted in a decreasing proliferation of lymphocytes, which was inversely proportional to the presence of MNP.

Cell Division↗

PubMed1978

Lymphocyte isolation from chronically inflamed synovial membranes.

A simple two-step procedure was developed for isolation of lymphocytes from chronically inflamed human synovial membranes. In the first step minced inflamed synovial tissues are disrupted enzymatically by deoxyribonuclease and collagenase. The second step consists of nylon-wool column filtration of the isolated cells. 7 min of preincubation of up to 37.4 X 10(6) cells in a column packed with 600 mg nylon-wool in 6 ml prior to filtration did not result in significant selective losses of either T or B cells, whereas 45 min of preincubation did. Recovery of lymphocytes after nylon-wool column filtration ranged from 68 to 95% (mean 80%) and viability was always higher than 90%. Nylon-wool column filtration increased the proportion of lymphocytes by a mean 73%. The method allows rapid identification of synovial tissue lymphocyte subpopulations as well as characterization of their function.

Adult↗

PubMed1977

Atypical T cells in rheumatoid synovial membranes.

Atypical mononuclear cells (AMC) with Sézary-cell-like morphology were demonstrated to be present in rheumatoid synovial membranes. These cells have exclusively T cell membrane characteristics, like identical cells previously found in rheumatoid synovival fluids. AMC were predominantly present in transitional areas between nodular lymphocytic aggregates and plasma cell rich areas. In ultrathin sections AMC accounted for approximately 30% of all lymphocyte cells; in studies of cells isolated from rheumatoid synovial membranes AMC comprised 30--40% of the E-rosette-forming cells. The hypothesis that these cells represent reactive T cells is discussed.

Arthritis, Rheumatoid↗