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Biomedical subjects

M Ziff

Publications and source records attributed to M Ziff.

At least 73 records · Page 4Linked to original sources

IgG and IgM rheumatoid factors in rheumatoid arthritis. Quantitative response to penicillamine therapy and relationship to disease activity.

Penicillamine treatment of patients with rheumatoid arthritis (RA) leads to falling titers of agglutinating IgM rheumatoid factor (RF), but its effect on IgG RF has not been described. Using specific solid phase radioimmunoassays, we have determined serial levels of IgM RF and IgG RF in 18 patients receiving penicillamine for 1 year, and correlated the results with the change in RA activity. Mean IgM RF levels fell to 76 +/- 10% (mean +/- SEM) after 3 months, and 30 +/- 5% of the pretreatment value after 1 year of penicillamine treatment. This decline was greater than that for total IgM (P less than 0.0001), indicating a selective reduction of RF. Patients receiving maintenance doses of 750 mg/day manifested more rapid and greater decreases than did those given 250 mg/day. In contrast, serial mean IgG RF levels did not change significantly, and actually increased in 6 of 18 cases. At onset, there was a significant correlation with erythrocyte sedimentation rate for both IgM RF (r = 0.535, P = 0.05) and IgG RF levels (r = 0.570, P = 0.02). But changes in RF concentration demonstrated no correlation with changes in either erythrocyte sedimentation rate or joint score over the 1-year period, suggesting that circulating IgM RF or IgG RF levels may be unrelated to the degree of RA activity.

Adult↗

Immunoelectron microscopic demonstration of fibronectin in rheumatoid pannus and at the cartilage-pannus junction.

The presence of fibronectin (Fn) in rheumatoid pannus was investigated by an immunoelectron microscopic method using horseradish peroxidase-conjugated antibody to stain Fn. Large amounts of Fn were demonstrated in the interstitial collagenous tissue of invasive rheumatoid pannus. Fn was also observed on the surface of both fibroblast-like and macrophage-like pannus cells, suggesting that it was secreted by these cells and that the secreted Fn might facilitate the spreading of the pannus cells over the cartilage matrix. However, decreased amounts of Fn were observed in areas of contact between pannus cells and the cartilage matrix. The reduction in the amount of Fn demonstrable at the cartilage-pannus junction may be a consequence either of proteolysis of Fn by enzymes secreted at the junction, inhibition of Fn synthesis in cells in contact with cartilage matrix, or transfer of Fn from the pannus cell surface to collagen of the cartilage matrix.

Arthritis, Rheumatoid↗

Immunomodulatory effect of procainamide in man. Inhibition of human suppressor T-cell activity in vitro.

Procainamide (PA) induces the production of a number of autoantibodies in a high proportion of treated individuals and in some a syndrome closely resembling systemic lupus erythematosus. The mechanism underlying this action of PA is unclear. To examine the possibility that PA might induce autoantibody formation by altering normal immunoregulatory mechanisms, the action of this drug on an in vitro model of antibody formation in man was examined. PA was found to augment the generation of immunoglobulin-secreting cells (ISC) from human peripheral blood mononuclear cells (PBM) in response to pokeweed mitogen but had no effect on pokeweed mitogen-induced tritiated thymidine incorporation. When purified populations of B and T cells were used, PA enhanced the generation of ISC in B-cell cultures supported by untreated T cells but not by T cells treated with mitomycin C. These results indicate that PA augmented B-cell responses by inhibiting suppressor T-cell activity and not by augmenting helper T-cell or B-cell function. N-Acetyl-procainamide had no effect on the generation of ISC in this system. The effect of PA on concanavalin A (Con A)-induced suppressor cell activity was also examined to determine whether PA altered the generation or expression of suppressor T-cell function. PBM were cultured with 30 microgram/ml of Con A for 48 h to generate suppressor cells. When these were co-cultured with fresh PBM, the number of ISC generated was decreased by 58.1 +/- 3.4% (mean +/- SEM, n = 6). Cells that had been similarly incubated without Con A were not inhibitory. The addition of PA to the Con A-stimulated cultures inhibited the generation of suppressor cells as indicated by the fact that the response of fresh cells co-cultured with the Con A-stimulated cells was diminished by only 27.2 +/- 4.3%. In this system too, N-acetyl-procaimamide had no effect. By contrast, adding PA only to the co-culture of Con A-stimulated cells with fresh PBM had a less marked effect on suppressor cell function. These results indicate that the major action of PA is to inhibit the generation of suppressor T-cell activity. Such an effect may explain the capacity of this agent to induce autoantibody formation in treated individuals.

Antibody Formation↗

Factors involved in cartilage injury.

The cellular and humoral mechanisms whereby the synovial membrane can bring about the degradation of the cartilage in the rheumatoid joint are discussed.

Animals↗

Increased endothelial cell adherence, aggregation, and superoxide generation by neutrophils incubated in systemic lupus erythematosus and Felty's syndrome sera.

The ability of sera from patients with systemic lupus erythematosus (SLE) and Felty's syndrome to induce increased adhesiveness of normal human neutrophils (PMN) was investigated. PMN from normal healthy donors were incubated in sera from 19 patients with active SLE, 12 with inactive SLE, 20 with Felty's, 24 with rheumatoid arthritis, and 34 normal persons. After incubation, the degree of adherence of the PMN to human endothelial cells in culture, their aggregation, and superoxide (O2-) generation were determined. Sera from patients with both active SLE and Felty's syndrome induced significantly increased PMN adherence to endothelial cells and PMN aggregation in vitro, compared with normal sera. This increased adherence to endothelial cells was maintained after heat treatment (56 degrees C for 30 minutes) of the sera. In O2- generation experiments, sera from patients with active SLE induced significantly increased O2- release from normal PMN using both fresh and heat-treated sera. Sera from Felty's patients demonstrated the same effect with heat-treated sera but not ith fresh sera. When sera from patients with active SLE and Felty's syndrome were used, all three parameters correlated significantly with each other in individual patients. In contrast, sera from the 12 patients with inactive SLE and 24 rheumatoid arthritis patients without Felty's failed to induce significant differences in the three parameters studied when compared with 34 normal controls. Fractionation of 3 SLE sera and 1 Felty's serum on Sephadex G-200 demonstrated that the adherence enhancing factor was present in both IgG and IgG-excluded fractions. The observed increased adhesiveness of PMN induced by SLE and Felty's sera may, at least in part, contribute to the neutropenia which is common in these diseases. Increased O2- release associated with PMN adherence may contribute to endothelial cell damage and vascular injury, which is also a common manifestation of these diseases.

Adult↗

In vitro synthesis of immunoglobulins and IgM-rheumatoid factor by blood mononuclear cells of patients with rheumatoid arthritis.

In vitro synthesis of IgG, IgM and IgM-rheumatoid factor (IgM-RF) was investigated in unstimulated and pokeweed mitogen (PWM)-stimulated 7-day cultures of blood mononuclear cells (BMC) from 28 seropositive patients with active rheumatoid arthritis (RA), in a second group of 13-day cultures from 94 unselected rheumatoid patients, and in 21 healthy controls. Both normal and rheumatoid BMC cultures synthesized IgM-RF in response to PWM stimulation. Mitogen-induced stimulation was shown to be dependent on the presence of T-lymphocytes. PWM-induced IgM and IgM-RF synthesis were reduced in BMC from rheumatoid patients in comparison with healthy controls. However, the fraction of IgM-RF in the total IgM synthesized was significantly higher in the RA supernatants than in the controls, suggesting the presence of a larger precursor B-cell population committed to IgM-RF synthesis in those cultures. BMC from 44 of the 94 patients demonstrated spontaneous synthesis of IgM-RF, and this was positively correlated with disease activity and rheumatoid factor titer. Spontaneous production was shown to reside in the T-lymphocyte depleted, adherent cell-depleted, B-cell subpopulation. It is concluded that in active RA there is a specific activation and expansion of the circulating B-cell subpopulation committed to IgM-RF synthesis, possibly due to abnormal immunoregulatory mechanisms modulating synthesis of this antibody.

Adult↗

Quantitation of rheumatoid factor by laser nephelometry.

Laser nephelometry is a sensitive technique for measuring the degree of light scatter caused by the interaction of rheumatoid factors with heat aggregated human IgG. In measuring the rheumatoid factor (RF) level in rheumatoid serum and synovial fluid, it was found that nephelometry measured the combined amounts of IgM-RF and IgG-RF. However, on an equivalent weight basis, IgM-RF produced at least 17 times more scatter than IgG-RF. Low molecular weight IgM-RF had minimal light scattering activity in this assay. The total serum RF level, measured by nephelometry and expressed in terms of microgram/ml of IgM-RF equivalents, correlated strongly with IgM-RF measured by solid phase radio-immunoassay (r = 0.97, n = 30, P less than 0.001) and an equation was derived to equate the two variables. It is concluded that the nephelometric RF test is a simple and rapid method to measure the total polyclonal RF level in various biological fluids, although monoclonal or an occasional polyclonal preparation of rheumatoid factor may give atypical results.

Humans↗

Immunopathogenesis of rheumatoid arthritis.

Three distinct groups of phenomena occur in the rheumatoid joint. The synovial lining cells proliferate and hypertrophy; the sublining or deep layer becomes infiltrated by mononuclear cells; and fluid, which is rich in polymorphonuclear cells, collects in the synovial space. As a result, there is a polymorphonuclear inflammatory reaction in the rheumatoid effusion and a chronic inflammatory reaction in the sublining layer of synovial membrane. In spite of their divergent histologic character, these two inflammatory reactions appear to be interrelated immunologically. In this review, we describe these two types of inflammation, trace their interrelationship and consider possibly underlying mechanisms for the inflammation.

Arthritis, Rheumatoid↗

Hidden anti-double stranded DNA antibodies in autoimmune mice.

When MRL/l mouse spleen cell culture supernatants were incubated with normal mouse spleen cells, a two-50-fold increase in anti-dsDNA activity was noted. A smaller increase in anti-ssDNA and no change in anti-TNP antibody activity were observed. This 'hidden' antibody in the MRL/l supernatants could not be revealed by DNAse digestion and could not be absorbed by a DNA cellulose column. Hidden antibody was removed from supernatants by sepharose-anti Ig. After DNAase digestion of the MRL/l supernatants, hidden anti-dsDNA could not be revealed by incubation with spleen cells. All the hidden activity was excluded by gel filtration on Sephacryl S-300 (mol. wt greater than 300,000) but was banded in the low density protein area of caesium chloride equilibrium density gradients. It was also noted that MRL/l mouse sera had hidden anti-dsDNA antibodies. Hidden antibodies were present in both the IgG and IgM classes. The revealed antibodies demonstrated impaired ability to bind Fc specific anti-Ig reagents suggesting that they were partially degraded during the incubation with mouse spleen cells. The hidden anti-dsDNA thus appears to represent a DNA-anti-dsDNA complex, perhaps of very high affinity. It may explain why anti-dsDNA but not anti-ssDNA antibodies are of pathological importance in SLE.

Animals↗

The in vitro and in vivo induction of anti-double-stranded DNA antibodies in normal and autoimmune mice.

To determine whether the existence of anti-dsDNA producing lymphocyte clones is limited to autoimmune strains of mice, spleen cells derived from autoimmune mice (NZB, NZB X NZW F1, MRL) and from normal strains (BALB/c, DBA/2, C57BL/6, C3H/eb) were cultured with E. coli lipopolysaccharide (LPS). DNase-treated supernatants from these cultures were assayed for anti-dsDNA antibodies by employing a sensitive solid-phase radioimmunoassay with poly (dA-dT) as the antigen. All tested spleen cells secreted a small yet significant amount of anti-dsDNA upon stimulation with LPS. There was no difference in the amount or in the heavy chain type of anti-dsDNA secreted by cells from normal and autoimmune strain cells. Evidence of clonal expansion in unstimulated cells was observed only in cultures prepared from older autoimmune animals. Removal of T cells from the spleen cell preparations had no marked effect on the spontaneous or stimulated antibody secretion. Anti-dsDNA antibodies could also be induced in vivo by i.p. injection of LPS into young normal animals. Splenocytes from all tested strains spontaneously secreted anti-ssDNA and anti-TNP antibodies in culture, and these were present at relatively high levels in the serum of unstimulated animals. Stimulation with LPS increased secretion of anti-ssDNA and anti-TNP in all strains in vitro and in five of seven strains in vivo as well. It can be concluded that a) the existence of anti-dsDNA-producing clones is not limited to autoimmune strains, and b) these clones are expanded in old but not in young autoimmune mice. They are not expanded in normal mice at any age.

Aging↗

A sensitive solid phase microradioimmunoassay for anti-double stranded DNA antibodies.

A sensitive solid phase microradioimmunoassay has been developed for measurement of antidouble stranded DNA (dsDNA) antibodies. In this procedure, advantage has been taken of the capacity of poly-L-lysine (PLL) to facilitate the binding of pure dsDNA to plastic surfaces. In the absence of PLL, binding did not occur. Diluted sera were incubated in PLL-treated dsDNA-coated microtitration trays and anti-dsDNA Ig measured using affinity purified 125I-anti-Ig of high specific activity. The synthetic DNA, poly dA-dT, was used as a model for dsDNA. In initial experiments, specific anti-DNA binding could not be demonstrated because of high background binding of patient Ig to PLL-treated surfaces. This was reduced by diluting test sera and anti-Ig in buffer containing 2% BGG and 1% BSA. Specificity of the assay for DNA was demonstrated by absorbing the anti-DNA activity on DNA-coated plastic. The binding of systemic lupus erythematosus (SLE) patient serum Ig to poly dA-dT coated trays did not diminish after digestion with nuclease S1, suggesting that the synthetic polymer is an appropriate model for dsDNA. Patient and normal sera were screened for anti-dsDNA activity using poly dA-dT as antigen. None of the 38 normal sera, 23 of 35 active SLE sera, 1 of 25 treated SLE, 4 of 35 rheumatoid arthritis, 3 of 35 scleroderma, and 1 of 13 polymyositis sera demonstrated positive anti-dsDNA activity. The anti-dsDNA values obtained in the radioimmunoassay correlated significantly with those obtained in the Crithidia luciliae assay.

Antibodies↗

Low molecular weight IgM in rheumatoid arthritis and other rheumatic diseases.

Low molecular weight (LMW) IgM was measured in the serum and synovial fluid of patients with rheumatoid arthritis (RA) and other rheumatic diseases. High levels were seen in RA, particularly in rheumatoid vasculitis and Felty's syndrome, and significant correlations occurred between LMW IgM and the rheumatoid factor (RF) level and other indices that reflected active or severe disease. LMW IgM-RF, measured by radioimmunoassay in those column fractions containing LMW IgM, correlated significantly with LMW IgM (P less than 0.005); preliminary experiments suggested that in some sera, a considerable proportion of the LMW IgM consisted of LMW IgM-RF. We conclude that LMW IgM and LMW IgM-RF may have important implications in the immunopathogenesis of RA and other rheumatic diseases.

Adolescent↗

Serum IgG and IgM rheumatoid factors by solid phase radioimmunoassay. A comparison between adult and juvenile rheumatoid arthritis.

In this report, solid phase radioimmunoassays that specifically measure IgG rheumatoid factor (RF) and IgM RF in absolute concentrations are described. Polyclonal RF preparations were utilized as standards, and as little as 40 ng/ml of IgG RF and I ng/ml of IgM RF were detected. The IgG RF concentration of 26 seropositive rheumatoid sera was 439 +/ 755 micrograms/ml (mean +/- 1 SD), a level 107 times that of normal controls (P less than 0.001). In contrast, levels for 49 children with juvenile rheumatoid arthritis (JRA) were 6.1 +/- 3.7 micrograms/ml for those with a polyarticular onset (JRA-Po), and 27.3 +/- 113 micrograms/ml for the pauciarticular group (JRA-Pa), and 12.6 +/- 20.7 micrograms/ml for the group with a systemic onset (JRA-S). None of these values differed significantly from the value of 6.0 +/- 3.9 micrograms/ml measured in a juvenile control group. The IgM RF level in adult rheumatoid arthritis (RA) of 175 +/- 221 micrograms/ml was also significantly elevated compared to controls (P less than 0.001). In JRA, however, mean levels of 1.4 +/- 2.0 micrograms/ml (JRA-Po), 2.8 +/- 8.3 micrograms/ml (JRA-Pa), and 1.1 +/- 0.7 micrograms /ml (JRA-S) were not elevated significantly above the value of 1.2 +/-1.2 micrograms/ml measured in the juvenile control group. Hidden IgM RF was not found in 9 JRA sera tested. These marked differences in RF levels provide another indication that adult RA and JRA are distinct diseases.

Adult↗

Prevention of glomerulonephritis and prolonged survival in New Zealand Black/New Zealand White F1 hybrid mice fed an essential fatty acid-deficient diet.

Female B/W mice spontaneously develop an autoimmune disease that is similar to systemic lupus erythematosus. Antibodies to doublestranded DNA (dsDNA) and antinuclear antibodies develop in aging animals; death from immune complex-mediated glomerulonephritis occurs from 8 to 12 mo of age. It has been reported that prostaglandin (PG)E(1) treatment of such mice prolongs survival. In the present study, four groups of female B/W mice were studied beginning at 6-11 wk of age on the following regimens: (a) a synthetic diet that contained 20% safflower oil, (b) a standard laboratory chow diet, (c) a standard diet together with injections of PGE(1), and (d) an essential fatty acid-deficient synthetic diet that contained 20% coconut oil. All animals were tested monthly for antinuclear antibodies and anti-dsDNA. Kidney tissue was obtained for light and immunofluorescence microscopy when animals were dying. All disease manifestations were altered strikingly in the essential fatty acid (EFA)-deficient animals. Intermediate benefit was seen in PGE(1)-treated animals. 7% of the control animals and 18% of safflower oil-fed animals survived to 10 mo. In contrast, the PGE(1)-treated and EFA-deficient mice had a similar survival rate (78-88%). At age 16 mo, 78% of EFA-deficient mice and 45% of PGE(1)-treated mice were alive. 25% of the PGE(1)-treated and 55% of the EFA-deficient animals survived to 20 mo. Serum anti-dsDNA appeared at age 5 mo in safflower oil-fed and control animals, but not until 9 and 12 mo for PGE(1)-treated and EFA-deficient animals, respectively. All kidneys from 7- to 9-mo-old safflower oil-fed and control animals and the majority of kidneys from PGE(1)-treated animals were abnormal by light and immunofluorescence microscopy. Kidneys from EFA-deficient animals were essentially normal at 10 mo. At 13 mo, all PGE(1)-treated animals examined had significant kidney involvement, whereas none of the EFA-deficient animals had glomerulonephritis. These findings demonstrate that an EFA-deficient diet has a beneficial effect on murine lupus erythematosus.

Age Factors↗

Defective B cell tolerance in adult (NZB X MZW)F1 mice.

Hapten-specific tolerance was induced in vitro by trinitrophenyl-human gamma globulin (TNP32HGG) to a comparable degree in B cells from adult autoimmune (NZB X NZW)F1 (B/W) mice and normal BDF1, CBA/J, and DBA/1J mice. When a lower epitope density tolerogen (TNP7HGG) was used, B/W mice were significantly less sensitive than normal mice to the induction of B cell tolerance. This finding of defective B cell tolerance in adult B/W mice is consistent with previous reports that document other B cell abnormalities that may relate to the expression of autoimmune disease.

Animals↗