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Results for “Rheumatoid Factor”

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At least 19 recordsLinked to original sources
PubMed1978

The clinical and pathogenetic significance of rheumatoid factors.

Rheumatoid factors are immunoglobulins with antibody specificity for antigenic sites on the Fc part of the heavy chain of IgG. The heterogeneity of RF in terms of antigenic specificity and class of immunoglobulin is indicative of the complexity of the provoking immune response. There is little doubt that in many patients rheumatoid factors are autoantibodies which form part of immune complexes, and that complexes containing IgG rheumatoid factor appear to be of pathogenetic importance. Although IgM rheumatoid factors are not specific for RA, their detection aids in the diagnosis and categorisation of rheumatoid arthritis. On the other hand, IgG rheumatoid factors occur in a variety of rheumatic diseases and are of little diagnostic value.

Adult↗
PubMed1979

Performance of latex-fixation kits used for serologic diagnosis of rheumatoid factor in rheumatoid arthritis sera.

Ten latex-fixation kits (both slide and tube) were evaluated by use of a reference serum containing 250 IU of rheumatoid factor (Communicable Disease Center). All tests were performed with serial dilution of serum; adjacent tubes differed by a factor of 0.10 log10. Geometric titers, means, standard deviations, and variance analysis were used to evaluate commercial kits. Three levels of variance were applied: (1) 0.18 or less for intralaboratory variation when the same serum is tested with the same kit; (2) 0.18-0.35 when various lots or batches of the same serum were used; (3) 1.0 or less when various commercial kits were tested with the same serum. The sensitivity of each commercial kit was determined by assigning to it a value (the minimum detectable unit) arrived at by dividing the number of units in the standard by the titer obtained. The technic presented could be applicable to other serologic tests, and thus provide a general method for their standardization and quality control.

Arthritis, Rheumatoid↗
PubMedDate not supplied

Relative reactivities of rheumatoid factors in serum and cells. Evidence for a selective deficiency in serum rheumatoid factor.

Investigations of rheumatoid factors by a hemolytic plaque forming cell assay of blood lymphocytes with sensitized sheep cells have suggested that the rheumatoid factors released from the cells have higher affinities for human IgG than do the rheumatoid factors measured in the patient's serum. This study reaffirms this observation and provides evidence that the reported differences are not artifacts of technique. The findings imply that rheumatoid factors of higher affinity for IgG than those of the serum are being released into the tissue fluids by lymphocytes and locally precipitated. Such rheumatoid factors may never reach the peripheral blood serum in detectable quantity or may do so only infrequently.

Animals↗
PubMed1979

IgG rheumatoid factor. Relationship to seropositive rheumatoid arthritis and absence in seronegative disorders.

IgG rheumatoid factor was detected in the sera of the majority of patients with seropositive rheumatoid arthritis. Values suggestive of IgG rheumatoid factor were noted in one-quarter of patients with seronegative inflammatory arthropathies. These determinations were always low and correlated with elevated IgG concentrations, suggesting nonspecific adherence of IgG rather than a true antigen-antibody reaction. In support of this conclusion, nonrheumatoid factor IgG was capable of concentration-dependent nonspecific adsorption to the solid phase. IgG, but not IgM, rheumatoid factor corresponded with disease activity in patients with seropositive rheumatoid arthritis, suggesting that IgG rheumatoid factor may be important in the pathogenesis.

Arthritis, Juvenile↗
PubMed1977

Rheumatoid factor in non-rheumatoid black patients.

A total of 301 Black patients without rheumatic diseases was studied to estimate the prevalence and causes of positive rheumatoid factor. The latex slide test was positive in 25% of patients and 21% had a 'diagnostic' titre of 80 or more. A significant relationship between gamma-globulin levels and rheumatoid factor positivity was demonstrated. IgG appeared to be the most important in determining this relationship. The most common ailments among sero-positive patients were cirrhosis and tuberculosis.

Adolescent↗
PubMed1977

The effect of fenoprofen calcium (Nalfon) on levels of rheumatoid factor in patients with rheumatoid arthritis.

In 88.9% of a group of 18 patients with rheumatoid arthritis participating in an open-label study with fenoprofen calcium (Nalfon), there was observed a mean titre decrease in level of rheumatoid factor as compared to baseline levels. In follow-up, three months to one year later, a uniform titre increase above the mean level of the study period had occurred. In all cases the titre returned to baseline levels or higher.

Arthritis, Rheumatoid↗
PubMed1979

Quantitation of rheumatoid factor activity by nephelometry.

Rheumatoid factor activity can be quantitated by use of nephelometric assay system. The data presented show a good correlation between this new method and the older quantitative latex tube rheumatoid factor test. In addition, the nephelometric and latex tube testing of sera from normal, rheumatoid and non-rheumatoid patients yielded similar results, suggesting the two procedures share a similar immunologic specificity. The new nephelometric test for rheumatoid factor is simple to perform, endpoints are objectively determined, and test data are highly reproducible.

Colorimetry↗
PubMed1977

Rheumatoid factor plaque-forming cells in rheumatoid synovial tissue.

Cells producing rheumatoid factor (RF) were readily detected in vitro by means of a haemolytic plaque assay system employing sheep erythrocytes (SRBC) sensitized with reduced and alkylated rabbit IgG anti-SRBC antibody as target cells. Rheumatoid factor-producing, plaque-forming cells (RF-PFC) were observed in all of the synovial tissue cell preparations from seropositive rheumatoid arthritis patients studied. The numbers of RF-PFC varied considerably without any direct correlation with serum titres of RF antibody activity. However, high numbers of RF-PFC were never found in patients with low rheumatoid factor titres whereas, high and low numbers of RF-PFC were found among the patients with high RF titres. Synovial tissue cell preparations from a group of seronegative patients, with only one exception, failed to exhibit RF-PFC.

Adolescent↗
PubMed1979

IgG-, IgM- and IgA-rheumatoid factors in healthy adults and rheumatoid patients determined by an indirect immunofluorescence method.

Sera from 173 healthy adults and 55 rheumatoid patients were studied for IgG-, IgM- and IgA-rheumatoid factors (RFs) by a modification of Este's indirect immunofluorescence method. Rabbit IgG bound to smeared sheep red cells was used as antigen. With each serum tested a smear on non-sensitized cells was used as control antigen. Anti-IgG of the sera studied, binding to the antigen, was demonstrated by fluorescein-conjugated antisera, monospecific for gamma, mu and alpha chains, and not containing antibodies to sheep erythrocytes or rabbit IgG. Positive reactions were obtained with IgG as antigen, but not with the F(ab')2 fragment. The sera tested were treated with dithiothreitol before they were assayed for IgG-RF, in order to abolish false-positive reactions due to IgM-RF activity. The detection limit for IgM-RF was 1 IU per ml. IgM-RF titres of 9 occurred in 7% of healthy adults and 73% of rheumatoid patients, titres greater than or equal to 18 in 3.5% and 67% respectively. IgG-RF titres of 9 occurred in 9% of healthy adults, 21% of seronegative and 24% of seropositive rheumatoid patients. Titres of 18 occurred in 3% of healthy adults and in 14% of seronegative rheumatoid patients. Titres of greater than or equal to 18 occurred in 22% of seropositive rheumatoid patients. IgG-RF was correlated with an involvement of more than 20 joints. IgA-RF was found in 83% of seropositive, 11% of seronegative rheumatoid patients and in none of the healthy adults (serum dilution 1:9).

Adult↗
PubMed1976

[Rheumatoid factor in systemic lupus erythematosus].

1. Rheumatoid factors were found in 12 of a total of 105 SLE patients. 2. Rheumatoid factors were found especially in patients with additional chronic polyarthritis, whereas it was not possible to find a relation between these factors and the age of patients and the duration of disease, respectively. 3. There was no difference between SLE and progressive polyarthritis as regrads the cold precipitation of rheumatoid factors. 4. In vitro fixation of the complement to antinuclear factors was not hindered by rheumatoid factors. 5. Renal lesions and uremia were observed in SLE patients with and without rheumatoid factors, the percentages being roughly the same in the two groups.

Adolescent↗
PubMed1978

[Modifications in alpha 2 globulins, gamma globulins and in rheumatoid factor during gold salt therapy in rheumatoid arthritis].

A total dose of g 1.071, given as hydrosoluble salts for a 12 month period, showed a significant decrease in serum gamma globulins along with clinical improvement in 17 patients affected with rheumatoid arthritis. A decrease in alpha 2 globulins and in rheumatoid factor titre was observed too, but it was not significant. The data suggest that in rheumatoid arthritis the gold therapy might also be effective on the immunological disease mechanism.

Adult↗
PubMed1977

Radioimmunoassay of IgG and IgM rheumatoid factors reacting with human IgG.

Although IgG rheumatoid factor may play a central role in the pathogenesis of rheumatoid arthritis, previously there have been no precise methods for its specific measurement in serum and synovial fluid. This paper describes a solid phase radioimmunoassay for the independent quantification of IgM and IgG rheumatoid factor reacting with the Fc fragment of human IgG. As measured by this assay, serum IgG rheumatoid factor levels differed significantly between patients with seropositive and seronegative rheumatoid arthritis and normal control subjects. In addition, several sera and joint fluids from patients with seropositive rheumatoid arthritis, even without vasculitis, were shown by gel chromatography to have acid-dissociable complexes of IgG rheumatoid factor suggestive of IgG-IgG dimer or trimer formation.

Alkylation↗