Virus antibodies in serum and synovial fluid of patients with rheumatoid arthritis and other connective tissue diseases.
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Rubella and influenza A (H3N2) haemagglutination inhibition (HI) antibody titres and measles complement-fixing (CF), haemagglutination inhibition (HI), haemolysis inhibition (HLI), and ribonucleoprotein gel precipitation (RNP-GP) antibody titres were studied in the serum and synovial fluid of twenty patients with rheumatoid arthritis (RA), two patients with ankylosing spondylitis, and two patients with Reiter's syndrome. Antibody titres were also studied in the serum and CSF of four patients with systemic lupus erythematosus (SLE), one patient with dermatomyositis, and in the synovial fluid only of five patients with osteoarthritic knee effusions. Antibodies were found with each serological technique used in the synovial fluid of RA patients and the antibody titres were usually at about the same level as in the serum. The mean measles (HI, HLI, and RNP-GP) antibody titres were 4 to 6 times higher in the synovial fluid of RA patients than in synovial fluid of patients with osteoarthritic knee effusions, but a corresponding difference was not found in rubella and influenza A antibody titres. The mean measles antibody titres (CF, HI, HKI, and RNP-GP) were consistently higher in the synovial fluid of RA patients without rheumatoid factor than in the synovial fluid of RA patients with rheumatoid factor. In serum this difference was observed only with measles CF titres. The mean measles, antibody titres were consistently lower in the serum and synovial fluid of the RA patients without the synovial fluid haemolytic complement than in the RA patients with this haemolytic complement. No similar differences were found in the rubella and influenza antibody titres. No significant measles antibody titres were found in the CSF of patients with SLE or dermatomyositis. (+info)
Differential requirements for induction of total immunoglobulin and physiological rheumatoid factor production by human peripheral blood B cells.
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Rheumatoid factors (RFs) are autoantibodies directed against the Fc part of IgG. Considerable evidence exists that there are two classes of RFs, pathological and physiological. Whereas pathological RFs are associated with disease, physiological RFs are considered to be a normal component of the immune response. RF(+) precursor B cells present as part of the B cell repertoire of healthy individuals are held responsible for the production of physiological RFs, which is a transient phenomenon with a clear correlation with an initiating stimulus such as immunization or exposure to an infection. Here we demonstrate a difference in the regulatory control of total Ig and RF production by peripheral blood (PB) B cells of both healthy controls (HC) and patients with rheumatoid arthritis (RA). Highly purified B cells from HC and patients with RA were cocultured with T cells stimulated with immobilized anti-CD3 mAb. Similar to IgM production, IgM-RF production was shown to be dependent on CD40 cross-linking. However, activation of PB B cells in the CD40 system in the presence of IL-2, IL-4, IL-10, combinations of these cytokines or supernatant of anti-CD3-stimulated T cells failed to induce detectable IgM-RF, whereas total IgM production was considerable. From these results we conclude that conditions to activate physiological RF(+) B cells require additional contact besides CD40--CD40L interactions between T and B cells. Since the requirements for RF production were similar using PB B cells from HC and patients with RA it is suggested that the regulatory properties of RF(+) precursors in the PB B cell compartment is equal among these groups. Together, these results indicate that conditions for the induction of total Ig and physiological RFs are different. (+info)
Prevalence and clinical significance of antikeratin antibodies and other serological markers in Lithuanian patients with rheumatoid arthritis.
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OBJECTIVES: To assess the clinical value of several serological markers in Lithuanian patients with rheumatoid arthritis (RA) compared with control patients with rheumatic disease and age matched healthy controls. METHODS: Serum samples from 96 patients with RA of approximately 8 years' duration, 90 rheumatic disease controls, and 37 healthy subjects were tested. Antikeratin antibody (AKA), antineutrophil cytoplasmic antibody (ANCA), and antinuclear antibody (ANA) titres were estimated by indirect immunofluorescence (IIF) and serum samples positive for ANA and ANCA were further studied by enzyme linked immunosorbent assay (ELISA). IgA and IgM rheumatoid factors (RF) were measured by ELISA. RESULTS: A positive AKA test was highly specific for RA (diagnostic specificity 97%), being found in 44% of the patients. Although both RF tests had a higher sensitivity, they were less specific for RA. ANCA was detected in 33% of patients with RA but lacked diagnostic specificity. AKA and ANCA were associated with more erosive disease and the presence of extra-articular manifestations. Positivity for AKA, IgA RF, and ANCA was significantly associated with disease activity and worse functional capacity. However, in multiple regression analysis only positivity for AKA was significantly correlated with functional disability (p=0.0001), evaluated by the Steinbrocker functional classification, and no single marker had any relation with radiological damage. CONCLUSION: Although AKA showed the highest disease specificity, all serological markers studied except ANA exhibited interesting associations with important clinical and paraclinical parameters of RA. (+info)
Clinical and immunogenetic characteristics of European multicase rheumatoid arthritis families.
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OBJECTIVE: To describe the characteristics of a new set of European families with affected sib pairs (ASP) collected by the European Consortium on Rheumatoid Arthritis Families (ECRAF) to replicate the results of our first genome scan. Potential gradients for disease severity in Europe and concordance within families were studied. PATIENTS AND METHODS: From 1996 to 1998 European white families with at least two affected siblings were enrolled in the study. Demographic (sex, age at onset), clinical data (rheumatoid factor (RF), disease duration, erosive disease, extra-articular features (EF)), and HLA-DRB1 oligotyping were analysed. RESULTS: 565 patients with rheumatoid arthritis (RA), belonging to 271 families including 319 affected sib pairs (ASP) were collected. Belgium, France, Italy, the Netherlands, Portugal, and Spain contributed 20, 96, 52, 24, 9, and 70 families, respectively. Sex (78% women), age at onset (mean 44 years), and RF positivity (79%) were similar among the countries. Differences were found in disease duration (11-18 years) and in the prevalence of erosive disease (70-93%), nodules (15-44%), subjective Sjogren's syndrome (5-38%), and EF (3-16%) (p<0.05 in all cases). A total of 22% RA sibs were shared epitope (SE) negative, whereas 47% and 30% carried one and two SE alleles respectively. Carriage of SE differed widely among countries (p<0.0001): no SE alleles (6-36%), one allele (43-60%), and two alleles (20-39%). SE encoding alleles were mainly DRB1*04 in the Netherlands and Belgium, whereas SE carriage was less common and evenly distributed between DRB1*01, *04, and *10 in Mediterranean countries. No concordance within families was found either in age/calendar year of onset (intraclass correlation coefficient <0.50) or in clinical and radiological features (kappa<0.22). CONCLUSIONS: The differences in RA characteristics between European countries and within families underline the heterogeneity of the disease. No clear cut gradient of disease severity was seen in Europe. (+info)
Joint swelling as a predictor of death from cardiovascular disease in a population study of Pima Indians.
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OBJECTIVE: Markers of inflammation have recently been shown to be predictive of cardiovascular disease (CVD). Furthermore, the excess mortality in rheumatoid arthritis (RA), a disease characterized by chronic polyarthritis, is chiefly due to death from CVD. With this background, we studied the effect of inflammation, as reflected by the number of joints with soft tissue swelling, and rheumatoid factor (RF) seropositivity on CVD-related mortality. METHODS: Mortality rates and rate ratios for all-cause and CVD-related deaths were computed in a longitudinal, population-based cohort of Pima Indians in Arizona from 1965 through 1994. Repeated health examinations were performed, involving systematic assessment of the features of RA, cardiovascular risk factors, serum titers of RF, as well as mortality. The cohort comprised 4,120 subjects (1,861 men, 2,259 women) who were examined an average of 3.5 times during a mean followup of 14 years. RESULTS: During the followup period, 182 CVD-related deaths ocurred. The age- and sex-adjusted CVD-related mortality rates increased significantly with the presence of a higher number of joints with soft tissue swelling (Ptrend = 0.04), and were 2.07 (95% confidence interval [95% CI] 1.30-3.31) times as high in those subjects who had 2 or more swollen joints as in those who had none. There were no significant additional effects on CVD-related mortality when seropositivity for RF or a previous diagnosis of RA were considered. In age- and sex-adjusted proportional hazards analyses, which were controlled for possible confounders, the effect of swollen joints remained significant (mortality rate ratio 1.33, 95% CI 1.04-1.71 per category increase [no swollen joints, 1 swollen joint, at least 2 swollen joints]). CONCLUSION: Joint swelling is a significant risk factor for CVD-related death, independent of other known risk factors including a diagnosis of RA. This finding supports the hypothesis that inflammatory mechanisms are important for the development of CVD. (+info)
Rheumatoid arthritis in an urban South African Negro population.
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(1) An epidemiological study of an urban South African Negro community has been carried out in Johannesburg. Altogether 964 respondents were examined and in each case radiographs of the hands and feet were obtained. Rheumatoid factor tests were carried out on 404 serum samples. (2) Rheumatoid arthritis (RA) was graded 'definite' or 'probable' on the basis of a modification of the Rome criteria (Kellgren, Jeffrey, and Ball, 1963a). (3) In marked contrast to the findings in rural Africans the prevalence of RA in this community was similar to that in Caucasian populations. Five respondents (all elderly women) had 'definite' RA, giving a prevalence of 1.4% of the females and 0.9% of the total population sample over 15 years old. The prevalence of 'definite' and 'probable' RA combined was 2.6% for males, 3.7% for females, and 3.3% for all individuals over 15 years old. Prevalence increased with age, reaching a maximum in the 65- to 74-year cohort. (4) The form and severity of the clinical and radiological features were unlike the mild manifestations seen in rural African peoples and closely resembled the usual clinical picture of rheumatoid disease. (5) The latex fixation test was positive in 12.1% of the sera tested, which is similar to the high titres found in other African populations. No obvious cause for this phenomenon was found. (6) Several reasons for the marked difference in prevalence of RA between this urban African population and a rural African population are considered. Marked intraracial differences such as this point to the importance of sociological and environmental factors in the pathogenesis of rheumatoid arthritis. (+info)
Rheumatoid arthritis in a rural South African Negro population.
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(1) An epidemiological study of a rural African community has been carried out in the Western Transvaal. Altogether 801 respondents over 15 years old were examined; radiographs of the hands and feet were obtained in all these individuals. Serological tests for rheumatoid factor were carried out on 516 blood samples. (2) The diagnosis of inflammatory polyarthritis was based on a modification of the Rome Criteria of 1961. Two categories were defined: 'definite' and 'probable' rheumatoid arthritis. (3) In this population inflammatory polyarthritis was much less common and much milder in its manifestations than in European and American peoples. The prevalence of 'definite' rheumatoid arthritis was 0.12% and of 'definite' and 'probable' rheumatoid arthritis combined, 0.87. Such changes as were encountered on clinical and radiological examination were invariably mild; no respondent in the entire survey had clinical features that would have been accepted in the ordinary way as those of rheumatoid arthritis. (4) The latex fixation test (LFT) was positive in 8.9% of the sera tested; the modified LFT aftaer inactivation of the serum at 56 degrees C was positive in 15.1% of cases. Similar findings in West African populations have been explained on the basis of alteration of the immune response by widespread parasitic infections. No obvious aetiological factor of this type was found in the present survey. (+info)
Diagnostic accuracy of the anti-citrulline antibody assay for rheumatoid arthritis.
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BACKGROUND: Rheumatoid arthritis (RA) is the most common autoimmune rheumatic disease, but specific and practicable tests for its diagnosis are lacking. We evaluated the diagnostic accuracy of a new commercial ELISA in detecting anti-cyclic citrullinated peptide (CCP) antibodies for the diagnosis of RA. METHODS: Anti-CCP antibodies were determined in 330 serum samples: 98 from RA patients and 232 from controls, including patients with connective tissue diseases, other rheumatic diseases, viral infections, Lyme disease, autoimmune thyroiditis, cancer, and monoclonal gammopathy, and sex- and age-matched healthy subjects. Intra- and interassay CVs were 5-13% and 9-17%, respectively. Rheumatoid factor (RF) was also assayed in every sample, and results were compared to anti-CCP for sensitivity and specificity. RESULTS: At a cutoff value of 50 units, sensitivity was 41% (confidence interval, 31-50%) and specificity was 97.8% (95-100%). Anti-CCP-positive RA patients had a mean antibody concentration of 1100 units (range, 57-3419 units), and anti-CCP-negative RA patients and controls had mean values of 7.6 and 6.8 units, respectively (range, 1-39 units). The area under the ROC curve was 0.71 (95% confidence interval, 0.63-0.78). RF had a higher sensitivity (62%) and a lower specificity (84%) than anti-CCP. When the two antibodies were used together, specificity was 99.6%. CONCLUSION: Anti-CCP antibody testing may be useful if performed concomitantly with RF assay to diagnose patients with suspected early RA. (+info)