Factors predicting a poor life prognosis in rheumatoid arthritis: an eight year prospective study.

This prospective study evaluates the usefulness of clinical features and measurements of circulating immune complexes and autoantibodies for identification of patients with rheumatoid arthritis with a poor life prognosis. One hundred and seven hospital clinic patients, 64 with extra-articular manifestations, were followed up for a mean period of eight years, during which 50 deaths occurred. Comparison with an age and sex matched control population showed an increased incidence of deaths from myocardial infarction, pneumonia, and complications of rheumatoid arthritis. Patients with cutaneous ulcers, vasculitic rash, neuropathy, and scleritis had a higher mortality than patients whose disease was confined to the joints. Positive serological tests for precipitating antibodies to soluble cellular antigens and cryoglobulinaemia also predicted a poor prognosis. Eleven out of 12 patients (92%) with antibodies to soluble cellular antigens died compared with 21 out of 64 patients (33%) without antibodies. The presence of cryoglobulinaemia was associated with almost a twofold higher mortality. The laboratory measurements may reflect immunopathogenic mechanisms which lead to the occurrence of extra-articular disease features and reduce life expectancy.

Reaction of antibodies to rheumatoid arthritis nuclear antigen with a synthetic peptide corresponding to part of Epstein-Barr nuclear antigen 1.

Antibodies to rheumatoid arthritis nuclear antigen (RANA) are detected by immunodiffusion (ID) and immunofluorescence (IF), though reports of the identity of the antigen(s) have been conflicting. In this study it is shown conclusively that ID and IF anti-RANA react with epitopes on Epstein-Barr nuclear antigen 1 (EBNA-1) and that the major epitope detected by immunofluorescence is represented by a synthetic peptide, P62, corresponding to part of EBNA-1. In an enzyme linked immunosorbent assay (ELISA) anti-P62 antibodies in 35 rheumatoid arthritis sera were threefold higher than those of 35 age and sex matched controls, with the highest levels occurring in young patients with active joint disease.

Autoimmunity to La (SS-B) in vitro is related to HLA-DR3 in healthy subjects.

In patients with Sjögren's syndrome 50-90% of those who have anti-La (SS-B) in their serum are HLA-DR3 positive. To investigate the relation between DR3 and anti-La antibody production 18 healthy subjects were divided into nine pairs, each matched for age and sex, containing one DR3 positive individual and one with a different DR type. Peripheral blood mononuclear cells from each pair were cultured with varying doses of pokeweed mitogen and supernatants from nine day cultures assayed for antibodies to La, nRNP/Sm, and DNA by enzyme linked immunosorbent assay (ELISA) using purified antigens. In each case peak anti-La secretion was greater in the DR3 positive subject than in the matched DR3 negative individual; in contrast, there was no consistent difference in levels of anti-DNA or anti-nRNP/Sm secretion. This specificity of enhanced autoantibody response in healthy individuals after polyclonal activation suggests that anti-La production may be under the control of genes linked to DR3.

Anti-idiotypic induced suppression of Sjögren's syndrome associated anti-La autoantibody secretion in vitro.

Peripheral blood mononuclear cells from patients with Sjögren's Syndrome spontaneously secrete autoantibodies to the La antigen when cultured in vitro. This paper reports that specific IgG autoantibody production in vitro is suppressed by pre-treatment of CD8+ enriched T cells with rabbit polyclonal antibodies to idiotypes borne by circulating autologous anti-La antibodies. Treatment of this T cell subpopulation with anti-idiotypes specific for circulating anti-La antibodies from other patients or for anti-DNA antibodies was without effect on anti-La antibody production. Similarly anti-La anti-idiotypes had no effect on the production of autoantibodies to other ribonucleoprotein antigens such as nRNP/Sm. These data show that CD8+ T cells are the main targets for anti-idiotypic control in vitro. We suggest that the relative deficit of these cells, plus a surfeit of CD4+ T cells at the site of the pathological lesion within the salivary gland permits localized production of autoantibodies. Thus, dysregulation of the idiotypic network could contribute to the pathogenesis of Sjögren's Syndrome.

Idiotypes on antibodies to the La (SS-B) antigen are restricted and associated with the antigen binding site.

Rabbit anti-idiotypic antibodies were prepared against affinity purified autoantibodies to the ribonucleoprotein La (SS-B) antigen from the sera of three unrelated patients. Each anti-idiotype recognized private idiotypes expressed only on the immunizing anti-La antibody. In each case they were conformationally dependent and related to the antigen binding site. This demonstration of immunodominant private idiotypes on human autoantibodies to ribonucleoproteins is in direct contrast to the cross-reactive idiotypes described on rheumatoid factors and autoantibodies to DNA. We discuss the possibility that anti-La antibodies, unlike anti-DNA, arise as a result of autoantigenic stimulation.

HLA antigen associations with extra-articular rheumatoid arthritis.

Seventy-seven patients with rheumatoid arthritis were investigated to examine the frequency of HLA antigens and their relationship to clinical and serological manifestations of extra-articular disease. The phenotype frequencies of DR4, DRw53, Bw62 and Cw3 were significantly increased, compared to normal controls, and there were negative associations with DR2 and DR7. The HLA antigen in strongest association with rheumatoid arthritis was DR4 (73.6%) and the relationship with DRw53 appeared to be secondary. The frequency of DR4 rose to 92% in seropositive patients with extra-articular disease manifestations whose serum contained immune complexes. A high frequency of DR4 was also seen in male patients (86%), reaching 100% in the small group of seropositive male patients with immune complexes. It is suggested that extra-articular disease represents a manifestation of severe classical rheumatoid arthritis and is not an 'overlap' syndrome. We propose that the HLA haplotype Cw3-Bw62-Dw4-DR4-DRw53 makes a greater genetic contribution to disease susceptibility in both extra-articular and male rheumatoid arthritis patients than in other subsets of RA.

In vitro immunoglobulin synthesis by lymphocytes from patients with rheumatoid arthritis. I. Effect of monocyte depletion and demonstration of an increased proportion of lymphocytes forming rosettes with mouse erythrocytes.

We have investigated B cell function in nine patients with rheumatoid arthritis (RA) compared to sex and age matched controls in a pokeweed mitogen driven system. Levels of IgG and IgM synthesized in the supernatant were measured by a competition ELISA. We have found that cultured mononuclear cells from RA patients showed a defective Ig synthesis when depleted of monocytes. In contrast RA mononuclear cells not depleted of monocytes produced substantial levels of Ig after stimulation by the mitogen. The percentages of T and B lymphocytes in the peripheral blood of RA patients were normal; however, an increased number of lymphocytes formed rosettes with mouse erythrocytes indicating an abnormality in the B cell pool. These results demonstrate defective in vitro immunoglobulin synthesis by RA lymphocytes and show the importance of monocytes in this culture system.

In vivo fate of 125I SS-B (La) injected into mice.

The fate of the radiolabelled soluble cellular antigen SS-B (La) was compared with that of other 125I-labelled proteins of known molecular weight (MW) and electrostatic charge, following i.v. injection into BALB/c mice. The plasma half-life of 125I-SS-B was 3 min, while that of 125I-bovine serum albumin (similar MW and electrostatic charge) was 270 min. 125I-heat-aggregated IgG (MW greater than 1 x 10(6)) and 125I-7S human IgG (MW 168,000) had plasma half-lives of 40 min and greater than 300 min, respectively. Liver and kidney showed preferential uptake of 125I-SS-B, followed by a rapid decrease in radioactivity. During this time low MW, trichloroacetic acid (TCA) soluble, material appeared in urine. This suggests a specific uptake mechanism followed by a catabolic phase. These studies demonstrate that normal mice remove 125I-SS-B rapidly from the circulation and then degrade it. This rapid antigen elimination may protect against the induction of potentially harmful autoantibody responses.

Quantitation and detection of isotypes of anti-SS-B antibodies by ELISA and Farr assays using affinity purified antigens. An approach to the investigation of Sjögren's syndrome and systemic lupus erythematosus.

Affinity purified SS-B was characterized as a protein with immunoreactive polypeptides of 40K and 29K. A modified Farr assay and an enzyme linked immunosorbent assay (ELISA) were 100- to 1,000-fold more sensitive than immunodiffusion and showed an association with the systemic manifestations of primary sicca syndrome and Sjögren's syndrome with systemic lupus erythematosus. The ELISA was sufficiently sensitive to detect class specific antibodies in saliva and lymphocyte culture supernatants.

Antibodies to nuclear antigens in polymyositis: relationship to autoimmune 'overlap syndromes' and carcinoma.

Thirty-two patients with polymyositis were categorised into 4 groups: (1) 'pure' polymyositis, (2) dermatomyositis, (3) myositis associated with autoimmune 'overlap syndrome', and (4) those with associated malignancy. Serum from each patient was examined for a range of antinuclear antibodies. Seventeen patients had ANA detected by immunofluorescence, 18 patients had raised DNA binding (greater than 25 U/ml), of whom eight had levels greater than 50 U/ml (SI conversion: U/l = U/ml x 10(3)). Antibodies to soluble nuclear antigens were detected in 23 (72%) by 1 or more of 3 methods, and in all of these anti-RNP was the main antibody detected. Antibodies to other soluble antigens were also present in 6 sera. In 2 cases, both patients with SLE/myositis overlap, these were shown to be anti-Sm. The remaining 4 had antibodies to various protein components of the extracts, but it was not possible to demonstrate an antibody of diagnostic specificity for polymyositis. Furthermore, quantitation of anti-RNP and anti-DNA antibodies failed to define a distinct clinical entity or exclude malignant disease. High levels of anti-RNP antibodies showed an association with Raynaud's phenomenon, sclerodactyly, and pulmonary fibrosis and an inverse correlation with the rash of dermatomyositis, suggesting that this antibody may be of pathogenetic rather than diagnostic significance.

Interpretation of the Raji cell assay in sera containing anti-nuclear antibodies and immune complexes.

The Raji cell assay is regarded as a test for the detection and quantitation of immune complexes. It is frequently positive in sera from patients with SLE. We have demonstrated a relationship between Raji cell binding and antibodies to DNA and soluble cellular antigens. In five sera containing high titres of antibodies of known single specificity, most of the Raji cell binding occurred in the 7S IgG fraction where the majority of anti-nuclear antibody was also found. When each of these sera was incubated with its specific antigen, Raji cell binding increased. Subsequent fractionation showed that this binding was in the high molecular weight fraction (greater than 200,000 daltons) and that Raji cell binding and antibody activity were abolished in the 7S fraction. These data confirm that Raji cell bind immune complexes but also indicate that 7S anti-nuclear antibodies may interact directly with Raji cells by an unknown mechanism. Therefore, in sera of patients with anti-nuclear antibodies, binding to Raji cells does not necessarily imply the presence of immune complexes alone.

The effect of IgG aggregate size and concentration on reactivity in immune complex assays.

The reactivity of heat-aggregated IgG of known size, in the Raji cell assay, the C1q binding assay and the C1q solid phase radioimmunoassay as a function of concentration, has been investigated. Marked differences were found in the way that the three assays behave when the IgG concentration and aggregate size are varied. These findings indicate the pitfalls in attempting to express the results of immune complex assays performed on biological fluids in terms of equivalent concentrations of aggregated IgG.