"Microgel diffusion blotting" for sensitive detection of antibodies to extractable nuclear antigens

A fast immunoblotting procedure, termed "microgel diffusion blotting," is used to detect and identify antibodies to extractable nuclear antigens (i.e., to Sm, RNP, and SSB) in patients with rheumatic diseases. The method differs from the standard immunoblotting techniques by the use of ultra-thin microgels for polyacrylamide gel electrophoresis: the very thin gel layer allows transfer of proteins to a nitrocellulose membrane by simple diffusion. Principal advantages of this variant technique are its simplicity, rapidity, and reproducibility--characteristics that make the test suitable for routine application. We compared the sensitivity of the test with that of double immunodiffusion in agarose for the evaluation of humoral antinuclear immunity. Microgel diffusion blotting detected antibodies in serum at concentrations less than 0.001 of those detectable by immunodiffusion.

"Microgel diffusion blotting" for sensitive detection of antibodies to extractable nuclear antigens

A fast immunoblotting procedure, termed "microgel diffusion blotting," is used to detect and identify antibodies to extractable nuclear antigens (i.e., to Sm, RNP, and SSB) in patients with rheumatic diseases. The method differs from the standard immunoblotting techniques by the use of ultra-thin microgels for polyacrylamide gel electrophoresis: the very thin gel layer allows transfer of proteins to a nitrocellulose membrane by simple diffusion. Principal advantages of this variant technique are its simplicity, rapidity, and reproducibility--characteristics that make the test suitable for routine application. We compared the sensitivity of the test with that of double immunodiffusion in agarose for the evaluation of humoral antinuclear immunity. Microgel diffusion blotting detected antibodies in serum at concentrations less than 0.001 of those detectable by immunodiffusion.

Proteoglycan metabolism in tissue-cultured human articular cartilage. Influence of niflumic acid

Proteoglycan metabolism was investigated in tissue-cultured human cartilage. Normal cartilage obtained from a normal joint showed improving accumulation rates for 35S-labelled proteoglycans over a 3-6 weeks' period. The loss of newly synthesized molecules in the nutrient media was low and constant throughout culture. A decrease in accumulation of 35S-proteoglycan was observed in visually intact cartilage from joints showing foci of osteoarthrosis. This decrease was more pronounced in fibrillated cartilage. No clear effect on proteoglycan metabolism was observed when normal cartilage samples from the normal joint were incubated for several weeks in a nutrient medium containing niflumic acid. However, the cartilage samples from this donor tended to retain more proteoglycan aggregates in the intercellular matrix after a 6-weeks culture period in the presence of this NSAID. When niflumic acid was added to the incubation media of visually intact samples from pathological joints, significantly more newly synthesized proteoglycans were retained in the intercellular matrix. The effect was also observed and was more pronounced in the fibrillated cartilage samples.

Destructive lesions of small joints in seronegative spondylarthropathies: relation to gut inflammation

Destructive lesions of small joints were found in 40 out of 211 patients suffering from seronegative spondylarthropathies (SpA) on whom ileocolonoscopy with biopsies of the ileum and colon were performed. The destructive lesions of small joints, radiologically only distinguishable from rheumatoid arthritis lesions by the pauciarticular and asymmetrical involvement, the rare tendency to fusion and the rare occurrence of periosteal hypertrophy, were observed more frequently in patients presenting subclinical inflammatory gut lesions, predominantly of the chronic type, than in patients without gut inflammation.

Subclinical involvement of the gut in undifferentiated spondylarthropathies

In order to evaluate the frequency of subclinical gut involvement in the seronegative spondylarthropathies, ileocolonoscopy with biopsies of the colon, ileocecal valve and ileum were performed on 211 patients with ankylosing spondylitis (AS), reactive arthritis (ReA) and undifferentiated spondylarthropathies. Inflammatory gut lesions were detected in a large number of these patients. It was concluded that the group of undifferentiated spondylarthropathies could be split into fairly equal subgroups: one subgroup suffering from subclinical inflammatory bowel disease associated with peripheral joint symptoms, a second subgroup presenting a form of enterogenic ReA, and a third subgroup in which no relation with the gut could be demonstrated. Ankylosing spondylitis, which has to be considered as a form of undifferentiated seronegative spondylarthropathy, could be subdivided into the same subgroups. These findings confirm the existence of subclinical gut involvement in patients with seronegative spondylarthropathies.

Proteoglycan metabolism in tissue cultured human articular cartilage. Influence of piroxicam

Proteoglycan metabolism was investigated in longterm tissue cultured human cartilage. Visually intact cartilage from adult donors showed improving accumulation rates for 35sulfate labelled proteoglycans over a 6-week period. The loss of newly synthesized molecules in the nutrient culture media was low and constant. Fibrillated cartilage from a 17-year-old male showed higher basal 35S incorporation rates and the proportions of 35S proteoglycan aggregates were higher than in normal tissue. These observations may reflect the immature status of the tissue or an attempt at repair. However samples lost increasing amounts of 35S proteoglycans in the incubation media. This material appeared to be monomeric proteoglycan. The amount of 35S activity retained in the fibrillated tissue matrix fell during culture as did the proportion of proteoglycan aggregates. Thus catabolic events were postulated in these fibrillated cartilage samples. When piroxicam was added to the incubation media more newly synthesized proteoglycans were retained in the intercellular matrix of the fibrillated samples. Increased accumulation of 35S activity was seen in some of the batches of visually intact cartilage.

Proteoglycan metabolism in isolated chondrocytes from human cartilage and in short-term tissue-cultured human articular cartilage

The effect of piroxicam on proteoglycan metabolism of human cartilage cells was investigated in two in vitro models. Cells or tissue samples were obtained from six different donors. Piroxicam levels used in the test systems ranged from 2 to 6 micrograms r/ml and were comparable with serum concentrations in humans after oral intake. Piroxicam increased the synthesis rates of proteoglycan in some batches of isolated and monolayer-cultured chondrocytes and in tissue-cultured articular cartilage. The fact that this increase in the synthesis of proteoglycan was restricted to some of the donors whereas isolated cells or tissue samples from other individuals remained unaffected illustrates the heterogeneity of different human donors. Depression of proteoglycan synthesis in the presence of the drug was not observed.

The diagnostic significance of the antiperinuclear factor for rheumatoid arthritis

Sensitivity and specificity of antiperinuclear factor (APF) determination were assessed in 127 patients with classical or definite rheumatoid arthritis (RA). The control population consisted of 262 patients with rheumatic complaints other than RA. Our results showed a sensitivity of 86.6%, a specificity of 96.2% and a Youden index of 82.8% for APF in RA. In 14.2% of the total population with RA the rheumatoid factor (RF) became negative in the course of the disease; all but one were found to be actually APF positive. Of the population with RA analyzed, 8.6% were consistently RF negative but APF positive. In view of its strong sensitivity and specificity for RA, APF determination is a valuable serological tool for the diagnosis of the disease. In APF positive, RF negative patients with RA the prognosis seems to be poor.

Ileocolonoscopic findings in seronegative spondylarthropathies

Ileocolonoscopy with biopsy of caecum, ileocaecal valve and terminal ileum were performed on 232 patients with seronegative spondylarthropathies and on 65 control patients. Inflammatory gut lesions were found in 65% of the patients with reactive arthritis (ReA) and in 57% of the patients with ankylosing spondylitis (AS), especially in those with peripheral arthritis. The controls had a normal gut. This finding would suggest that exogenous factors causing inflammation of the gut lead to a disturbed permeability of the gut wall or to a deficient local immunological defence mechanism permitting antigens to enter the circulation, inducing the joint and tendon inflammation. Support for this hypothesis was provided by the results of a repeat ileocolonoscopy, disclosing a strong association between the presence of gut inflammation on biopsy and the persistence of joint inflammation. Patients presenting some of the histological lesions found on biopsy (especially active chronic lesions) and patients with proven Crohn's disease were found to share a genetic marker (HLA-BW62). This would suggest that some of the patients with seronegative spondylarthropathies suffer from a subclinical form of Crohn's disease of which the joint symptoms are the unique clinical manifestation.

Interferon gamma in rheumatoid arthritis--a double blind study comparing human recombinant interferon gamma with placebo

A double blind trial comparing recominant interferon gamma (IFN gamma) with placebo in rheumatoid arthritis is presented. Twenty-six patients entered the study and 22 completed the 6-month period. IFN gamma was administered subcutaneously as was placebo; the 1st week, patients treated with the active compound received a daily subcutaneous injection of 100 micrograms of IFN gamma and for the following 23 weeks the schedule was decreased to 2 injections of 100 micrograms every week. No serious side effects were observed. After Week 24 the group treated with the active compound showed a significant decrease of the joint tenderness score and the placebo group showed a significant increase of the number of subcutaneous nodules. All other variables shifted in favour of the active compound but not significantly. More double blind trials with a larger number of patients and using other treatment schedules or other routes of administration are required.

Thymic hormones and interferons in the treatment of rheumatoid arthritis

Interferon gamma (IFN-gamma) is known to increase the rate of biosynthesis and membrane density of Ia in cells that have normal basal expression of Ia such as Ia+-monocytes and thymic epithelium. IFN-gamma also induces de novo expression of Ia in other cell types such as Ia- macrophages, vascular endothelium, fibroblasts, a.o. Consequently, IFN-gamma enhances the activation of specific T-helper cells and the immunity that is dependent on T-helper cells. If the antigen is a viral product expressed on the membrane of an infected cell, IFN-gamma inducing an aberrant Ia expression, will produce a T-helper cell activation from which the host will benefit. If the antigen presented by the newly Ia+ cell is an autologous cell membrane molecule, one that is unique to a particular tissue and of which the host T-helper cells are not tolerant, IFN-gamma can trigger an autoimmune attack. Several recent reports have described a decreased level and activity of IFN-gamma in the rheumatoid joint environment, in vitro as well as in vivo. It is still unknown whether these findings are due to a defective production or to a physiological down regulation of IFN-gamma in rheumatoid arthritis (RA). Consequently it is not clear whether the pharmacologic administration of IFN-gamma to RA patients would reduce the disease activity or induce a disease exacerbation. Initially, short term assays were performed with daily subcutaneous injections of IFN-gamma (50 micrograms or 100 micrograms). As some encouraging results were obtained, two double-blind long-term studies were started.(ABSTRACT TRUNCATED AT 250 WORDS)

Disease manifestations of progressive systemic sclerosis: sensitivity and specificity

The authors conducted a study of 47 patients with a diagnosis of systemic sclerosis in order to determine the sensitivity, specificity and Youden index and consequently the diagnostic value of the generally accepted criteria and of some other common disease features. The control population consisted of 324 patients with rheumatoid arthritis and 35 patients with systemic lupus erythematosus. In addition to proximal scleroderma, the presence of which was required for inclusion in this study, other disease features score a high to moderate Youden index: sclerodactyly, Raynaud's phenomenon, appearance of perioral grooves, cinematographic evidence of esophageal hypomotility, periarticular calcifications, widening of the periodontal membrane on teeth radiographs and specific histologic changes on fingertip biopsy. Finally, a good correlation was found with most of the ARA subcommittee criteria.

Pigmented villonodular synovitis of the hip--association with osteochondromatosis

Pigmented villonodular synovitis, diffuse or nodular in nature, is most commonly seen in the knee but occasionally involves the hip. The authors reviewed the medical records of seven patients with a pathological diagnosis of unilateral pigmented villonodular synovitis of the hip. Characteristic findings were proliferation of the synovial lining cells and subsynovial invasion of fibroblast or polyhedral mesenchymal cells in a nodular pattern. Multiple initiating factors have been advanced to account for the occurrence of this monoarticular chronic arthritis, but the etiology and pathogenesis still remain obscure. On three occasions the authors found an association with free floating osteochondromas and well-delineated foci of metaplastic cartilage under the synovial lining cells. Two benign lesions may occur simultaneously and are possibly related entities involving the synovial membranes as a reaction to a common etiologic factor. Although the histopathology of pigmented villonodular synovitis of the hip and the knee is identical, localization in the former joint has its typical clinical, radiological, differential diagnostic and therapeutic aspects.

Late onset pauciarticular juvenile chronic arthritis: relation to gut inflammation

Ileocolonoscopy with biopsy of the ileum, ileocecal valve and cecum was performed on 32 patients (22 males, 10 females) with juvenile chronic arthritis (JCA) with pauciarticular onset. Mean age at onset of disease was 12 years. Ankylosing spondylitis (AS) was diagnosed in 13 patients; the other 19 cases were classified as reactive arthritis with recurrent or persistent pauciarticular synovitis. Twenty-two patients (68%) were HLA-B27 positive; 8 patients (25%) carried the HLA-Bw62 antigen. Ileocolonoscopy was performed 6 months to 32 years after the initial manifestation of the disease (mean : 9 years). Fourteen patients had macroscopic lesions of the ileum and ileocecal valve although only 8 of these had a history of intestinal complaints. Twenty-six patients (81%) presented histological signs of gut inflammation. Most of the gut abnormalities were classified as active chronic or Crohn-like lesions (19/26). Only 7 patients had acute or bacterial enteritis-like lesions. Acute lesions were seen in only one patient with AS. All but 2 patients with sacroiliitis, in whom signs of gut inflammation were found, had active chronic lesions. All the 8 HLA-Bw62 positive patients had histological evidence of gut inflammation. Only chronic or Crohn-like lesions were found. In the majority of patients with JCA with pauciarticular onset, gut inflammation was found on ileum biopsy. Some of their lesions are related to Crohn's disease, and the presence of the HLA-Bw62 antigen could predispose to the arthritis seen in these cases.

HLA antigens in seronegative spondylarthropathies. Reactive arthritis and arthritis in ankylosing spondylitis: relation to gut inflammation

The prevalence of HLA-A, B, C and DR antigens was determined and compared in 94 patients with reactive arthritis, 54 patients with ankylosing spondylitis (AS), 37 patients with inflammatory bowel disease (IBD) and in 1,010 apparently normal blood donors. The 185 patients all underwent ileocolonoscopy with biopsy of ileum, ileocecal valve and cecum. HLA-B27 was found elevated in the groups with reactive arthritis (48%, chi 2 = 82, p less than 0.0005) and the AS groups (78%, chi 2 = 157, p less than 0.0005), compared to healthy controls. HLA-Bw62 was significantly raised in the patients with reactive arthritis (34%, chi 2 = 73, p less than 0.0005) (particularly the HLA-B27 negatives (48%, chi 2 = 90, p less than 0.0005) and in the HLA-B27 negative patients with AS (25%, chi 2 = 5.5, p less than 0.02). This did not apply to the other patients with AS (4.7% NS). HLA-Bw62 could be associated with a specific clinical picture of asymmetrical pauciarticular arthritis, accompanied by enthesopathies and sacroiliitis classified as idiopathic reactive arthritis, especially when the disease is of enterogenic origin. The frequency of HLA-Bw62 was very high in patients with reactive arthritis and in patients with AS with active chronic (n = 39, 23%, chi 2 = 13, p less than 0.0005) and Crohn-like lesions (n = 14, 50%, chi 2 = 35, p less than 0.0005) on gut biopsy, normal in patients with acute lesions (n = 35, 11%, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Repeat ileocolonoscopy in reactive arthritis

Ileocolonoscopy on patients with HLA-B27 related disease, reactive arthritis and ankylosing spondylitis (AS) with peripheral arthritis, revealed the presence of inflammatory lesions in biopsy specimens from the ileum in 71 and 60% of the cases, respectively. A 2nd ileocolonoscopy was performed on 14 patients, 4 to 22 months after the first. In 6 of the 7 patients in articular clinical remission, the inflammatory gut lesions had disappeared. The gut biopsies of the 7 patients with active joint disease continued to show inflammatory lesions. One of these patients underwent a 3rd ileocolonoscopy after having gone into clinical remission, possibly secondary to treatment with sulfasalazine; the histology was completely normal. The strong relationship between clinical articular inflammation and gut inflammation seems to support the hypothesis that in B27 related diseases, repetitive exogenous triggering causing transgression of oral tolerance by increased gut permeability, provokes and maintains the joint inflammation.

In vitro repair potential of articular cartilage: proteoglycan metabolism in the different areas of the femoral condyles in human cartilage explants

We tested the hypothesis that metabolism of individual cartilage samples, such as those which might be taken at arthroscopy, could reflect the overall intrinsic reparative response of the cartilaginous tissue of that joint. Full thickness samples of articular cartilage, removed from the anteromedial, anterolateral and posterolateral areas of the femoral condyles of 2 normal knees, were placed in tissue culture separately. The incorporation of 14C-glucosamine into matrix molecules, especially proteoglycan, was measured. Three slices of each area were removed after one, 3 or 6 weeks of in vitro culture. The extracted matrix molecules and the media were analyzed and the relative amount of radioactive proteoglycan and proteoglycan aggregates, as well as the total amount of radiolabelled proteoglycan/mg dry weight, were calculated. A progressive increase in these variables during the culture period was demonstrated, suggesting an attempt at repair of the articular cartilage in this in vitro condition. No differences in the incorporation dynamics were found between the anteromedial, anterolateral and posterolateral areas of both subjects.

Reparative response of human articular cartilage in tissue culture. Comparison between a normal and an osteoarthritic knee of the same donor

Some evidence is presented that the metabolism of visually intact cartilage taken from a knee with focal osteoarthritic lesions, may already be affected. Proteoglycan metabolism of articular cartilage from the macroscopically unaffected right knee and the osteoarthritic left knee of the same donor was assayed in long-term tissue culture. A good reparative response was found in the right knee with an increase in the relative amount of radiolabelled proteoglycan and proteoglycan aggregates, and in the total amount of labelled proteoglycan per mg dry tissue. No significant differences were found when the anteromedial, anterolateral and posterolateral areas were compared. Visually intact samples taken from the left knee, with a deep osteoarthritic cartilage erosion on the medial condyle, showed no accumulation of radiolabel into proteoglycan and proteoglycan aggregates for the enzymatically pretreated samples. This was interpreted as a repair failure.