The clinical associations of antinuclear antibodies in juvenile rheumatoid arthritis

Clinical features of children with juvenile idiopathic arthritis using the ILAR classification criteria: a community-based cohort study in Taiwan

BACKGROUND/PURPOSE

The aim of the study was to describe the clinical features of children affected by juvenile idiopathic arthritis (JIA) under the International League of Associations for Rheumatology-derived classification criteria in a community-based setting.

METHODS

Consecutive cases of JIA from defined geographic areas of Taiwan were diagnosed and followed in an observational cohort from 1995 to 2010. In addition to the clinical and laboratory data required for the International League of Associations for Rheumatology system, information about the medication and disease activity during the study period was also recorded.

RESULTS

Out of 292 children with chronic joint pain, 195 were diagnosed as JIA: systemic arthritis (19%), oligoarthritis (persistent 16.4%; extended 6.7%), polyarthritis rheumatoid factor-negative (11.8%), polyarthritis rheumatoid factor-positive (4.6%), psoriatic arthritis (1.5%), enthesitis-related arthritis (ERA; 37.4%), and undifferentiated arthritis (2.6%). Human leukocyte antigen-B27 was positive in 82.2% of patients with ERA. Uveitis was observed in 6.7% of patients. Disease-modifying anti-rheumatic drugs, including biologic medications, were used in 73.3% of children during the observational period. At the last follow-up, 40% of patients experienced a continuously active or relapsing course.

CONCLUSION

Compared with previous reports on Western populations, a remarkably high prevalence was found in the ERA of the Chinese cohort, but a relatively low rate of uveitis. Ongoing disease activity was evident in a substantial number of children. These results provided a good starting point in understanding the epidemiology of this serious disease in the Chinese population.

Antinuclear antibodies and bromoxynil exposure in a rural sample

Previous research suggests that farmers may have an increased risk of developing autoimmunity and that exposure to certain pesticides may alter immune function. Little is known, however, about the immunologic effects of farming and pesticide exposures. As part of the Prairie Ecosystem Study, associations between detection of antinuclear antibodies (ANA), an autoimmunity indicator, and exposure to the herbicide bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) were investigated in a cross-sectional study of 208 residents (94 women, 114 men) of a cereal-producing region in Saskatchewan, Canada, during spring herbicide application, 1996. The ANA were assayed in serum by indirect immunofluorescence on HEp-2 cells. Bromoxynil was measured in plasma by gas chromatography/mass spectrometry analysis. Associations were explored between ANA detection and detection of bromoxynil in plasma, self-reported use of bromoxynil and other pesticides, farming exposures, gender, age, body mass index (BMI), and residency. The mean age (SD) of the participants was 50.8 (13.6) yr [women: 49.7 (13.5) yr, men: 51.6 (13.6) yr]. ANA prevalence was 37.5% (women: 39.4%, men: 36%,) at 1:40 serum dilution, 17.3% (women: 20.2%, men: 14.9%) at 1:80, and 10.1% (women: 13.8%, men: 7%) at 1:160. In the multiple-variable Generalized Estimating Equation (GEE) logistic regression analyses, female gender was a positive predictor of ANA detection and gender differences were observed in the relative importance of other study factors. None of the variables examined in the multiple-variable GEE analysis were statistically significant predictors of ANA detection for women. For many of these variables, however, the point estimates for women are similar to those seen in men. For men, with adjustment for age, ANA presence was inversely associated with detection of concentrations of bromoxynil in winter or spring samples and recent occupational use of 2,4-dichlorophenoxyacetic acid, and the positive ANA predictors included having a BMI in the obese (BMI > 30.04 kg/m2) category, recent occupational use of trifluralin or fungicides, and current exposure to oilseed, poultry, or dairy production. The inverse association between ANA detection and bromoxynil exposure observed in farmers in this study is consistent with earlier empirical observations that certain pesticides may suppress immune function. Further research is needed to examine whether these findings are confirmed in other populations and to elucidate the biological mechanisms involved.

The use and abuse of commercial kits used to detect autoantibodies

The detection of autoantibodies in human sera is an important approach to the diagnosis and management of patients with autoimmune conditions. To meet market demands, manufacturers have developed a wide variety of easy to use and cost-effective diagnostic kits that are designed to detect a variety of human serum autoantibodies. A number of studies over the past two decades have suggested that there are limitations and concerns in the use and clinical application of test results derived from commercial kits. It is important to appreciate that there is a complex chain of users and circumstances that contributes to variations in the apparent reliability of commercial kits. The goal of this review is to identify the principal links in this chain, to identify the factors that weaken the chain and to propose a plan of resolution. It is suggested that a higher level of commitment and partnership between all of the participants is required to achieve the goal of improving the quality of patient care through the use of autoantibody testing and analysis.

Autoantibodies to chromatin components in juvenile rheumatoid arthritis

OBJECTIVE

To characterize autoantibodies to chromatin components in patients with juvenile rheumatoid arthritis (JRA).

METHODS

The sera of 50 children with JRA were analyzed for antinuclear antibodies (ANA) by immunofluorescence and enzyme-linked immunosorbent assay (ELISA) techniques.

RESULTS

By immunofluorescence, ANA and antibodies to high-mobility group proteins or to DNA-free histones were common in patients with pauciarticular JRA and rheumatoid factor-positive polyarticular JRA. However, reactivity with histone-DNA complexes was rare.

CONCLUSION

Because antihistone antibodies detected by ELISA failed to bind chromatin or other histone-DNA complexes, they are not likely to represent the immunofluorescent ANA activity in serum.

Autoantibody studies in juvenile rheumatoid arthritis

Early studies showed few immunologic abnormalities in juvenile rheumatoid arthritis (JRA) patients. There were no specific laboratory markers useful for diagnosis and assessment of the course of disease in JRA. Previous work showed an association of antinuclear antibodies (ANA) with early-onset pauciarticular disease and iridocyclitis. Similarly, the presence of 19S immunoglobulin (Ig) M rheumatoid factors (RF) was associated with late-onset polyarticular disease in girls. More recent studies have detected many unique autoantibodies. Newer assays show 19S IgM RF in up to 35% of JRA patients, although still mainly in girls with late-onset polyarticular disease. Hidden 19S IgM RF can be shown in up to 75% of JRA patients using different procedures, primarily in those with active polyarticular-or pauciarticular-onset disease. Immune complexes have been detected in JRA patients by means of different techniques; their presence usually correlates with active disease. Studies on a specific ANA in JRA have shown no common extractable nuclear antigen, but antihistone antibodies have been found in up to 75% of cases, again mainly in those with pauciarticular onset and iritis. Finally, a variety of unusual immunologic proteins have also been detected, including anti-ocular, anti-cellular, anti-cardiolipin, anti-perinuclear factor, and anti-collagen antibodies. This review evaluates the significance of these antibodies that can now be found in JRA.

Intra-articular steroids in pauciarticular juvenile chronic arthritis, type 1

The use of intra-articular steroids in one or both knees was evaluated in 21 children with type 1 pauciarticular juvenile chronic arthritis (JCA). The beneficial effect of the injection was noted within 3 days with no significant adverse reactions. Remission exceeding 6 months was seen in 70% of the knees and the arthritis remained inactive during the follow up period in 37%. The beneficial effect of the injection did not correlate with sex, age of onset or the presence of antinuclear antibodies or HLA-B27 antigen and there was no relationship with the size of involved joints at onset, the ESR at onset, or the presence of uveitis. Intra-articular corticosteroids in this type of JCA may provide prompt relief of swelling and pain and reduce the need for other forms of therapy. Remission was long lasting in the majority of the children.

Antihistone antibodies in antinuclear antibody-positive juvenile arthritis

The binding of antinuclear antibody-positive juvenile arthritis (JA) sera to bovine thymus histones H1, H2A, H2B, H3, and H4 was studied by an enzyme-linked immunosorbent assay. Seventy-five percent of the JA patients tested positive for at least 1 antibody specificity. Antihistone antibodies were predominantly IgM, while IgG antibodies were less common and were restricted to histones H1 or H3. In the group of patients with JA of pauciarticular onset, antihistone antibodies were significantly more elevated in patients with past or present uveitis than in patients without a history of uveitis. Anti-H1 antibodies in JA patients were found to react mostly with determinants located in the carboxyl-terminal domain of the H1 molecule. Sera were also reactive with human histone H1(0) or chicken histone H5, which are H1 variants found only in nondividing cells.

Autoantibodies in patients with juvenile chronic arthritis and their immediate family relatives

Antibodies to nuclear antigens were assessed in 23 children with juvenile chronic arthritis (JCA) and 66 of their first degree relatives. Serum samples from 16 patients with JCA (70%) and nine relatives (14%) had antinuclear antibodies by indirect immunofluorescence. Antibodies against nuclear antigens in rabbit thymus extract or an erythroblastoid cell line (K562) were detected by countercurrent immunoelectrophoresis and immunoblotting in 16 patients (70%) and 39 family relatives (59%). Immunoblotting did not show any banding patterns common to all patients with JCA, though bands in the 43-45 kD range were detected in 5/23 patients. Anticardiolipin antibodies were found in 7/23 patients. In total, 18/20 families (90%) had members other than the probands with detectable autoantibodies. In five families immunoblotting showed common banding patterns between the probands and other members. This suggests that there might be an inherited trend towards autoimmune responses in some families of patients with JCA.