Current Knowledge of the Etiology and Pathogenesis of Chronic Uveitis Accompanying Juvenile Rheumatoid Arthritis

Ophthalmologic examinations in children with juvenile rheumatoid arthritis

Unlike the joints, ocular involvement with juvenile rheumatoid arthritis is most often asymptomatic; yet, the inflammation can cause serious morbidity with loss of vision. Scheduled slit-lamp examinations by an ophthalmologist at specific intervals can detect ocular disease early, and prompt treatment can prevent vision loss.

Uveitis bei rheumatologischen Erkrankungen im Kindesalter

Children with juvenile chronic arthritis are at risk to develop intraocular inflammation depending on the type of arthritis. The pathogenic mechanisms are unclear; however, an association with antinuclear antibodies is well known. In particular young girls with oligoarticular onset of arthritis are affected most often. Regular ophthalmologic examinations should allow early diagnosis and effective therapy. Complications such as synechiae, cataract, or macula edema are seen especially in uveitis patients with late diagnosis and insufficient anti-inflammatory therapy. Better therapeutic regimens have led to a better overall prognosis of intraocular inflammation in recent years.

Juvenile arthritis-associated uveitis: visual outcomes and prognosis

BACKGROUND

The current issues in the management of uveitis associated with juvenile arthritis revolve mainly around the treatment of mild disease and how to treat patients with more severe disease. The aims of this study were to determine the incidence of uveitis in a cohort of patients with juvenile arthritis as well as the nature of treatment and the risk factors for visual loss.

METHODS

Review of the charts of 71 patients with juvenile arthritis, as defined by the American Academy of Rheumatology, seen between 1992 and 2001 at a combined rheumatology and ophthalmology clinic. Information collected included the patient's sex, age at diagnosis of arthritis and uveitis, and date of diagnosis of arthritis and uveitis. The rheumatologic diagnosis, results of serologic testing, and details of systemic and topical treatments were also recorded.

RESULTS

There were 47 girls and 24 boys ranging in age from 16 months to 13 years. The median age at diagnosis of juvenile arthritis was 4 years and 1 month. Twenty-seven patients (38%) had uveitis. The median age at uveitis onset was 5.9 years, with an average interval of 18 months from the diagnosis of arthritis; 11 patients had uveitis at the time of arthritis diagnosis. There was a positive relation between anti-nuclear antibody positivity and the development of uveitis (p < 0.05). Thirteen (48%) of the 27 patients with uveitis had mild anterior segment inflammation, with fewer than 25 cells in the anterior chamber. This group had spontaneous resolution of uveitis without topical therapy. All the patients without uveitis had a final visual acuity of 6/9 or better. Five of the patients with uveitis had a final visual acuity of 6/36 or worse. Cataract was the most common complication affecting visual outcome. Cataract extraction initially improved the visual acuity, but posterior segment complications and glaucoma compromised the final visual outcome.

INTERPRETATION

We found an incidence of uveitis of 38% with long-term follow-up of patients with juvenile arthritis; the uveitis was diagnosed an average of 18 months after the arthritis. Almost half of the patients with uveitis had minor anterior segment inflammation. These patients did not receive topical treatment and had good visual outcomes. Patients with uveitis at the time of diagnosis of arthritis tended to have a worse visual prognosis and experienced persistent uveitis despite treatment. In this series, cataract extraction was beneficial in improving visual acuity immediately postoperatively, but posterior segment changes and glaucoma may compromise final visual outcomes.

Prevalence of uveitis in an outpatient juvenile arthritis clinic: onset of uveitis more than a decade after onset of arthritis

PURPOSE

To determine the prevalence and severity of uveitis in an outpatient pediatric arthritis clinic in the midwestern United States during the 1990s.

METHODS

The prevalence and clinical characteristics of uveitis were studied retrospectively for all children diagnosed with arthritis at Shriner's Hospital for Crippled Children and followed by the pediatric rheumatology and ophthalmology units of the St Louis Children's Hospital between 1992 and 1995.

RESULTS

Seven children (9%) developed uveitis in a population of 78 patients with juvenile arthritis. Six of the seven children were female, and all six females had anti-nuclear antibody (ANA)-positive, juvenile rheumatoid arthritis (JRA). The prevalence of anterior uveitis in females with ANA-positive, pauciarticular JRA was 20%, and in polyarticular JRA, 17%. One of the girls with uveitis had combined JRA and sarcoidosis; the boy with uveitis had juvenile spondylitis. Arthritis preceded the onset of uveitis in each child by 1 to 13 years (average, 6.4 years). Progression of the uveitis in three of the children resulted in band keratopathy and cataract, causing significant visual loss in two (i.e., in 29% of the children who developed uveitis).

CONCLUSION

The prevalence and ocular morbidity of uveitis in juvenile arthritis appears to have remained relatively stable over the last 2 decades. Onset of the uveitis in several of the children in our study population occurred more than a decade after the diagnosis of arthritis. Girls with ANA-positive JRA and boys with juvenile spondylitis may need to be followed by periodic slit-lamp examination for longer periods than recommended previously.

Immunohistochemical and cytokine analysis of eyes from rats with adjuvant arthritis

Adjuvant induced arthritis in the rat is an animal model of juvenile chronic arthritis (JCA). An anterior uveitis may also develop in this model which closely resembles that seen in association with JCA in the human. Female Lewis rats (150-225 g) were injected intradermally with either Freund's complete adjuvant (FCA, n=5) or Freund's incomplete adjuvant (FIA, n=5). Eyes were examined by slit-lamp biomicroscopy every two days, and the animals sacrificed 21 days post-immunisation. Aqueous humour and serum interleukin-6 (IL-6) levels were determined using the B(9) bioassay, and serial tissue sections of the globes were stained with a variety of monoclonal antibodies. In the FCA group, arthritis was detected in two rats, but no rats from either group developed clinical uveitis. Immunohistochemical analysis revealed greater numbers of macrophages and MHC class II+ve cells in the irises and ciliary bodies of FCA treated rats than were seen in the FIA group. No other cellular infiltrate was detected. Serum IL-6 levels were greater in the FCA group (range 6-122 U/ml, median 42) than the FIA group (range 2-27, median 3) (p=0.018), the highest values seen in the two rats which developed arthritis (100, 122 U/ml). In the aqueous of both groups, IL-6 levels were <5 U/ml, and albumin levels were not significantly different (FCA median=2.0 mg/ml, FIA median=1.8). The authors″ results suggest that in the adjuvant induced arthritis model, infiltration with macrophages and MHC class II+ve cells occurs in the absence of clinical uveitis.

Immunological aspects of juvenile rheumatoid arthritis

This article reviews the evidence from recent studies on immunological abnormalities associated with pathophysiologic mechanisms operating in three clinical subtypes of juvenile rheumatoid arthritis (JRA) (polyarticular, pauciarticular and systemic). The main discussion is focused on three hallmarks of immunopathological studies. First, abnormalities in phenotype and function of lymphocytes from peripheral blood and inflamed synovium are discussed. The aberrations of lymphocytes are elucidated by T and B cells expressing phenotypic cell-markers such as CD20, CD21, CD4, CD8 and DR in association with different subtypes and disease activity. The functional imbalance and impairment of T and B cells are mainly observed by abnormal proliferation and/or in vitro Ig production in response to mitogens and alloantigens. Second, because the appearance of rheumatoid factors (RF) in serum indicates that the pathogenesis of JRA may be based on the autoimmune mechanism, the prevalence of RF including IgM, IgA and IgG isotype, hidden IgM RF and cross-reactive idiotype RF, and their characteristic properties are discussed. Moreover, specific auto-antibodies (antinuclear antibodies and others) for JRA are illustrated in this paper. Third, the production of various pro-inflammatory cytokines resulting in the release of tissue-damaging chemical mediators is also discussed. This may play a central role in the generation of systemic inflammation and joint involvement in JRA.

Serum antiocular antibodies in patients with juvenile rheumatoid arthritis

Although the uveitis associated with juvenile rheumatoid arthritis (JRA) is presumed to have an autoimmune etiology, its pathogenesis is unknown. We utilized immunohistochemical techniques to detect the presence of serum antibodies directed against ocular tissues in these patients. The staining patterns of serum from patients with JRA, with and without uveitis, were compared with normal controls. Antibodies directed against epitopes in iris and ciliary body basement membranes, lens epithelium and fibers, Bruch's membrane, and iris and retinal blood vessels were observed in the sera of several individuals. These staining patterns were statistically more frequent among the pauciarticular and polyarticular JRA patients, with and without uveitis, than either the systemic JRA or normal populations. These results demonstrate the presence of antiocular antibodies in the sera of JRA patients, with and without uveitis. Whether those nonuveitic JRA patients with antiocular antibodies will develop uveitis is unknown at this time.

Autoantibodies to nonhistone chromosomal proteins HMG-1 and HMG-2 in sera of patients with juvenile rheumatoid arthritis

IgG antibodies against the high mobility group (HMG) nonhistone chromosomal proteins HMG-1 and/or HMG-2 were detected in the sera of 49 (39%) of 126 antinuclear antibody (ANA)-positive patients with juvenile rheumatoid arthritis (JRA), by immunoblotting. Clinical diagnosis classified these patients in 2 major groups, 105 with pauciarticular-onset JRA and 21 with polyarticular-onset JRA. Anti-HMG-1 and/or anti-HMG-2 antibodies were found in 8 (25%) of 32 pauciarticular-onset JRA patients with uveitis and in 34 (47%) of 73 patients without uveitis, whereas anti-HMG-1 and/or anti-HMG-2 antibodies were found in 4 (24%) of 17 children with polyarticular-onset JRA without uveitis. Among 53 sera from ANA-negative JRA patients, 3 (6%) were positive for anti-HMG-1 and/or anti-HMG-2 antibodies, whereas no reactivity to HMG-1 or HMG-2 proteins was observed in 48 sera from age-matched children with nonrheumatic diseases.

Antibodies to histones H1 and H5 in sera of patients with juvenile rheumatoid arthritis

The specificity of juvenile rheumatoid arthritis (JRA) sera for histone subclasses was examined by immunoblotting. Antibodies to H1 alone were found in 4 of 21 pauciarticular-onset JRA sera, 4 of 19 polyarticular-onset JRA sera, and 2 of 11 systemic-onset JRA sera. Antibodies to H5 alone were found in 1 of 21 pauciarticular JRA sera, 1 of 19 polyarticular JRA sera, and 3 of 11 systemic JRA sera. Antibodies to both H1 and H5 were found in 4 of 21 pauciarticular JRA sera, 4 of 19 polyarticular JRA sera, and 1 of 11 systemic JRA sera. Antibodies to the core histones (H2A and H2B) were found in 1 of 21 pauciarticular JRA sera, 1 of 19 polyarticular JRA sera, and no systemic JRA sera. No reactivity to histones was observed in 30 sera from age-matched children with nonrheumatic diseases. The presence of H1 and H5 antibodies did not correlate with antinuclear antibody titers or with a homogeneous pattern of immunofluorescence. The predominance of H1 and H5 antibodies and relative absence of antibodies binding to core histones in JRA contrast with findings in adult systemic lupus erythematosus. Further, the presence of antibodies to H5 alone in some of the JRA patients indicates that the immune response in these patients is directed to determinants that are not shared by sequences of mammalian proteins.

Autoantibody profile in juvenile chronic arthritis

Patients with juvenile chronic arthritis (JCA) may be subdivided into a minority, who carry IgM rheumatoid factor and have erosive polyarthritis resembling adult rheumatoid arthritis, and the majority (90%), who are seronegative by conventional means. Between 30 and 60% of patients with JCA have positive antinuclear antibodies (ANAs) according to the choice of substrate for indirect immunofluorescence. The importance of ANAs is the frequent development of associated asymptomatic chronic iridocyclitis, which may impair vision causing worse handicap than the arthritis, which remains predominantly pauciarticular in two thirds of these young children. ANA positive patients rarely possess antibodies to deoxyribonucleic acid (DNA) or extractable nuclear antigens (ENA), and current studies suggest that several different nuclear antigens, including histones, may be involved.