The role of infectious agents in the spondylarthropathies

Long-term progression, prognosis, and treatment of patients with recurrent ocular manifestations of Reiter's syndrome

PURPOSE

To investigate the spectrum of ocular involvement, to examine the clinical outcome, and to analyze the influence of treatment in patients with chronic ocular manifestations of Reiter's syndrome (RS) referred to a tertiary care ocular immunology service.

DESIGN

Retrospective, noncomparative, interventional case series.

PARTICIPANTS

Twenty-five patients with RS evaluated at the Ocular Immunology and Uveitis Service of the Massachusetts Eye and Ear Infirmary from 1981 through 2001.

METHODS

Charts of patients were reviewed and data on age, gender, follow-up time, ocular symptoms, extraocular involvement, ocular complications, therapy, and visual acuities were recorded.

MAIN OUTCOME MEASURES

Visual acuity, ocular complications, disease progression, clinical outcome, and systemic treatment.

RESULTS

Twenty-five patients (20 male and 5 female) diagnosed with RS, with a mean age at presentation to our service of 37 years, were studied. The mean follow-up was 48.5 months. Eighty-five percent of patients tested were positive for human leukocyte antigen B27. Sixty-four percent of patients had a positive family history. All patients had oligoarthritis and enthesitis, most commonly affecting the back (56%), Achilles tendon (52%), and sacroiliac joint (24%). Eighty percent had a history of infection, most frequently urethritis (68%). Forty-four percent had a history of mucocutaneous lesions. All patients demonstrated ocular involvement at the time of diagnosis (68% with unilateral and 32% with bilateral disease), 84% had evidence of uveitis, 3% had scleritis, 2% had conjunctivitis, and 1% had pars planitis and iridocyclitis. During follow-up, the ocular complications included conjunctivitis (96%), anterior uveitis (92%), posterior uveitis (64%), keratitis (64%), cataract (56%), intermediate uveitis (40%), scleritis (28%), cystoid macular edema (28%), papillitis (16%), and glaucoma (16%). Systemic treatment for ocular inflammation was initiated in all patients. Ninety-six percent were treated with nonsteroidal anti-inflammatory agents. Eighty-eight percent were treated with corticosteroids, 64% requiring systemic prednisone. Immunosuppressive therapy was initiated in 52% of patients, with all receiving methotrexate. Seven patients required more than one immunosuppressive agent. The mean initial visual acuity was 20/25 in the right eye and 20/30 in the left eye. The mean final visual acuity was 20/25 in the right eye and 20/25 in the left eye.

CONCLUSIONS

Reiter's syndrome may be associated with chronic recurrent ocular inflammation. Systemic therapy (including immunosuppressive treatment) typically is required to control the ocular inflammation and to prevent progressive visual loss.

Absence of autoantibodies to peptides shared by HLA-B27.5 and Klebsiella pneumoniae nitrogenase in serum samples from HLA-B27 positive patients with ankylosing spondylitis and Reiter's syndrome

Some microorganisms which are pathogenic in humans share amino acid sequences with human proteins (molecular mimicry). It has been suggested that molecular mimicry might be a reason for autoimmunity as a result of immunological cross reactivity. A homologous sequence of six amino acids has been found in both Klebsiella pneumoniae nitrogenase and the HLA-B27.5 molecule. In addition, (auto)antibodies to a synthetic peptide that contained the HLA-B27.5/klebsiella mimicking epitope have been detected in serum samples from HLA-B27 positive patients with ankylosing spondylitis and Reiter's syndrome. Confirmation of these data is important, because ankylosing spondylitis and Reiter's syndrome have so far been assumed to be 'seronegative' rheumatic diseases. It was, however, not possible to confirm the presence of autoantibodies against the mimicking peptide in serum samples from patients with ankylosing spondylitis and Reiter's syndrome. Serum samples from 81 patients with ankylosing spondylitis, 38 patients with Reiter's syndrome, and 81 healthy blood donors were tested against the 'mimicking peptide' in an enzyme linked immunosorbent assay (ELISA). Some of the serum samples from patients showed high but non-specific binding to the mimicking peptide. A highly significant correlation between binding to plastic coated with the mimicking peptide, to plastic coated with an irrelevant peptide, and even to non-coated plastic was observed. The nature of the serum component(s) in these patient serum samples (and some control serum samples) responsible for the high non-specific binding to plastic remains unclear. It was also shown that antibodies to the HLA-B27 peptide (containing the mimicking epitope) induced in rabbits do not cross react with the klebsiella peptide and vice versa.

Stress proteins, autoimmunity, and autoimmune disease

At birth, the immune system is biased toward recognition of microbial antigens in order to protect the host from infection. Recent data suggest that an important initial line of defense in this regard involves autologous stress proteins, especially conserved peptides of hsp60, which are presented to T cells bearing gamma delta receptors by relatively nonpolymorphic class lb molecules. Natural antibodies may represent a parallel B cell mechanism. Through an evolving process of "physiological" autoreactivity and selection by immunodominant stress proteins common to all prokaryotes, B and T cell repertoires expand during life to meet the continuing challenge of infection. Because stress proteins of bacteria are homologous with stress proteins of the host, there exists in genetically susceptible individuals a constant risk of autoimmune disease due to failure of mechanisms for self-nonself discrimination. That stress proteins actually play a role in autoimmune processes is supported by a growing body of evidence which, collectively, suggests that autoreactivity in chronic inflammatory arthritis involves, at least initially, gamma delta cells which recognize epitopes of the stress protein hsp60. Alternate mechanisms for T cell stimulation by stress proteins undoubtedly also exist, e.g., molecular mimicry of the DR beta third hypervariable region susceptibility locus for rheumatoid arthritis by a DnaJ stress protein epitope in gram-negative bacteria. While there still is confusion with respect to the most relevant stress protein epitopes, a central role for stress proteins in the etiology of arthritis appears likely. Furthermore, insight derived from the work thus far in adjuvant-induced arthritis already is stimulating analyses of related phenomena in autoimmune diseases other than those involving joints. Only limited data are available in the area of humoral autoimmunity to stress proteins. Autoantibodies to a number of stress proteins have been identified in SLE and rheumatoid arthritis, but their pathogenetic significance remains to be established. Nevertheless, the capacity of certain stress proteins to bind to multiple proteins in the nucleus and cytoplasm both physiologically and during stress or injury to cells, suggests that stress proteins may be important elements in the "immunogenic particle" concept of the origin of antinuclear and other autoantibodies. In short, this fascinating group of proteins, so mysterious only a few years ago, has impelled truly extraordinary new lines of investigation into the nature of autoimmunity and autoimmune disease.