Abstract: Dennis McGonagle and colleagues (Oct 3, p 1137)1McGonagle D Gibbon W Emery P Classification of inflammatory arthritis by enthesitis.Lancet. 1998; 353: 1137-1140Summary Full Text Full Text PDF Scopus (390) Google Scholar have put forward their hypothesis of enthesitis as the unifying notion of spondyloarthropahy on the basis of the involvement of entheseal structures in peripheral arthritis in spondyloarthropathy patients. Enthesitis has been long recognised as being associated with spondyloarthropathy, and enthesopathy is an established part of the European classification criteria for spondyloarthropathy.2Dougados M van der Linden S Juhlin R et al.The European Spondylarthropathy Study Group preliminary criteria for the classification of spondylarthropathy.Arthritis Rheum. 1991; 34: 1218-1227Crossref PubMed Scopus (2054) Google Scholar Whereas spondylitis is partly thought to be due to local enthesitis, this is considerably less clear for the major spinal manifestation of spondyloarthropathy, sacroiliitis. Nevertheless, enthesitis shown by magnetic resonance imaging in knee joints is new and interesting for pathogenesis, and possibly also for the clinical classification of spondyloarthropathy. However, the speculation and hypothesis based on these results confuses rather than clarifies the idea of spondyloarthropathy and its differences from other rheumatic diseases such as rheumatoid arthritis. To classify spondyloarthropathy as acute and rheumatoid arthritis as chronic is not correct since about 20% of HLA-B27-positive patients with reactive arthritis3Leirisalo-Repo M Prognosis, course of disease, and its treatment of the spondyloarthropathies.Rheum Dis Clin North Am. 1998; 24: 737-751Summary Full Text Full Text PDF PubMed Scopus (113) Google Scholar and 50–60% of HLA-B27-positive patients with inflammatory bowel disease progress to ankylosing spondylitis, which is clearly a chronic disease. Furthermore, although there are no good comparisons between ankylosing spondylitis or other spondlyoarthropathy subsets and rheumatoid arthritis, the burden of illness seems to be similar in patients with severe ankylosing spondylitis and severe rheumatoid arthritis.4Zink A Braun J Listing A Wollenhaupt J German Colloborative Research Centers. The burden of illness in ankylosing spondylitis is comparable.Arthritis Rheum. 1997; 40: S227Google Scholar The classification criteria for spondyloarthropathy2Dougados M van der Linden S Juhlin R et al.The European Spondylarthropathy Study Group preliminary criteria for the classification of spondylarthropathy.Arthritis Rheum. 1991; 34: 1218-1227Crossref PubMed Scopus (2054) Google Scholar have led to advances in clinical diagnosis, epidemiology, and research. McGonagle and colleagues tend to mix up spondyloarthropathy on the basis of the presence or absence of enthesitis, with various rheumatic diseases such as remitting seronegative symmetric synovitis with pitting oedema (RS3PE), synovitis-acne-pustolosis hyperostosis osteomyelitis (SAPHO), Lyme arthritis and even osteoarthritis. Thus rheumatic diseases should not be separated into rheumatoid arthritis-like and enthesitis-associated entities because this seems to be a step backward. There is good evidence in reactive arthritis that bacteria are present in the synovial membrane; therefore, synovitis can be explained by the presence of bacterial antigens in the synovium that induce a local immune response against foreign antigens. There is no reason why this mechanism should not lead to synovitis without enthesitis. McGonagle and colleagues do not discuss the role of HLA B27. Peripheral arthritis is only weakly associated with HLA B27, whereas a high association can be found with sacroiliitis, enthesitis, and uveitis.5Sieper J Braun J Triggering mechanisms and T cell responses in the spondyloarthropathies.in: Calin A Taurog A The sponduylarthritides. Oxford University Press, Oxford1998: 195-206Google Scholar Thus, although most of the peripheral arthritis in spondyloarthropathy seems to be HLA-B27 independent, it might well be that enthesitis is responsible for peripheral arthritis in some of the patients, especially in those who are HLA-B27 positive. Peripheral joint involvement in spondyloarthropathy could either manifest as primary synovitis possibly affecting also entheseal structures or as primary enthesitis involving other synovial structures as suggested by McGonagle and colleagues.1McGonagle D Gibbon W Emery P Classification of inflammatory arthritis by enthesitis.Lancet. 1998; 353: 1137-1140Summary Full Text Full Text PDF Scopus (390) Google Scholar Spondyloarthropath yAuthors' reply Full-Text PDF
Publication Year: 1999
Publication Date: 1999-05-01
Language: en
Type: letter
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 1
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