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Inflammation in HLA-B27-associated diseases
1Department of Bacteriology and Immunology, University of Helsinki, Finland.
Abstract:
The pathogenetic mechanisms in the development of spondyloarthropathies are multifactorial. These include the possible role of infective micro-organisms which can by direct invasion lead to persistence of microbial antigens and thus trigger arthritis or by cross-reactions with the host tissue lead to inflammatory symptoms or by cross-reactions with HLA-B27 trigger cytotoxic T-cell response. After the primary event, exaggerated inflammatory response can lead to amplification of inflammation. The components in the amplification of inflammation include hyperreactive neutrophils and serum factors such as enhanced production of activation products of complement in subjects with HLA-B27. The enhanced neutrophil function seems to persist in patients with previous severe inflammatory symptoms during acute reactive arthritis or in those with late inflammatory complications. The enhancement is probably caused by priming effect by lipopolysaccharide, which seems to persist for a long period in patients with acute reactive arthritis. Enhanced production of monokines can contribute to the enhanced inflammation in patients with spondyloarthropathies. The primed phagocytes can respond vigorously when rechallenged with antigenic load during a new infection, thus leading in some patients to recurrent or chronic inflammatory symptoms. Antimicrobial therapy or sulphasalazine by modifying antigen elimination or absorption can diminish inflammatory response during acute arthritis and in chronic spondyloarthropathies. Long-term follow-up studies are needed to find out whether prolonged therapies with these agents affect the prognosis of spondyloarthropathies.
Insights
Infectious agents and host factors contribute to spondyloarthropathies. Persistent microbial antigens and immune responses can lead to chronic or recurrent inflammation, potentially managed by therapies targeting antigen elimination.
Area of Science:
- Immunology
- Rheumatology
- Microbiology
Background:
- Spondyloarthropathies involve complex, multifactorial pathogenetic mechanisms.
- Infective microorganisms may trigger arthritis through direct invasion, antigen persistence, or cross-reactions with host tissues or HLA-B27.
Purpose of the Study:
- To elucidate the pathogenetic mechanisms in spondyloarthropathies.
- To understand the role of microbial factors and immune responses in disease development and persistence.
Main Methods:
- Review of pathogenetic mechanisms in spondyloarthropathies.
- Analysis of the role of microbial antigens, HLA-B27, neutrophil function, and complement activation.
- Consideration of therapeutic interventions like antimicrobial therapy and sulphasalazine.
Main Results:
- Infectious triggers can lead to persistent antigens and amplified inflammatory responses.
- Hyperreactive neutrophils and enhanced complement activation, particularly in HLA-B27 positive individuals, contribute to inflammation.
- Priming of phagocytes by lipopolysaccharide may lead to recurrent inflammation upon re-exposure to antigens.
Conclusions:
- Spondyloarthropathies result from a combination of microbial triggers and exaggerated host immune responses.
- Therapies modifying antigen elimination or absorption may reduce inflammation in acute and chronic spondyloarthropathies.
- Further long-term studies are required to assess the prognostic impact of prolonged therapeutic interventions.