Increased numbers of IgG-containing cells in rectal lamina propria of patients with ankylosing spondylitis

The effects of vasculitis on the gastrointestinal tract and liver

Vasculitis can affect every organ of the digestive system. In many cases, it may first present with gastrointestinal symptoms. In several forms of vasculitis, including Churg Strauss syndrome, Henoch-Schönlein purpura, and lupus, the majority of patients have gastrointestinal involvement. The astute gastroenterologist should consider vasculitic causes of the symptoms seen in many patients. Making the correct diagnosis requires a thorough understanding of the potential role of vasculitis in causing these symptoms and the appropriate path to making a diagnosis. This article reviews the variety of manifestations of vasculitis on the digestive system, and emphasizes diagnosis and clinical manifestations.

Spondylarthropathies: from gut to target organs

Recent studies strongly support the concept that gut and joint inflammation are closely related. Progress also has been made in identifying individual mechanisms that contribute to the pathogenesis of joint disease in IBD and in undifferentiated SpAs. However, the interrelationship of these mechanisms that result in chronic disease manifestations at a site distant from the initiating event remain to be elucidated. The local absence of homing molecule receptors in the gut wall combined with an expression of these receptors in target organs can be responsible for the transformation of the synovial membrane and/or the enthesis into an aberrant tertiary lymphoid organ of the gut.

Comparison of the antibody responses to the 77 Klebsiella capsular types in ankylosing spondylitis and various rheumatic diseases

The production of antibodies to Klebsiella capsular polysaccharides was measured in sera from either HLA-B27-positive (HLA-B27+) or HLA-B27-negative (HLA-B27-) patients with classical ankylosing spondylitis (n = 54). These sera were compared with sera from patients with various rheumatic diseases (n = 82) and HLA-B27+ or HLA-B27- healthy individuals (n = 85). All sera were analyzed by means of an enzyme-linked immunosorbent assay specific to each of the 77 Klebsiella serotypes. The sera from HLA-B27+ patients with ankylosing spondylitis showed a significantly higher antibody frequency to the capsular types K26, K36, and K50 than the sera from HLA-B27- ankylosing spondylitis patients, patients with psoriatic arthritis, systemic lupus erythematosus, rheumatoid arthritis, or reactive arthritis after Yersinia enterocolitica infection, or healthy controls (P < 0.02). The antibodies were of the immunoglobulin G type. No significant antibody response to the other 74 Klebsiella serotypes, noncapsulated mutants of K26, K36, and K50, or preparations of Citrobacter, Serratia, Hafnia, or Morganella spp. or Streptococcus pneumoniae could be detected. The results might suggest a specific association between these capsular types and HLA-B27+ ankylosing spondylitis and might imply their predominance in this disease.

Serum antibodies to Klebsiella capsular polysaccharides in ankylosing spondylitis

OBJECTIVE

To measure antibodies to Klebsiella capsular polysaccharides in the sera of HLA-B27 positive patients with ankylosing spondylitis (AS), compared with HLA-B27 positive and HLA-B27 negative healthy control subjects.

METHODS

Antibodies were detected by means of an enzyme-linked immunosorbent assay specific for each of the 77 known Klebsiella serotypes.

RESULTS

Significantly elevated frequencies and titers of antibodies to capsular polysaccharides K26, K36, and K50 were detected in sera from AS patients, compared with controls.

CONCLUSION

These results suggest the predominance of Klebsiella serotypes K26, K36, and K50 in patients with AS.

The role of infections in the rheumatic diseases: molecular mimicry between bacterial and human stress proteins?

Infections can cause or exacerbate the rheumatic diseases in several ways, including immune cross-reactivity between bacterial heat shock proteins and similar proteins in normal human tissues. This may lead to autoimmunity in rheumatoid arthritis and systemic lupus. In addition, increased activation of the gene regulating the synthesis of a heat shock protein has been found in scleroderma fibroblasts. As an infection-induced model for other rheumatic diseases, rheumatic fever (RF), with its well-established link to prior group A streptococcal infection, will be revisited. The lessons learned from RF and other rheumatic diseases directly linked to infection will be applied to ankylosing spondylitis, rheumatoid arthritis, Sjogren's syndrome and polymyositis, for which a mounting body of circumstantial evidence suggests a probable infectious cause. The interplay of genetic susceptibility and infection with particular organisms and the implications of this new information for present and future therapy of the rheumatic diseases will also be presented.

Immunoglobulin containing cells in terminal ileum and colorectum of patients with arthritis related gut inflammation

In 40 distal ileal and 40 colonic biopsies of arthritic patients mostly without gastrointestinal symptoms, but with histological evidence of acute or chronic inflammation of the gut, the number of immunoglobulin (Ig) containing plasma cells was studied morphometrically using a peroxidase antiperoxidase technique. Compared with controls, the ileal mucosal biopsies showed an increase of IgA and IgG in acute ileitis. In chronic ileitis there was an increase of IgA, IgG, and IgM similar to Crohn's disease. In colonic biopsies there was a significant increase of all immunoglobulin classes in acute inflammation. In chronic inflamed mucosa there was also an increase of all three Ig classes. The Ig distribution, however, was significantly different in acute and chronic colitis. These findings give immunohistochemical evidence of the existence of two different types of inflammation related to reactive arthritis or the peripheral joint involvement of ankylosing spondylitis. The Ig pattern in acute colitis is similar to that found in infectious colitis, suggesting an enterobacterial origin of the arthritis in this group of patients although bacteriological and serological investigations were negative. In the chronic type of arthritis related ileocolitis, the pattern of Ig containing cells is similar to that found in Crohn's disease but different from infectious and ulcerative colitis, which makes the hypothesis that a great number of these arthritis patients suffer from asymptomatic or subclinical Crohn's disease acceptable.

The human gastrointestinal secretory immune system in health and disease

The main function of secretory IgA is to exert immune exclusion; that is, by intimate cooperation with innate non-specific defence mechanisms, it dampens down penetration of soluble antigens and inhibits epithelial colonisation of bacteria and viruses. Secretory IgM may exert a similar protective function in the gut as its local synthesis sometimes is markedly increased, especially in selective IgA deficiency. IgG should not be considered a secretory immunoglobulin because its external translocation depends on passive intercellular diffusion. By activating complement, antibodies of this isotype may cause increased mucosal permeability and tissue damage. IgG may thus contribute to persistent immunopathology in mucosal lesions. The same is true for IgE antibodies which, in atopic individuals, may be carried into the gut mucosa by mast cells and cause their degranulation with histamine release. Secretory IgA and secretory IgM are the products of two cell types: plasma cells synthesise IgA dimers and IgM pentamers which, by non-covalent association, become complexed with the secretory component (SC) which is synthesized by serous-type glandular cells. The adsorption of the Ig polymers to the SC-expressing epithelial cells depends on J chain-determined binding sites. This fact gives biological significance to the striking J chain expression shown by mucosal immunocytes regardless of the Ig class they produce. The immunocytes populating the gut mucosa apparently belong to relatively early memory B cell clones. The obvious functional goal of J chain expression at this stage of clonal differentiation is local generation of SC-binding IgA and IgM polymers. In various gut diseases, altered immune regulation results in a disproportionately increased number of J chain-negative IgG-producing cells in the mucosa. Such altered immunological homeostasis may contribute to perpetuation of inflammatory bowel diseases.