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 wa s measured in sera from either HLA-B27-positive (HLA-B27(+)) or HLA-B2 7-negative (HLA-B27(-)) patients with classical ankylosing spondylitis (n = 54). These sera were compared with sera from patients with vario us rheumatic diseases (n = 82) and HLA-B27(+) or HLA-B27(-) healthy in dividuals (n = 85). All sera were analyzed by means of an enzyme-linke d 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, K 36, and K50 than the sera from HLA-B27(-) ankylosing spondylitis patie nts, patients with psoriatic arthritis, systemic lupus erythematosus, rheumatoid arthritis, or reactive arthritis after Yersinia enterocolit ica infection, or healthy controls (P < 0.02). The antibodies were of the immunoglobulin G type. No significant antibody response to the oth er 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 sugg est a specific association between these capsular types and HLA-B27(+) ankylosing spondylitis and might imply their predominance in this dis ease.