Correlation between the immune responses to collagens type I, III, IV and V and Klebsiella pneumoniae in patients with Crohn's disease and ankylosing spondylitis

Background. Increased levels of collagen types I, III and V are found in strictures of patients with Crohn's disease (CD) compared with normal gut tissue. Type IV collagen is present in the basement membranes, basal lamina, retina and cornea. Elevated levels of antibody to Klebsiella pneumoniae are found in both active CD and active ankylosing spondylitis (AS) patients compared with healthy controls. Methods. Reactivities for immunoglobulin class‐specific antibodies (IgM, IgG and IgA) against collagen types I, III, IV, V and whole K. pneumoniae were measured by ELISA in nine patients with early CD and 10 with late CD from King's College Hospital and 12 late CD patients and 36 HLA‐B27‐positive AS patients from Middlesex Hospital and was compared with values for 26 healthy controls from the Blood Transfusion Service in London. Results. Levels of class‐specific IgM, IgG and IgA antibodies to collagen types I, III, IV, V and K. pneumoniae were significantly elevated in early and late CD patients compared with healthy controls (P