Molecular mimicry and ankylosing spondylitis: possible role of a novel sequence in pullulanase of Klebsiella pneumoniae

Abstract

Molecular mimicry has been shown between two sequences of Klebsiella pneumoniae pulD secretion protein (DRDE) with HLA‐B27 (DRED) and pulA (pullulanase) enzyme (Gly‐X‐Pro) with types I, III and IV collagen respectively. IgG antibody levels in AS patients were elevated against 16mer synthetic peptides of HLA‐B27 and pulD by enzyme linked immunosorbent assay (ELISA) compared to controls (P < 0.001). ELISA assays against K. pneumoniae grown in the absence and presence of pullulan demonstrated significant levels of IgA antibody in AS patients compared to controls (P < 0.001). Increased IgA and IgG antibody levels to pulA and types I and IV collagen were observed in AS patients compared to controls (P < 0.001). These observations could be relevant in the sequence of molecular events in AS.