Humoral immune response to Klebsiella capsular polysaccharides in HLA-B27-positive patients with acute anterior uveitis and ankylosing spondylitis

Klebsiella is suggested to trigger ankylosing spondylitis (AS) and acute anterior uveitis (AAU) in HLA-B27-positive individuals. Previous investigations showed an increased antibody response to the Klebsiella capsular types K26, K36, and K50 in sera from HLA-B27-positive AS patients. In the present study the prevalence and titers of antibodies against Klebsiella capsular antigens were measured by means of an ELISA in 32 sera from HLA-B27-positive AAU patients either with (n = 10) or without AS (n = 22) and compared with sera from HLA-B27-negative AS-patients (n = 13). Sera from either HLA-B27-positive (n = 45) or negative (n = 40) healthy individuals served as control. Sera from HLA-B27-positive AAU with or without AS showed significantly higher antibody prevalence and IgG-titers against capsular antigens of the Klebsiella serotypes K26, K36, and K50 when compared with sera from HLA-B27-negative AS patients or with healthy controls. These results might be taken to indicate the predominance of these serotypes in the HLA-B27-associated AS and AAU.