Abstract
Twenty three anti-Klebsiella antisera were tested for their cytotoxic activity and four for their binding capacity for peripheral blood lymphocytes (PBL) from patients with HLA-B27 positive ankylosing spondylitis (AS+B27+) and from B27 positive (AS-B27+) and B27 negative (AS-B27-) healthy individuals. None of the antisera showed specific activity against PBL from any particular group. The antisera tested included two anti-Klebsiella K43 sera provided by an Australian group, who have reported them to be specifically cytotoxic for AS+B27+ PBL, four antisera raised against a Klebsiella K43 strain provided by this group, and an antiserum from another group, who have reported it as having increased binding capacity for AS+B27+ and AS-B27+ PBL compared with AS-B27- PBL. The results of other workers who have attempted to reproduce the results of either group are reviewed and the possible reasons for the repeated failure to confirm the reported findings are discussed.