“…Another group of workers has demonstrated that antisera raised against certain strains of K. pneumoniae are cytotoxic for B27 positive lymphocytes from AS patients, but not for B27 positive controls (Seager et al 1979;Geczy & Yap, 1979;Geezy, Alexander & Bashir, 1980). The purpose of this paper is to describe and identify the klebsiellas isolated by one of us (D. C.) from AS patients, in order to see if there is any detectable distinguishing feature about them, as opposed to those found in non AS patients and other environments (Cooke et al 1979a(Cooke et al , b, 1980Edmondson et al 1980). …”