Cellular immune response to Klebsiella pneumoniae antigens in patients with HLA-B27+ankylosing spondylitis

Objective. To study the reactivity of peripheral blood mononuclear cells (P BMC) of patients with ankylosing spondylitis (AS) and rheumatoid arthritis (RA) and healthy controls to Klebsiella pneumoniae antigens and to the GroE L-like proteins from K. pneumoniae (HSP60Kp) and Mycobacterium leprae recom binant heat shock protein 65 (rHSP65Ml). Methods. PBMC of 13 patients with AS and 9 with RA and 10 controls were sti mulated in vitro by heat shook induced K. pneumoniae antigens in a cell blo t assay, by insolubilized HSP60Kp, by cytosolic proteins (CP) from K. pneum oniae cultivated at 37 degrees C or 45 degrees C, by soluble HSP60Kp, or by rHSP65Ml. Results. In the cell blot assay 7/13 AS and 3/9 RA patients responded to fr action 4, which contains mainly HSP60Kp, and no controls responded (AS vs c ontrols: p = 0.007). The response to the insolubilized HSP60Kp was positive in 6/13 AS patients but negative in RA patients and controls (p = p < 0.00 4). The response to CP45 degrees C was positive in 7/13 AS, in 2/9 RA, and no controls (AS vs controls. P < 0.015). Response to the soluble HSP60Kp wa s found in 7/13 AS and 5/9 RA patients, but no controls (AS vs controls: p = 0.0075). Response to rHSP65Ml was positive in 3/13 AS, 7/9 RA patients, a nd 1/10 controls (AS vs RA: p = 0.027; RA vs controls: p = 0.005; AS vs con trols: nonsignificant). Conclusion. In PBMC of the majority of patients with AS and in some with RA , but not in healthy controls, there an cells that proliferate in the prese nce of HSP60 of K. pneumoniae.