Moderately increased IgG binding to the recall Ags DT and TT in CPB patients after surgery. Serum concentrations of Abs binding to DT and TT were determined by ELISA before (d0), 10 days (d10), and > 4 months after CPB. The Friedman test with a Dunn posttest revealed a significant increase of the concentrations over time in the patient group as a whole (A). The increase was similar in nonresponders (B) and responders (C). Means are shown as solid lines (n = 166). *P < .05; **P < .01; ***P < .001.