CK18F levels rise prior to the start of immunosuppressive treatment of GVHD and decrease with response to therapy. (A) Individual kinetics of CK18F levels are shown for all 20 patients of our cohort who had serum samples available in the period of 50 days preceding the start/escalation of immunosuppressive therapy of hepato-intestinal GVHD. CK18F data were standardized with respect to their value at the start of immunosuppressive therapy (n = 18) or to the day closest to this clinical decision (n = 2). (B) Individual kinetics of all 23 patients with available serum samples responding to immunosuppressive therapy. CK18F data were standardized with respect to their value at the start of immunosuppressive therapy. As the time point for the resolution of GVHD is difficult to fix, we show CK18F levels at the day of steroid withdrawal (or of withdrawal of ciclosporin if this was the only immunosuppressive drug applied •). Alternatively, the last available sample was used if tapering of steroid treatment was not completed at the end of follow-up (○).