Association between high interleukin-6 levels and adverse outcome after autologous haemopoietic stem cell transplantation

We studied interleukin-6 (IL-6) levels on the day of transplantation in 31 patients undergoing autologous haemopoietic stem cell transplantation (SCT) (either peripheral blood stem cell transplantation (PBSCT) or bone marrow transplantation (BMT)) for neoplastic diseases to determine if there was a relationship between IL-6 level and rate of haemopoietic recovery, length of stay in hospital, and survival. There was no apparent delay in post-transplant recovery associated with elevated IL-6 levels. However, increased values of IL-6 tended to be associated with an increased length of stay in hospital (P = 0.083). There was a highly significant adverse association between higher IL-6 levels and survival following transplantation (P = 0.0001). This association remained significant (P = 0.013) in the uniform subgroup of patients with malignant lymphoma with chemosensitive disease who had undergone BMT (that is, excluding patients who had undergone PBSCT) (n = 13). Knowledge of IL-6 levels on the day of transplant has the potential to provide valuable prognostic information in patients undergoing autologous haemopoietic SCT.