Individual Lymphocyte Sensitivity to Steroids as a Reliable Biomarker for Clinical Outcome after Steroid Withdrawal in Japanese Renal Transplantation

Recently, steroid reduction/withdrawal regimens have been attempted to minimize the side effects of steroids in renal transplantation. However, some recipients have experienced an increase/resumption of steroid administrations and acute graft rejection (AR). Therefore, we investigated the relationship between the individual lymphocyte sensitivity to steroids and the clinical outcome after steroid reduction/withdrawal. We cultured peripheral blood mononuclear cells (PBMCs) isolated from 24 recipients with concanavalin A (Con A) in the presence of methylprednisolone (MPSL) or cortisol (COR) for four days, and the 50% of PBMC proliferation (IC(50)) values and the PBMC sensitivity to steroids were calculated. Regarding the experience of steroid increase/resumption and incidence of AR within one year of steroid reduction/withdrawal, the IC(50) values of these drugs before transplantation in the clinical event group were significantly higher than those in the event-free group. The cumulative incidence of steroid increase/resumption and AR in the PBMC high-sensitivity groups to these drugs before transplantation were significantly lower than those in the low-sensitivity groups. These observations suggested that an individual’s lymphocyte sensitivity to steroids could be a reliable biomarker to predict the clinical outcome after steroid reduction/withdrawal and to select the patients whose dose of steroids can be decreased and/or withdrawn after transplantation.