A spectrum of donor-specific indirect pathway T-cell responses that corresponds to immune responsiveness is present in renal transplant recipients, say researchers. Haynes et al. analyzed peripheral blood of 45 renal transplant recipients divided into five groups ranging from most tolerant to least tolerant: identical twins, clinically tolerant patients, patients on steroid monotherapy, patients on standard immunosuppression and patients with chronic allograft rejection. The antidonor indirect pathway was active in all but the twins. The indirect pathway T-effector response increased across patient groups, whereas the antidonor indirect pathway T-regulatory response decreased across the groups.