Goto R, You S, Zaitsu M, Chatenoud L, Wood KJ. Delayed anti-CD3 therapy results in depletion of alloreactive T cells and the dominance of Foxp3(+) CD4(+) graft infiltrating cells. Am. J. Transplant. 13(7), 1655-1664 (2013). Humanized Fc receptor nonbinding anti-CD3 monoclonal antibodies have been tested in patients with autoimmune diseases with the goal of inducing immune tolerance. However, the timing of drug administration may be an important determinant of the biologic effects, since not all T cells are equally affected, and there may be different subsets of cells involved during the evolution of immune responses. The study by Goto et al. showed that delayed administration of anti-CD3 therapy was more effective in depleting alloreactive T cells than administration at the time of transplant, and resulted in long-term survival of the graft by promoting infiltration of CD4 Tregs into the graft.