Introduction: Steroids represent a mainstay of immunosuppression after kidney transplant. The infiltration into the graft of active T cells following KT depends on the expression of chemokines and their interaction with their T-cell receptors. However, the natural history of the expression of these molecules in patients who undergo steroid withdrawal after transplant is unknown.
Materials and Methods: In a controlled clinical trial (NCT02284464), a total of 176 KT patients  with low immunological risk were recruited to randomly receive either conventional triple immunosuppression: steroids, TAC and MMF (Group A) versus steroid withdrawal at the 3 post-KT month (Group B). We compared the evolution of CCR4highCD4+ and CXCR3highCD4+ lymphocyte subpopulations in graft blood (GB) extracted by fine needle aspiration puncture determined by flow cytometry in patients after steroid withdrawal at the 3 month post-KT versus patients who continue to receive conventional triple immunosuppression. Measurements were made at 3 (baseline) and 6 months post-KT in GB and in peripheral blood (PB).
Results: So far, 68 patients have been randomized (34 in each group). There were no significant differences in the clinical and demographic characteristics between the groups at baseline. The first analysis (at 3 months) in those patients who had completed 6 months of follow-up (Group A: n=13; Group B: n=15) showed a significant increase in the CCR4highCD4 subpopulations in GB versus PB in both groups. However, at six months a significant increase in GB versus PB was only seen in Group A. There were no significant differences in the CXCR3highCD4+ lymphocyte subpopulation at the third or sixth month between GB and PB in either group (Table).
Conclusion: These preliminary results could suggest a possible effect of prednisone that would favor the recruitment of CCR4highCD4+ cells into the renal graft.