Lymphocyte subsets and Langerhans cells in the skin of kidney transplant recipients under three different immunosuppressive regimens

Abstract Background Renal transplant recipients (RTRs) are at increased risk of developing skin cancer; however, the role of immunosuppression is not yet fully understood. In this study, we evaluated the immunohistochemical changes in the skin of RTRs under three different immunosuppression regimens: mTOR inhibitors (mTORi), sirolimus or everolimus, mycophenolic acid (MPA) precursors such as mycophenolate sodium or mofetil, or azathioprine (AZA). Methods We evaluated biopsies of sun‐exposed and sun‐protected skin for immunohistochemical quantification of B lymphocytes (CD20 + ), T lymphocytes (CD3 + , CD4 + , and CD8 + ), and Langerhans cells (LCs) (CD1a + ) in 30 RTRs and 10 healthy controls. The RTRs were divided into three groups: mTORi ( n = 10), MPA ( n = 10), and AZA ( n = 10). Results No differences were observed in the number of B lymphocytes. However, a significant decrease in the number of T lymphocytes and LCs was observed in both sun‐protected and sun‐exposed skin in the AZA and MPA groups, although to a lesser degree in the latter group. The skin of the mTORi group did not differ from that of the control group in terms of the number of B and T lymphocytes and LCs. Conclusions Patients treated with mTORi exhibit preserved cellular elements related to cutaneous immune surveillance. The use of AZA induced a greater degree of skin immunosuppression than in the control group, as demonstrated by the decrease in T lymphocytes and LCs.