Tacrolimus increases inflammatory cells in lung

Immunosuppression for solid organ transplantation has evolved to target multiple immune pathways with the hope of decreasing both acute and chronic allograft rejection. Tacrolimus and mycophenolate have now become the most widely used combination for maintenance immunosuppressive regimens after lung transplantation in comparison with cyclosporine and azathioprine. However, limited information is available with respect to their effects on cells other than those from the immunologic compartment. We hypothesized that tacrolimus could affect the inflammatory profile in lung and systemic circulation. Sixty Wistar rats were divided into two groups: control, saline solution 0.9% (2.5 mL/kg) and tacrolimus (1 mg/kg). Animals were treated by gavage daily for 7, 15 or 30 days. After these periods, inflammatory cell counts were performed in bronchoalveolar lavage (BAL), blood smears and lung tissue. In BAL, the number of total cells, macrophages, eosinophils and lymphocytes in tacrolimus-treated animals were higher at 15 days (p≤0.020). In blood smears, tacrolimus group showed at 15 and 30 days less neutrophils and monocytes (p=0.001) and more lymphocytes (p=0.001). In lung tissue, mononuclear and polymorphonuclear cells were increased in tacrolimus group at 7, 15 and 30 days (p=0.001). Tacrolimus induced higher influx of inflammatory cells in lung tissue but decreased these cells on systemic circulation up to 30 days.