Acitretin and skin cancer in kidney transplanted patients. Clinical and histological evaluation and immunohistochemical analysis of lymphocytes, natural killer cells and Langerhans' cells in sun exposed and sun protected skin.

BACKGROUND: Renal transplanted recipients have an increased incidence of actinic keratosis and skin cancer. METHODS: In order to examine the chemoprophylatic effects of low-dose acitretin on keratosis and skin cancer development we submitted 13 renal transplanted patients who presented actinic keratosis to acitretin therapy (20 mg/d) for 12 months. The patients were assessed at monthly intervals during the first 6 months and every 2 months until the 12th month for new skin lesions and for acitretin toxicity. Normal skin biopsies of sun exposed and sun protected areas were taken for histopathological examination and submitted to immunohistochemistry technique to demonstrate CD4+ and CD8+ T lymphocytes, natural killer (NK) cells and Langerhans' cells which were counted and compared before, after 6 and 12 months of the treatment. RESULTS: There was an improvement of actinic keratosis in all patients. Only one patient developed new skin cancer. Side-effects were well tolerated and no significant biochemical effects were observed. There were no differences in the microscopic aspects of the skin and in the number of CD4+ and CD8+ T lymphocytes and NK cells. There was a significant increase in the number of epidermal Langerhans' cells after 12 months of acitretin therapy. CONCLUSIONS: The data obtained permit us to conclude that low dose acitretin therapy is safe, well tolerated and partially effective in chemoprophylaxis of skin cancer in renal transplant recipients. The increase in epidermal Langerhans' cells observed may be an expression of the immunomodulatory effect of acitretin.