QUANTITATIVE AND MORPHOMETRIC ANALYSIS OF LANGERHANS CELLS IN NON-EXPOSED SKIN IN RENAL-TRANSPLANT PATIENTS

Renal transplant recipients have a high incidence of cutaneous complications such as neoplasia and viral or fungal infections. Morphologic alterations of epidermal Langerhans cells (LC) have furthermore been described in these patients. Since these changes have been mainly found in sun-exposed skin, a direct effect of immunosuppressive therapy remains a matter of discussion. A quantitative and morphometric study of epidermal LC in non-exposed skin was performed in 28 renal transplant patients (RTP). RTP were divided in two groups according to immunosuppressive treatment: group A; azathioprine + prednisone (14 cases) and group B; cyclosporine + prednisone (14 cases). Twenty sex-age matched non-immunosuppressed patients acted as controls (group C). Epidermal sheets were obtained by incubation in EDTA and stained for ATPase activity and with the monoclonal antibody T6 (CD1) using the avidin-biotin peroxidase method. Langerhans cells were counted using a calibrated graticule (400X) and expressed as the mean number of LC/mm2. The mean area of the LC and the number of primary dendrites (pd) and secondary dendrites (sd) were determined with a morphometer adapted to an Apple II computer. The mean number of positive cells in controls was: ATPase, 677 +/- 157; T6, 695 +/- 164. Patients in group A had the maximum reduction in both ATPase and T6 LC density (ATPase, 339 +/- 142; T6, 402 +/- 194). Patients in group B had an intermediate reduction in the number of LC (ATPase, 494 +/- 121; T6, 529 +/- 112). The mean area of the LC and mean number of primary but not sd were significatively higher in RTP (area = 274 +/- 65 mu-2; pd = 3.1 +/- 0.3) than in controls (area = 213 +/- 62-mu-2; pd = 2.8 +/- 0.3). We conclude that RTP have a diminished number of LC in non-exposed skin and that this decrease is more pronounced in patients receiving azathioprine and prednisone than in patients receiving cyclosporin and prednisone. Langerhans cells in RTP also show hypertrophic changes. These results suggest a role for the immunosuppressive therapy in the pathogenesis of the LC alterations in RTP.