Pulmonary Langerhans cell histiocytosis "de novo" after lung transplantation

A pulmonary Langerhans cell histiocytosis is presented in a 40 year-old woman two years after bilateral lung transplantation for emphysema without any signs of Langerhans cells proliferation in the explanted lungs. A microsatellite molecular analysis showed the proliferating cells were generated in a recipient cellular clone. The patient did not quit smoking after transplantation. No signs of disease were detected in the implanted lungs before surgery. Strict control of immunosupressive drug levels stabilized the disease. A "de novo" monoclonal origin of stem cells, probably from the bone marrow is suggested. The reason she did not develop disease in the native lungs is unknown, although we suggest an interaction between tobacco or some other antigens and local cellular receptors.