Absence of donor-derived keratinocyte stem cells in skin tissues cultured from patients after mobilized peripheral blood hematopoietic stem cell transplantation.

OBJECTIVE: Recent studies suggest that primitive bone marrow-derived cells contribute to regeneration of many tissues, including muscle, endothelium, myocardium, neural tissues, liver, and skin. Conversely, primitive cells resident in muscle and other tissues have been reported to reconstitute hematopoiesis. We investigated the contribution of cells with a primitive hematopoietic phenotype to human epidermal skin formation in recipients of allogeneic mobilized peripheral blood hematopoietic stem cell (HSC) transplantation.

PATIENTS AND METHODS: Our study population included female patients who had received granulocyte colony-stimulating factor mobilized peripheral blood HSC transplants from male donors for a variety of benign and malignant hematologic disorders at least 6 months before study entry, with a history of skin graft-vs-host disease. Epidermal skin cells (keratinocytes) obtained from punch biopsies of the skin were cultured under conditions specific for growth and expansion of homogenous populations of keratinocytes from keratinocyte stem cells. After multiple passages, DNA was extracted from cultured cells and evaluated by two different polymerase chain reaction (PCR) method for detection of Y chromosome specific sequences.

RESULTS: Neither sensitive PCR-based technique revealed the presence of male donor-derived keratinocyte stem cells in keratinocytes cultured from skin biopsies of female allogeneic transplantation recipients.

CONCLUSIONS: We could not confirm the contribution of donor mobilized peripheral blood hematopoietic stem cells to keratinocyte stem cell populations after HSC transplantation. These results cannot explain the presence of donor-derived cells with keratinocyte phenotypic markers in tissue sections of HSC transplant recipients.