Specialized clinical cell processing began in the Department of Transfusion Medicine at the National Institutes of Health in 1984. The number and complexity of procedures performed increased quickly and in 1997 a highly specialized cell processing laboratory was opened. The laboratory has approximately 3,000 square feet, specialized air handing, a highly trained staff, and written laboratory procedures. In addition to standard laboratory equipment, the laboratory has numerous cell isolation instruments, flow cytometers, and automated cell counting instruments. The laboratory supports blood and bone marrow transplant protocols by isolating CD34+ stem cells, removing T lymphocytes, culturing lymphocytes to eliminate donor lymphocytes that are reactive with recipient alloantigens, and stimulating lymphocytes to induce Th2 type cells to reduce graft versus host disease. The laboratory has also been preparing dendritic cells to support protocols using immune therapy to treat cancer. In addition, pancreatic islet cells are isolated from organ donors for transplantation to treat type I diabetes mellitus.