ABSTRACT
The production and purification of diagnostic and therapeutic substances from mammalian somatic cells have been well established in the biomedical field for several years (1-3). However, the use of living cells as therapeutic agents is a recent event. This new area of biotechnology, termed ex vivo cell therapy, is rapidly evolving and has gathered enormous momentum. A greater understanding of cell biology now makes it possible to cultivate, propagate, and manipulate many kinds of living human cells into therapeutically useful modalities. In 1984, we described the first medically relevant example of this therapy when human epidermal keratinocytes were propagated ex vivo into sheets of contiguous epithelium suitable for grafting onto wound beds of patients with massive burn injuries over large body surface areas (4). The result of this approach provides an initial epithelial coverage that later develops into permanent epidermis. Since then, over 900 patients with severe burns have successfully received autologous skin grafts using this technology. More recently, we demonstrated that ex vivo cell therapy can be used to repair articular cartilage defects of the knee (5, 6). This technology involves the processing and cultivation of an autologous cartilage biopsy into a therapeutically effective implant.
