Tissue Banking and Progenitor Cells

Sources of Tissue

Tissues used for transplantation come from two primary sources: living donors and deceased donors. Living donors may be individuals who donate for their own use (autologous HPCs or sperm), as directed donors for a given individual (allogeneic HPCs or sperm donation), or altruistically for unknown recipients (surgical discard bone, sperm donation, allogeneic HPCs). A large majority of bone, skin, and cardiac valves used for transplantation, as well as eye tissue, come from deceased donors. Unlike solid-organ donation, where there is a need for the organs to be obtained while circulation is maintained, deceased donor tissue can be obtained for several hours after death and up to 24 hours later if the body is refrigerated. This substantially increases the number of available tissue donors. Because corneal tissue has minimal contact with the circulatory system, some individuals who would otherwise be excluded as tissue donors may still be eye donors.

Deceased donor tissue is procured primarily from hospital operating rooms or morgues and medical examiners’ offices. Harvesting of tissue is performed in a sterile or clean environment using aseptic techniques. Many tissues, such as bone, are then frozen for subsequent processing and refreezing or freeze-drying. Specialized tissues such as cornea are processed immediately and stored for only a short time (48–72 hours) before use. Tissue from living donors is procured in the operating room (surgically salvaged bone or bone marrow) or in specialized clean environments that apheresis centers and sperm banks are equipped to provide. These tissues are collected under sterile conditions, processed immediately, and either used within 24 hours or frozen for subsequent use.

Tissue Bank Activities

The major activities of tissue banks are outlined in Box 39.2 . A major impetus for the movement to formal, accredited tissue banks was the concern about transfusion-transmitted disease. As with blood banks and transfusion services (see Chapter 37, Chapter 38 ), donor recruitment, screening, and testing are critical functions of the tissue bank. Since the early 1990s, cases involving disease transmission documented that careful screening by both review of the medical record and serologic testing, as well as maintenance of detailed records, was critical to safe tissue banking practices and, thus, acceptance of allograft tissue by both the public and health care providers. The Joint Commission (TJC) has standards for tissue banking practices that are targeted primarily at the transplantation facility. These standards focus on the necessity for implantation facilities to keep clear, precise records regarding tissue receipt, storage, and use so that all allogeneic tissues can be traced from donor to recipient. TJC standards also require institutions to establish a mechanism for physicians to report adverse reactions and the originating tissue bank to be notified. Accredited full-service tissue banks, in the same manner as blood banks, investigate suspected reactions or complications extensively. “Look-back” reviews should include reviews of the complications associated with other tissue from the same donor; the current health of the donor, if living; and quarantining of other tissue from the same donor. The American Association of Tissue Banks (AATB) provides strict standards and accreditation for organizations involved in any area of tissue banking. Several states also require tissue banks to be licensed, and the U.S. Food and Drug Administration (FDA) regulates the screening, processing, and storage of donor tissue used for transplantation purposes ( ).