Human Tissue Transplants

by Food and Drug Administration (FDA)

For millions of Americans, human tissue transplants represent a modern miracle.

These bits of donated eye, skeleton, skin, muscle, sperm, and other reusable body tissues can restore sight or repair injured knees and ankles. They can help mend a burn victim or renew a cancer patient's lost bone. They can even replace a failing heart valve or allow an infertile couple to have children.

But like blood and other body fluids, these living materials also can transmit disease — including HIV (the virus that causes AIDS) and two types of viral hepatitis. Concern over this potential is fueling increased FDA oversight of the human tissue industry, which provides products for an estimated 300,000 transplants a year in the United States.

FDA and industry experts say the chance of actually passing disease through transplants appears small. They emphasize that patients should not decline a needed transplant for fear of acquiring a disease. Industry organizations, they say, have made notable efforts to oversee tissue bank products.

Industry Checks Itself

For years, without extensive federal controls, large segments of the domestic human-tissue industry have self-regulated the quality and commerce of products through voluntary compliance with industry standards. For example, trade groups such as the American Association of Tissue Banks (AATB) and the Eye Bank Association of America (EBAA) sponsor voluntary accreditation programs requiring periodic inspections and adherence to standards.

FDA estimates that more than 100 of the 150 to 200 U.S. tissue banks are accredited by AATB or are undergoing accreditation. Of EBAA's member banks, which are responsible for providing tens of thousands of corneas annually, 95 percent are accredited. The American Fertility Society accredits some reproductive tissue banks. The American Red Cross, a major supplier of human tissue, uses AATB guidelines. In addition, five states — California, Florida, Georgia, Maryland, and New York — require licensing of tissue bank facilities.

In May, the national Centers for Disease Control and Prevention published new guidelines for preventing HIV transmission in tissue and organ transplants. CDCœs guidance now includes detailed instructions concerning issues such as donor screening and testing, donor exclusion criteria, inactivation of infectious organisms, and recall of tissues found to be contaminated.

Since 1985, U.S. doctors have performed 1 million tissue transplant operations, according to CDC estimates. In all these cases, only two tissue donors are known to have transmitted AIDS to recipients. (Other diseases, such as hepatitis and rabies, have been transmitted through transplants, though the incidence is extremely low.)

Both AIDS transmission cases occurred in the mid-1980s, during the early days of the AIDS epidemic, when tests for the virus were less sophisticated.

One incident involved transfer of a small amount of bone tissue from an HIV-positive donor, which infected a recipient. The other episode came to light three years ago. A reputable Virginia tissue bank, LifeNet Transplant Services, had stored 61 organs and tissue grafts taken from a man in 1985 after he died of gunshot wounds. Before removing organs and tissue, the bank twice analyzed the donor's blood for infectious disease. In both instances the blood tested negative. But in 1991, through retrospective analysis using more refined methods, the tissue bank discovered that the donor's blood tested positive for HIV.

The bank immediately set out to find and test recipients. Due to poor record keeping by hospitals and practitioners, LifeNet could locate only 34 of more than 40 patients who received the infected organs or tissue. Seven of these persons are known to have contracted the AIDS virus, and three have died.

FDA Tightens Controls

Concerns that disease transmission, though rare, can occur, coupled with new information gleaned from an FDA investigation into imported human tissue, have prompted FDA to impose controls on tissue banking and has set the stage for possible congressional action. In December 1993, FDA imposed interim rules that make most banked human tissue — including bone, ligaments, tendons, fascia (muscle-enclosure tissue), cartilage, corneas, and skin — subject to some of the same kinds of scrutiny for infectious agents now applied to the nation's blood supply.

The rules do not cover transplants of organs such as the heart and liver, which are managed under separate programs in the federal Health Care Financing Administration and Health Resources and Services Administration. Other tissue products fall under existing regulations and are exempt from the new rules. For example, bone marrow transplants are managed by the National Institutes of Health. Dura mater (brain membrane material), heart valve allografts, and corneal lenticules are regulated by FDA under the Medical Device Amendments of 1976.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.