Tissue Services Director Margery Moogk

In our last issue of Resource, we focused on reports of infection transmission through tissue transplants. In this issue, I thought it would be appropriate to review disease transmission and what we are doing to prevent it.

Several recent high-profile news stories dealing most often with organ transplantation issues have raised concerns about disease transmission and transplant safety. The topics include the tragic death of an organ recipient resulting from mismatched blood types, the transmission of West Nile virus and melanoma by organ transplantation, and the transmission of hepatitis C by both organ and tissue transplants. In addition, the wide publicity given to Creutzfeldt-Jakob disease has raised questions about the possibility of contracting it from tissue transplants.

First, let me say I remain confident that disease transmission from tissue transplants is an extremely unlikely outcome. As both local and worldwide health concerns evolve, the Tissue Services continues to react quickly and prudently to protect patient safety. It is important to note that none of these transmissions has involved the Northwest Tissue Services and only one has involved tissue transplants at all.

Since it began operating 15 years ago, the Tissue Services has worked continually to improve and update policies and procedures to protect transplant recipients. We can react very quickly to new information, modifying our practices even before new industry standards are instituted. Regularly reviewing our protocols in light of ongoing public health findings and technological advances gives us confidence that we are providing a high level of safety and quality and a very low level of risk to transplant recipients.

“Even as worldwide public health concerns continue to evolve, we have and will continue to respond quickly and appropriately, with patient safety as our foremost concern.”

Two key elements in our procedures play an especially important role in protecting against risk from new or evolving public health concerns. First is our extensive medical and social history screening. Trained coordinators interview donor family members and healthcare providers, asking about many conditions, including cancers and autoimmune and neurological diseases, which would rule out donation. Donors are also assessed for evidence of current infection of any kind. Secondly, trained tissue technologists perform careful physical assessments of donors before procurement, looking for any signs of disease.

Additionally, we rely on a broad safety net to monitor our activities for compliance and to safeguard against the possibility of human error. Our Quality Assurance Department, which does not participate in procuring or processing allograft tissue, provides a vital check on every aspect of our operations. This is especially important in evaluating a donor’s suitability.

Before tissue is released for distribution, Tissue Services donation specialists compile and assess serological testing results, medical and social screening, medical records, autopsy and pathology reports, and microbiological testing results on each quarantined allograft. Then independent quality assurance staff carefully evaluates the donor’s chart before it is presented to the medical director for final approval. Double-checking others’ work is an important step toward eliminating the possibility of human error.

In the context of our built-in and evolving precautions, let’s take a look at each of these public health issues and their implications for the safety of tissue transplant recipients.

Focusing on critical steps to prevent errors
Perhaps the most highly publicized recent case is the tragic death of a young heart-lung recipient who received blood-type-incompatible organs. According to published reports, both the surgeon and transplant coordinator involved in decision-making assumed the other party had confirmed a match between donor and recipient. This misunderstanding underscores the importance of performing risk assessments to identify the critical steps in procurement and transplantation decision-making where the risk of human error is highest and the consequences most serious. Procedures must be in place to crosscheck and confirm decisions before moving to the next step in transplant protocols.

Newer, more accurate tests
Another widely publicized donation-related disease transmission case involved the transmission of hepatitis C from an Oregon man. His blood tested non-reactive to the virus at the time he donated organs, corneas, and tissues, because he was in the 8 to 10-week “window period” prior to seroconversion. According to the Morbidity and Mortality Weekly Report (MMWR 2003, 52:273-276), three organ recipients definitely contracted the disease from their transplants. Only one, a kidney recipient, remains alive. The role of the hepatitis C virus in the deaths of the other organ recipients remains unclear.

Even though the lung recipient was diagnosed with hepatitis C about a year after her transplant, the information was not relayed to the tissue bank. Had they been notified they would have discontinued the release of tissues from the donor. Not until a tendon recipient showed acute symptoms of hepatitis C six weeks following her surgery did the tissue bank learn of the donor’s status. Of the 32 tissue recipients, 5 have probably contracted hepatitis C as a result of their transplants. The remaining 44 tissues have been recalled.

When the archived sample of the donor’s blood was tested with a newer test of viral genetic material (RNA) that can detect infection at an earlier stage, it tested positive. The newer nucleic acid testing (NAT) is not yet approved for screening tissue donors; however we anticipate that it will soon be approved for that use.

The New England Journal of Medicine recently reported the case of two kidney recipients who apparently contracted melanoma from a donor who had been treated for it, even though the donor had been cancer-free for 16 years before she died. Investigators believe that the melanoma was transmitted by the organs, because both recipients’ initial cancers were highly unusual: neither recipient had a primary melanoma tumor site, but only secondary tumors. One investigator believes that while the tumor cells lay dormant in the donor’s kidneys, the transplant recipients’ regime of immunosuppresant drugs allowed them to proliferate.

The criteria for accepting tissue donors are in many instances stricter than for organ donors because there are almost always alternatives for the transplants we provide. The overwhelming demand for life-saving organs justifies tolerating a greater level of uncertainty.

Added precautions
The Tissue Services has recently strengthened criteria to prevent possible transmission of new variant Creutzfeldt-Jakob disease (vCJD), often referred to as mad-cow disease. We have implemented an expanded review of each potential donor’s travel history and exclude those who spent extended periods in areas of higher risk for vCJD, primarily in Europe and the United Kingdom. These are the same restrictions that are now in place for blood donors. To date, there has been no evidence of vCJD transmission even by blood transfusion.

Another area of concern is the West Nile virus, which has been transmitted by blood transfusions and organ transplants. There have been no reported cases to date of tissue transplants transmitting the virus. For most of the population, West Nile virus is nothing more than the flu, but the virus poses a greater risk for organ recipients.

In some cases, West Nile virus leads to viral encephalitis. Our screening process eliminates potential donors with symptoms of viral encephalitis. West Nile virus often produces rashes, which, again, would be discovered during the physical assessment process.

Even as worldwide public health concerns continue to evolve, we have and will continue to respond quickly and appropriately, with patient safety as our foremost concern.