Use of HCV-infected Organs in Solid Organ Transplantation

An Ethical Challenge But Plausible Option

Gayatri Nangia; Kelly Borges; K. Rajender Reddy

Disclosures

J Viral Hepat. 2019;26(12):1362-1371. 

In This Article

Testing and Categorizing HCV-positive Organs

While there are no regulations regarding HCV-positive organ donors, in August of 2015, the United Network for Organ Sharing (UNOS) mandated HCV nucleic acid testing (NAT) in addition to the existing anti-HCV testing in donors.[16] The addition of this test helps to delineate the varying levels of risk that HCV-positive organs present. Serologic testing (eg enzyme immunoassays) detects HCV antibodies (anti-HCV) 2–6 months after exposure and is used to detect past or present exposure to HCV. This test alone is not ideal because it cannot differentiate between active and resolved infection.[17] NAT, on the other hand, can detect HCV ribonucleic acid (RNA) 5–7 days after exposure using polymerase chain reaction (PCR), branched DNA signal amplification and transcription-mediated amplification (TMA).[17] Therefore, NAT testing is optimal for determining whether active HCV infection is present.[17] Using both anti-HCV and NAT testing, it is possible to categorize the relative risk of transmission from HCV-positive organs (Table 1). Organ donors that test positive for both HCV antibodies and HCV RNA (anti–HCV-positive, NAT-positive) have active HCV infection and are at a high risk for transmission. In order to convey that these organs are high risk, these donors should be categorized as anti–HCV-positive, viremic donors.[1] Donors who are negative for the presence of HCV antibodies but are positive for HCV RNA (anti–HCV-negative, NAT-positive) have acute HCV infection in the 'window period' and also present a high risk of transmission.[1] Since it may take up to 60–70 days for HCV antibodies to become detectable in the blood, the 'window period' is defined as the period of time after exposure to the virus and before antibodies can be detected.[1] While there is a possibility of a false-positive NAT test, the risk is low.[1] Data from blood donors show the rate of false-positive NAT tests risk to be as low as 0.1%-0.8%.[18,19] Furthermore, unpublished data from 2010 to 2013 estimate an even lower rate of <0.02% in deceased organ donors.[1] Lastly, donors that test positive for the presence of HCV antibodies but negative for the presence of HCV RNA (anti–HCV-positive, NAT-negative) have either cleared their HCV infection, been treated for HCV infection, or are false-positive for HCV antibodies.[1] These donors present with a low to intermediate risk of transmission, depending on the donor's age, gender, recent history of IV drug use and the timing of the NAT test.[1] Before universal NAT testing was implemented, donors were not tested for HCV viremia and therefore the relative risks associated with transplanting HCV-positive organs were not distinguished. Therefore, we use the term HCV-positive to mean HCV antibody positive with or without viremia and the term HCV-infected as synonymous with HCV-NAT positive.

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