Organ donor screening using parallel nucleic acid testing allows assessment of transmission risk and assay results in real time

Expansion of the donor pool may lead to utilization of donors with risk factors for viral infections. Donor laboratory screening relies on serological and nucleic acid testing (NAT). The increased sensitivity of NAT in low prevalence populations may result in false‐positive results (FPR) and may cause unnecessary discard of organs.We developed a screening algorithm to deal, in real time, with potential FPR. Three NAT assays: COBAS AmpliScreen assay (CAS), AmpliPrep Total Nucleic Acid Isolation/CAS, and AmpliPrep/TaqMan assays, were validated and used in parallel for prospective screening of increased‐risk donors (IRD), and the probability of FPR was calculated. The lower limit of detection of this algorithm was 9.79, 21.02, and 4.31 IU/mL for human immunodeficiency virus‐1, hepatitis C virus, and hepatitis B virus, respectively, with an average turn‐around‐time of 7.67 h from sample receipt to result reporting. The probability that a donor is potentially infectious with two NAT concordant results was >90%. NAT screening of 35 IRD within 18 months resulted in transplantation of 102 additional organs that without screening would either not be used or used with restrictions in Australia. Using a parallel testing algorithm, real‐time confirmation of seropositive donors allows use of organs from IRD and safer expansion of the donor pool.     

Donor derived hepatitis B virus infection: Analysis of the Organ Procurement & Transplantation Network/United Network for Organ Sharing Ad Hoc Disease Transmission Advisory Committee

Hepatitis B virus (HBV) can be transmitted from organ donor to recipient, but details of transmission events are not widely published. The Disease Transmission Advisory Committee (DTAC) evaluated 105 cases of potential donor derived transmission events of HBV between 2009‐2017. Proven, probable or possible transmission of HBV occurred in 25 (23.8%) cases. Recipients of liver grafts were most commonly infected (20 of 21 exposed recipients) compared to 9 of 21 exposed non‐hepatic recipients. Eleven of 25 donors were HBV core antibody (HBcAb) positive/HBV surface antigen (HBsAg) negative and infected 8/20 recipients. Of the 10 liver recipients and 1 liver‐kidney recipient who received organs from these donors: six were not given antiviral prophylaxis, two developed infection after antiviral prophylaxis was discontinued, two developed HBV while on lamivudine prophylaxis, one was on antiviral prophylaxis and did not develop HBV viremia or antigenemia. One recipient of a HBcAb positive/HBsAg negative kidney developed active HBV infection. Unexpected donor‐derived transmission of HBV was a rare event in reports to DTAC, but was often detected in the recipient late post‐transplant. Six of 11 recipients (54.5%) of a liver from a HBcAb positive donor did not receive prophylaxis; all of these were potentially preventable with the use of anti‐viral prophylaxis.     

Communication gaps for solid organ transplant‐transmitted infections among infectious disease physicians: an Emerging Infections Network survey

Infectious disease (ID) physicians were surveyed concerning knowledge and management of potential transplant‐transmitted infections (TTIs). On the basis of cumulative responses to 4 questions that assessed solid organ transplant‐related clinical exposures and experience, respondents were divided into 3 groups: most, some, or little transplant experience. Rapid access to donor data was identified as the most important factor when evaluating a potential TTI. Despite varying experience in transplant infections, ID physicians are frequently asked for opinions regarding donor suitability and TTI management. Improved ID physician access to donor information and educational resources will allow more optimal management of potential TTIs.     

Sensitivity of individual donor nucleic acid testing (NAT) for the detection of hepatitis B infection by studying diluted NAT yield samples

BackgroundScreening blood donors for the presence of hepatitis B virus surface antigen (HBsAg) has been the backbone of blood safety. However, occult hepatitis B infection (OBI) in donors can be missed when only HBsAg screening is used. Nucleic acid testing (NAT) is capable of detecting OBI among donors. The aim of our study was to analyse the sensitivity of NAT for detecting OBI.ResultsOf the 18 samples studied, nine were NAT-reactive at a dilution of <1:4 and five out of these showed presence of antibody to core antigen (IgG+IgM). Antibody to surface antigen was present in only two of the nine NAT-reactive samples, one with antibody to core antigen and the other without. Six had a viral load in the range from <10 to 38 IU/mL whereas the viral load in the remaining three samples was not determined. Among the other nine samples which were NAT-reactive at dilutions ≥1:4, antibody to core antigen (IgG+IgM) was present in seven.DiscussionOur study showed that ID-NAT testing along with HBsAg screening could detect most potentially HBV infectious donors (including those with OBI). NAT screening for HBV on diluted samples could compromise blood safety because samples with a low viral load will escape detection.     

Hepatitis B core antibody‐positive donors in cardiac transplantation: a single‐center experience

Hepatitis B virus (HBV) core antibody (HBcAb)‐positive donors are increasingly utilized in solid organ transplantation. We report a single center's experience in cardiac transplantation with 18 HBcAb‐positive donors. Available follow‐up on recipients of cardiac allografts from HBcAb‐positive donors, including 2 donors with low‐level serum HBV DNA at the time of transplantation, demonstrated no documented donor‐derived HBV transmission.     

Successful treatment of donor‐derived hepatitis C viral infection in three transplant recipients from a donor at increased risk for bloodborne pathogens

We report here the successful treatment of hepatitis C virus (HCV) transmitted from a nucleic acid testing (NAT)‐negative donor to three HCV‐negative recipients—two renal transplants and one liver. Both renal recipients underwent standard deceased‐donor renal transplantation with immediate graft function. The liver recipient underwent standard orthotopic liver transplantation and recovered uneventfully. The donor was a 39‐year‐old woman with a terminal serum creatinine of 0.7 mg/dL. She was high risk for bloodborne pathogens, based upon a history of sexual contact with an HCV‐infected male partner. Recipient 1 was a 45‐year‐old man with a history of end‐stage renal disease from systemic lupus erythematosus. Recipient 2 was a 62‐year‐old woman with a history of end‐stage renal disease caused by hypertension and insulin‐dependent diabetes. Recipient 3 was a 42‐year‐old man with acute liver failure from acetaminophen ingestion. All recipients became HCV polymerase chain reaction positive on post‐transplant follow‐up. Both kidney recipients were treated with ledipasvir/sofosbuvir combination therapy for 12 weeks without side effects or rejection episodes. Recipient 3 was treated with ledipasvir/sofosbuvir in combination with ribavirin for 12 weeks without side effects. All patients achieved a sustained viral response at 12 weeks and are considered cured of HCV. The kidney recipients maintained good allograft function with a serum creatinine of 1.4 mg/dL and 1.0 mg/dL, respectively. Both renal recipients maintained normal liver function post treatment and did not develop any evidence of fibrosis. The liver recipient's liver function tests returned to normal without further incident. This case report provides evidence for the successful treatment of donor‐derived HCV in transplant recipients.     

HIV co‐infection is associated with increased transmission risk in patients with chronic hepatitis C virus

Molecular epidemiological analysis of viral pathogens can identify factors associated with increased transmission risk. We investigated the frequency of genetic clustering in a large data set of NS34A, NS5A, and NS5B viral sequences from patients with chronic hepatitis C virus (HCV). Within a subset of patients with longitudinal samples, Receiver Operator Characteristic (ROC) analysis was applied which identified a threshold of 0.02 substitutions/site as most appropriate for clustering. From the 7457 patients with chronic HCV infection included in this analysis, we inferred 256 clusters comprising 541 patients (7.3%). We found that HCV/HIV co‐infection, young age, and high HCV viral load were all associated with increased clustering frequency, an indicator of increased transmission risk. In light of previous work on HCV/HIV co‐infection in acute HCV cohorts, our results suggest that patients with HCV/HIV co‐infection may disproportionately be the source of new HCV infections and treatment efforts should be geared towards viral elimination in this vulnerable population.     

Current practices and evaluation of screening solid organ donors for West Nile virus

The first cases of West Nile virus (WNV) transmitted through solid organ transplantation (SOT) were identified in 2002. Subsequently, 5 additional clusters have been reported to public health officials in the United States. Based upon a limited number of known cases, patients who acquire WNV from infected donor organs might be at higher risk for severe neurologic disease and death, compared with patients infected through mosquito bites. In response, some organ procurement organizations (OPOs) have instituted pre‐transplant screening of organ donors for WNV infection. We evaluated the current practices, concerns, and challenges related to screening organ donors for WNV in the United States by reviewing the relevant medical literature and interviewing key stakeholders. Screening organ donors for WNV is not required by national policy. In 2008, 11 (19%) of 58 OPOs performed WNV screening using nucleic acid amplification testing (NAT). These OPOs differ in their screening strategies, NAT performed, and logistical challenges. Concerns of delays in receiving NAT results before transplant and potential false‐positive results leading to organ wasting are limitations to more widespread screening. Furthermore, it is unknown if WNV screening practices decrease SOT‐related morbidity and mortality, or if screening is cost‐effective. Additional data are needed to assess and improve transplant outcomes related to WNV.