No abstract

PARV4 and PARV5 are readily detected in manufacturing plasma pools, test pools (constructed from 16 donations), and individual donations derived from healthy blood donors. The prevalence of these viruses was increased in plasma samples from febrile patients. Despite the use of highly sensitive assays for HBoV, it was not possible to identify manufacturing plasma pools containing HBoV sequences.

We report a novel parvovirus (PARV4) and related variants in pooled human plasma used in the manufacture of plasma-derived medical products. Viral DNA was detected by using highly selective polymerase chain reaction assays; 5% of pools tested positive, and amounts of DNA ranged from <500 copies/mL to >106 copies/mL plasma.

Variability in the performance of nucleic acid amplification technology (NAT)-based assays presents a significant problem in the diagnosis and management of human cytomegalovirus (HCMV) infections. Here we describe a collaborative study to evaluate the suitability of candidate reference materials to harmonize HCMV viral load measurements in a wide range of NAT assays. Candidate materials comprised lyophilized Merlin virus, liquid Merlin virus, liquid AD169 virus, and purified HCMV Merlin DNA cloned into a bacterial artificial chromosome. Variability in the laboratory mean HCMV concentrations determined for virus samples across the different assays was 2 log10. Variability for the purified DNA sample was higher (>3 log10). The agreement between laboratories was markedly improved when the potencies of the liquid virus samples were expressed relative to the lyophilized virus candidate. In contrast, the agreement between laboratories for the purified DNA sample was not improved. Results indicated the suitability of the lyophilized Merlin virus preparation as the 1st WHO International Standard for HCMV for NAT. It was established in October 2010, with an assigned potency of 5 × 10(6) International Units (IU) (NIBSC code 09/162). It is intended to be used to calibrate secondary references, used in HCMV NAT assays, in IU.

Improving short-term results with intestine transplantation have allowed more patients to benefit with nearly 700 patients alive in the United States with a functioning allograft at the end of 2007. This success has led to an increase in demand. Time to transplant and waiting list mortality have significantly improved over the decade, but mortality remains high, especially for infants and adults with concomitant liver failure. The approximately 200 intestines recovered annually from deceased donors represent less than 3% of donors who have at least one organ recovered. Consent practice varies widely by OPTN region. Opportunities for improving intestine recovery and utilization include improving consent rates and standardizing donor selection criteria. One-year patient and intestine graft survival is 89% and 79% for intestineonly recipients and 72% and 69% for liver-intestine recipients, respectively. By 10 years, patient and intestine survival falls to 46% and 29% for intestine-only recipients, and 42% and 39% for liver-intestine, respectively.Immunosuppression practice employs peri-operative antibody induction therapy in 60% of cases; acute rejection is reported in 30%-40% of recipients at one year. Data on long-term nutritional outcomes and morbidities are limited, while the cause and therapy for late graft loss from chronic rejection are areas of ongoing investigation.

The variability in CMV DNA results reported on individual samples has been reduced by the IS, but ongoing clinically relevant variability persists, preventing meaningful interassay result comparison.

In human medicine, human cytomegalovirus (HCMV) is readily transmitted by organ transplant causing end-organ disease and triggering graft rejection in recipients. Because of a chronic shortage of human organs, pigs transgenic for human complement control proteins are being considered as potential donors. Such xenotransplantation raises concerns about the potential zoonotic transmission of viruses including porcine cytomegalovirus (PCMV), an endemic infection of pigs. Similar to HCMV and PCMV transmission is thought to occur in utero and perinatally. We used quantitative polymerase chain reaction to examine the prevalence, organ distribution and viral load of PCMV in human decay accelerating factor (CD55) transgenic pigs. In animals reared under conventional farm conditions, virus was identified in a wide range of organs including potential xenografts (liver, kidney and heart). The spleen was PCMV DNA positive in all infected pigs. Examination of foetal spleens failed to identify evidence of transplacental infection and prospective monitoring of two litters showed that infection occurred in the postnatal period. This transmission was prevented by hysterotomy derivation and barrier rearing. Our findings demonstrate that PCMV could be eradicated from pig herds being bred for xenotransplantation and argue that the spleen from donor animals should be examined as part of quality control procedures if clinical trials proceed.

Quantitative detection of cytomegalovirus (CMV) DNA has become a standard part of care for many groups of immunocompromised patients; recent development of the first WHO international standard for human CMV DNA has raised hopes of reducing interlaboratory variability of results. Commutability of reference material has been shown to be necessary if such material is to reduce variability among laboratories. Here we evaluated the commutability of the WHO standard using 10 different real-time quantitative CMV PCR assays run by eight different laboratories. Test panels, including aliquots of 50 patient samples (40 positive samples and 10 negative samples) and lyophilized CMV standard, were run, with each testing center using its own quantitative calibrators, reagents, and nucleic acid extraction methods. Commutability was assessed both on a pairwise basis and over the entire group of assays, using linear regression and correspondence analyses. Commutability of the WHO material differed among the tests that were evaluated, and these differences appeared to vary depending on the method of statistical analysis used and the cohort of assays included in the analysis. Depending on the methodology used, the WHO material showed poor or absent commutability with up to 50% of assays. Determination of commutability may require a multifaceted approach; the lack of commutability seen when using the WHO standard with several of the assays here suggests that further work is needed to bring us toward true consensus. Q uantitative detection of cytomegalovirus (CMV) DNA has become a standard part of care for many groups of immunocompromised patients, but particularly for transplant recipients (1-4). A host of laboratory-developed real-time PCR methods have been described for this purpose, and more recently, FDAapproved assays have become available. The benefits of such testing to trigger preemptive or therapeutic treatments or to monitor the efficacy of such treatments and determine therapeutic endpoints are widely accepted. However, benchmark values for such interventions have yet to be established, and it is now decades after the introduction of molecular diagnostics. The reasons for this lack of consensus have become clear over a number of studies which have shown poor quantitative concordance between laboratories and between methods. Several investigators have documented discordant results for human cytomegalovirus (HCMV) testing as well as for other viral load measures that depend largely upon methods developed in the laboratory (5-7). The reasons for such variability may be numerous (8); however, intuitively, different quantitative calibrators may directly relate to different quantitative results. This has been confirmed in the literature, and the importance of developing consensus standards has been well accepted (9-11) and confirmed by past experience with other viruses.The advent of the first WHO International Standard for HCMV DNA was meant to address this need (12). This material consists of a known quantity of the CMV merl...