How donor selection criteria can be evaluated with limited scientific evidence: lessons learned from the TRANSPOSE project.

BACKGROUND AND OBJECTIVE: Donor selection criteria (DSC) are a vital link in the chain of supply of Substances of Human Origin (SoHO) but are also subject to controversy and differences of opinion. Traditionally, DSC have been based on application of the precautionary principle. MATERIALS AND METHODS: From 2017 to 2020, TRANSPOSE (TRANSfusion and transplantation PrOtection and SElection of donors), a European research project, aimed to identify discrepancies between current DSC by proposing a standardized risk assessment method for all SoHO (solid organs excluded) and all levels of evidence. RESULTS: The current DSC were assessed using a modified risk assessment method based on the Alliance of Blood Operators' Risk-based decision-making framework for blood safety. It was found that with limited or diverging scientific evidence, it was difficult to reach consensus and an international standardized method for decision-making was lacking. Furthermore, participants found it hard to disregard their local guidelines when providing expert opinion, which resulted in substantial influence on the consensus-based decision-making process. CONCLUSIONS: While the field of donation-safety research is expanding rapidly, there is an urgent need to formalize the decision-making process regarding DSC. This includes the need for standardized methods to increase transparency in the international decision-making process and to ensure that this is performed consistently. Our framework provides an easy-to-implement approach for standardizing risk assessments, especially in the context of limited scientific evidence.

Putting the spotlight on donation-related risks and donor safety - are we succeeding in protecting donors?

BACKGROUND AND OBJECTIVE: The European consortium project TRANSPOSE (TRANSfusion and transplantation: PrOtection and SElection of donors) aimed to assess and evaluate the risks to donors of Substances of Human Origin (SoHO), and to identify gaps between current donor vigilance systems and perceived risks. MATERIALS AND METHODS: National and local data from participating organizations on serious and non-serious adverse reactions in donors were collected from 2014 to 2017. Following this, a survey was performed among participants to identify risks not included in the data sets. Finally, participants rated the risks according to severity, level of evidence and prevalence. RESULTS: Significant discrepancies between anticipated donor risks and the collected data were found. Furthermore, many participants reported that national data on adverse reactions in donors of stem cells, gametes, embryos and tissues were not routinely collected and/or available. CONCLUSIONS: These findings indicate that there is a need to further develop and standardize donor vigilance in Europe and to include long-term risks to donors, which are currently underreported, ensuring donor health and securing the future supply of SoHO.

The BD BACTEC FX blood culture system with the gentlemacs dissociator is suitable for sterility testing of heart valve and vascular allografts-A validation study.

To present our validation study of the BD BACTEC FX blood culture system for sterility testing of cardiovascular tissues aimed for human application. For operational qualification, we performed temperature mapping of the system, vacuum test using non-inoculated BACTEC vials, and growth promotion tests by injecting contaminant strains into aerobic and anaerobic bottles. For performance qualification, negative control, assessment of method suitability, evaluation of sensitivity limits, control of neutralization of antibiotics in biopsy samples from allografts and tissue toxicity effects, were performed. Tissue samples and transport/cryopreservation solutions were homogenized in GentleMACS Dissociator and injected into BACTEC Plus aerobic and anaerobic vials for incubation at 35 °C for 14 days. Tissues were spiked with aerobic and anaerobic bacteria and fungi. Growth of contaminants appeared in all aerobic and anaerobic vials for Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa; in anaerobic vials for Cutibacterium (Propionibacterium) acnes and Clostridium sporogenes; and only in aerobic vials for Candida albicans and Aspergillus brasiliensis. The majority of bacterial strains were detected within two days (59-100%), exceptionally between 3 and 14 days. In contrast, fungal contaminations were detected within 2, 3-6, 7-10 and after 10 days of incubation in 33.3, 71.6, 96.6 and 99.9% of cases,respectively. Uninhibited growth appeared in the tissue biopsies and homogenized tissues with and without antibiotics and in other solutions. BD BACTEC blood culture system with GentleMACS Dissociator is a rapid and efficient tool for detection of contamination in cardio-vascular tissues aimed for human application.

Significant variation in heart valve banking practice.

The European Blood Alliance (EBA) Tissue and Cells annual benchmarking exercise identified that in 2014, the heart valve (HV) discard rate in tissue establishments (TEs) run by EBA members was between 19 and 65%. Given this significant discard rate, a decision was taken to carry out a worldwide data-gathering exercise to assess the processing methodology in different TEs. In collaboration with the Foundation of European Tissue Banks, a questionnaire asking for the details on HV processing was sent to TEs worldwide. Nineteen questionnaires were received back from 15 European TEs and 4 non-European TEs. The data provided confirmed a significant discard rate of HVs with 43-50% of aortic valves and 20-32% of pulmonary valves being discarded in 2015. The causes of HV discard varied, with microbiology contamination, anatomical and medical reasons being the main causes. This data-gathering exercise highlighted significant variations in practice in different TEs including how donor suitability is assessed, critical timings for heart retrieval and processing, heart rinsing, HV decontamination protocols and methods of microbiological testing. To reduce the discard rates, there are several aspects of HV banking that could be validated and standardised. Here, we report the findings of this data-gathering exercise. We consider this a first step that will help lead to standardising HV banking.

Validation of microbiological testing in cardiovascular tissue establishments: results of a second international quality-round trial.

The performance of many laboratories can be evaluated by participation in external quality assessment (EQA) schemes. EQA allows for comparison of a laboratory's performance with a source outside the laboratory-either a peer group of laboratories or a reference laboratory. Such EQA schemes do not exist in tissue banking despite the fact that tissue establishments (TE) perform very complex procedures. This paper describes the first ever EQA scheme in the field specifically assessing microbiological aspects in heart valve (HV) banking. Twenty-two TEs participated. Three HV tissue samples were sent to each participating TE-two contaminated with non-pathogenic micro-organisms and a third negative control. The aims were to isolate and identify the micro-organisms present and then to successfully decontaminate the HV tissue using the routine standard operating procedures of the TE. Eight of the TEs were able to isolate and identify all contaminating micro-organisms present, and of these, five also successfully decontaminated the tissue; 13 TEs failed to establish the identity of one or more of the contaminants; five TEs appear to have introduced contamination during the processing or testing of the tissue; and eight failed to successfully decontaminate the HV tissue. This initiative provides TEs with an international benchmark for tissue product microbiology testing. It has identified significant variation in practice and in the ability of different TEs to identify the presence of contamination. There is now work ongoing with the aim of setting up a regular EQA scheme for HV banking.

Microparticles, malignancy and thrombosis.

Microparticles (MPs) are considered to be important biological effectors of several different physiological and pathological processes. There is increasing evidence of their role in haemostasis and thrombosis, and also of their importance in cancer cell survival, invasiveness and metastasis. The level of circulating MPs has been assessed in many different disease states, and there are reports that patients with malignancy and patients with thrombosis have increased levels of circulating MPs and MP-dependent thrombogenic potential. Research into the function and effect of MPs is currently hampered by a lack of standardization in the methods used to identify and quantify them. As these methods improve it is likely that MP assays will be of use both diagnostically and therapeutically in the future.

Rapid GMP-Compliant Expansion of SARS-CoV-2-Specific T Cells From Convalescent Donors for Use as an Allogeneic Cell Therapy for COVID-19.

COVID-19 disease caused by the SARS-CoV-2 virus is characterized by dysregulation of effector T cells and accumulation of exhausted T cells. T cell responses to viruses can be corrected by adoptive cellular therapy using donor-derived virus-specific T cells. One approach is the establishment of banks of HLA-typed virus-specific T cells for rapid deployment to patients. Here we show that SARS-CoV-2-exposed blood donations contain CD4 and CD8 memory T cells which recognize SARS-CoV-2 spike, nucleocapsid and membrane antigens. Peptides of these antigens can be used to isolate virus-specific T cells in a GMP-compliant process. The isolated T cells can be rapidly expanded using GMP-compliant reagents for use as an allogeneic therapy. Memory and effector phenotypes are present in the selected virus-specific T cells, but our method rapidly expands the desirable central memory phenotype. A manufacturing yield ranging from 1010 to 1011 T cells can be obtained within 21 days culture. Thus, multiple therapeutic doses of virus-specific T cells can be rapidly generated from convalescent donors for potential treatment of COVID-19 patients.