Inactivation of a broad spectrum of viruses and parasites by photochemical treatment of plasma and platelets using amotosalen and ultraviolet A light

Introduction of 7-day amotosalen/ultraviolet A light pathogen-reduced platelets in Honduras: Impact on platelet availability in a lower middle-income country

BACKGROUND AND OBJECTIVES

Honduras became the first lower middle-income country (LMIC) to adopt amotosalen/UVA pathogen-reduced (PR) platelet concentrates (PCs) as a national platelet safety measure in 2018. The Honduran Red Cross (HRC) produces ~70% of the national platelet supply using the platelet-rich plasma (PRP) method. Between 2015 and 2018, PCs were screened with bacterial culture and issued as individual, non-pooled PRP units with weight-based dosing and 5-day shelf-life. PR PCs were produced in six-PRP pools with a standardized dose (≥3.0 × 1011), no bacterial screening and 7-day shelf-life. Gamma irradiation and leukoreduction were not used.

MATERIALS AND METHODS

PC production and distribution data were retrospectively analysed in two periods. Period 1 (P1) included 3 years of PRP PCs and a transition year (2015-18). Period 2 (P2) included 5 years of PR PCs (2019-23). PC doses were standardized to an equivalent adult dose for both periods. Descriptive statistics were calculated.

RESULTS

HRC produced 10% more PC doses per year on average in P2 compared to P1. Mean annual waste at HRC declined from 23.9% in P1 to 1.1% in P2. Two urban regions consumed 96% of PC doses in P1 and 88.3% in P2. PC distributions increased in 14/18 regions.

CONCLUSION

Standardized dosage, PR and 7-day shelf-life increased PC availability, reduced waste, eliminated bacterial screening and avoided additional costs for arboviral testing, leukoreduction and irradiation. Access to PC transfusion remains limited in Honduras; however, the conversion to pooled PR PCs illustrates the potential to sustainably expand PC distribution in an LMIC.

Implementing pathogen reduction technology while discontinuing blood donor deferral criteria for sexual risk behaviors: A simulation study

BACKGROUND

Combining pathogen reduction technology (PRT) with blood screening may alleviate concerns over the risk of transfusion-transmitted infections (TTI) and support changes in blood donor selection to potentially increase blood availability. This study aimed to estimate the residual risk of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) transfusion-transmission in Canada after implementing PRT, while eliminating deferrals for sexual risk behaviors.

STUDY DESIGN AND METHODS

A probabilistic approach that combined Bayesian networks with Monte Carlo simulations was used to estimate the risk of transfusing HIV-, HBV-, or HCV-contaminated blood components. Different scenarios were considered to compare the current residual risk after PRT implementation, with and without donor deferral criteria for sexual risk behaviors. Donor profiles and blood component outcomes were simulated based on a literature review including the prevalence and incidence of HIV, HBV, and HCV in the Canadian blood donor population; the use of current blood screening assays; and HIV, HBV, and HCV blood donor viral loads.

RESULTS

In the universal PRT scenario (i.e., with PRT/without deferral criteria), the estimated risks of HIV, HBV, and HCV transmission were significantly lower than those in the currently observed scenario (i.e., without PRT/with deferral criteria).

CONCLUSIONS

This risk model suggests that PRT for platelets and plasma (and eventually for RBCs when available) significantly reduces the residual risks of HIV, HBV and HCV transfusion-transmission and could enable the removal of blood donor deferral criteria for sexual risk behaviors.

Platelet Pathogen Reduction Technology-Should We Stay or Should We Go…?

The recent COVID-19 pandemic has significantly challenged blood transfusion services (BTS) for providing blood products and for keeping blood supplies available. The possibility that a similar pandemic event may occur again has induced researchers and transfusionists to investigate the adoption of new tools to prevent and reduce these risks. Similarly, increased donor travelling and globalization, with consequent donor deferral and donor pool reduction, have contributed to raising awareness on this topic. Although recent studies have validated the use of pathogen reduction technology (PRT) for the control of transfusion-transmitted infections (TTI) this method is not a standard of care despite increasing adoption. We present a critical commentary on the role of PRT for platelets and on associated problems for blood transfusion services (BTS). The balance of the cost effectiveness of adopting PRT is also discussed.

Prevalence of Acute Hepatitis E Virus Infections in Swiss Blood Donors 2018-2020

INTRODUCTION

Hepatitis E virus (HEV) genotype 3 is the major cause of acute viral hepatitis in several European countries. It is acquired mainly by ingesting contaminated pork, but has also been reported to be transmitted through blood transfusion. Although most HEV infections, including those via blood products, are usually self-limiting, they may become chronic in immunocompromised persons. It is thus essential to identify HEV-infected blood donations to prevent transmission to vulnerable recipients.

AIMS

Prior to the decision whether to introduce HEV RNA screening for all Swiss blood donations, a 2-year nationwide prevalence study was conducted.

METHODS

All blood donations were screened in pools of 12-24 samples at five regional blood donation services, and HEV RNA-positive pools were subsequently resolved to the individual donation index donation (X). The viral load, HEV IgG and IgM serology, and HEV genotype were determined. Follow-up investigations were conducted on future control donations (X + 1) and previous archived donations of the donor (X - 1) where available.

RESULTS

Between October 2018 and September 2020, 541,349 blood donations were screened and 125 confirmed positive donations were identified (prevalence 1:4331 donations). At the time of blood donation, the HEV RNA-positive individuals were symptom-free. The median viral load was 554 IU/mL (range: 2.01-2,500,000 IU/mL). Men (88; 70%) were more frequently infected than women (37; 30%), as compared with the sex distribution in the Swiss donor population (57% male/43% female, p < 0.01). Of the 106 genotyped cases (85%), all belonged to genotype 3. Two HEV sub-genotypes predominated; 3h3 (formerly 3s) and 3c. The remaining sub-genotypes are all known to circulate in Europe. Five 3ra genotypes were identified, this being a variant associated with rabbits. In total, 85 (68%) X donations were negative for HEV IgM and IgG. The remaining 40 (32%) were positive for HEV IgG and/or IgM, and consistent with an active infection. We found no markers of previous HEV in 87 of the 89 available and analyzed archive samples (X - 1). Two donors were HEV IgG-positive in the X - 1 donation suggesting insufficient immunity to prevent HEV reinfection. Time of collection of the 90 (72%) analyzed X + 1 donations varied between 2.9 and 101.9 weeks (median of 35 weeks) after X donation. As expected, none of those tested were positive for HEV RNA. Most donors (89; 99%) were positive for anti-HEV lgG/lgM (i.e., seroconversion). HEV lgM-positivity (23; 26%) indicates an often-long persistence of lgM antibodies post-HEV infection.

CONCLUSION

The data collected during the first year of the study provided the basis for the decision to establish mandatory HEV RNA universal screening of all Swiss blood donations in minipools, a vital step in providing safer blood for all recipients, especially those who are immunosuppressed.

Spectroscopic view on the interaction between the psoralen derivative amotosalen and DNA

Psoralens are eponymous for PUVA (psoralen plus UV-A radiation) therapy, which inter alia can be used to treat various skin diseases. Based on the same underlying mechanism of action, the synthetic psoralen amotosalen (AMO) is utilized in the pathogen reduction technology of the INTERCEPT® Blood System to inactivate pathogens in plasma and platelet components. The photophysical behavior of AMO in the absence of DNA is remarkably similar to that of the recently studied psoralen 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT). By means of steady-state and time-resolved spectroscopy, intercalation and photochemistry of AMO and synthetic DNA were studied. AMO intercalates with a higher affinity into A,T-only DNA (KD = 8.9 × 10-5 M) than into G,C-only DNA (KD = 6.9 × 10-4 M). AMO covalently photobinds to A,T-only DNA with a reaction quantum yield of ΦR = 0.11. Like AMT, it does not photoreact following intercalation into G,C-only DNA. Femto- and nanosecond transient absorption spectroscopy reveals the characteristic pattern of photobinding to A,T-only DNA. For AMO and G,C-only DNA, signatures of a photoinduced electron transfer are recorded.

End of selection criteria based on sexual orientation: An international symposium on alternatives to donation deferral

BACKGROUND AND OBJECTIVES

Until recently, gay, bisexual and other men who have sex with men (MSM) were deferred from donating blood for 3-12 months since the last male-to-male sexual contact. This MSM deferral has been discontinued by several high-income countries (HIC) that now perform gender-neutral donor selection.

MATERIALS AND METHODS

An international symposium (held on 20-04-2023) gathered experts from seven HICs to (1) discuss how this paradigm shift might affect the mitigation strategies for transfusion-transmitted infections and (2) address the challenges related to gender-neutral donor selection.

RESULTS

Most countries employed a similar approach for implementing a gender-neutral donor selection policy: key stakeholders were consulted; the transition was bridged by time-limited deferrals; donor compliance was monitored; and questions or remarks on anal sex and the number and/or type of sexual partners were often added. Many countries have now adopted a gender-neutral approach in which questions on pre- and post-exposure prophylaxis for human immunodeficiency virus (HIV) have been added (or retained, when already in place). Other countries used mitigation strategies, such as plasma quarantine or pathogen reduction technologies for plasma and/or platelets.

CONCLUSION

The experience with gender-neutral donor selection has been largely positive among the countries covered herein and seems to be acceptable to stakeholders, donors and staff. The post-implementation surveillance data collected so far appear reassuring with regards to safety, although longer observation periods are necessary. The putative risks associated with HIV antiretrovirals should be further investigated.

Bioprospecting of unexplored halophilic actinobacteria against human infectious pathogens

Human pathogenic diseases received much attention recently due to their uncontrolled spread of antimicrobial resistance (AMR) which causes several threads every year. Effective alternate antimicrobials are urgently required to combat those disease causing infectious microbes. Halophilic actinobacteria revealed huge potentials and unexplored cultivable/non-cultivable actinobacterial species producing enormous antimicrobials have been proved in several genomics approaches. Potential gene clusters, PKS and NRPKS from Nocardia, Salinospora, Rhodococcus, and Streptomyces have wide range coding genes of secondary metabolites. Biosynthetic pathways identification via various approaches like genome mining, In silico, OSMAC (one strain many compound) analysis provides better identification of knowing the active metabolites using several databases like AMP, APD and CRAMPR, etc. Genome constellations of actinobacteria particularly the prediction of BGCs (Biosynthetic Gene Clusters) to mine the bioactive molecules such as pigments, biosurfactants and few enzymes have been reported for antimicrobial activity. Saltpan, saltlake, lagoon and haloalkali environment exploring potential actinobacterial strains Micromonospora, Kocuria, Pseudonocardia, and Nocardiopsis revealed several acids and ester derivatives with antimicrobial potential. Marine sediments and marine macro organisms have been found as significant population holders of potential actinobacterial strains. Deadly infectious diseases (IDs) including tuberculosis, ventilator-associated pneumonia and Candidiasis, have been targeted by halo-actinobacterial metabolites with promising results. Methicillin resistant Staphylococus aureus and virus like Encephalitic alphaviruses were potentially targeted by halophilic actinobacterial metabolites by the compound Homoseongomycin from sponge associated antinobacterium. In this review, we discuss the potential antimicrobial properties of various biomolecules extracted from the unexplored halophilic actinobacterial strains specifically against human infectious pathogens along with prospective genomic constellations.

RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity

Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.

Eye drops of human origin-Current status and future needs: Report on the workshop organized by the ISBT Working Party for Cellular Therapies

BACKGROUND AND OBJECTIVES

Serum eye drops (SEDs) are used to treat ocular surface disease (OSD) and to promote ocular surface renewal. However, their use and production are not standardized, and several new forms of human eye drops have been developed.

MATERIALS AND METHODS

The International Society for Blood Transfusion Working Party (ISBT WP) for Cellular Therapies held a workshop to review the current types of eye drops of human origin (EDHO) status and provide guidance.

RESULTS

The ISBT WP for Cellular Therapies introduced the new terminology 'EDHO' to emphasize that these products are analogous to 'medical products of human origin'. This concept encompasses their source (serum, platelet lysate, and cord blood) and the increasingly diverse spectrum of clinical usage in ophthalmology and the need for traceability. The workshop identified the wide variability in EDHO manufacturing, lack of harmonized quality and production standards, distribution issues, reimbursement schemes and regulations. EDHO use and efficacy is established for the treatment of OSD, especially for those refractory to conventional treatments.

CONCLUSION

Production and distribution of single-donor donations are cumbersome and complex. The workshop participants agreed that allogeneic EDHO have advantages over autologous EDHO although more data on clinical efficacy and safety are needed. Allogeneic EDHOs enable more efficient production and, when pooled, can provide enhanced standardization for clinical consistency, provided optimal margin of virus safety is ensured. Newer products, including platelet-lysate- and cord-blood-derived EDHO, show promise and benefits over SED, but their safety and efficacy are yet to be fully established. This workshop highlighted the need for harmonization of EDHO standards and guidelines.

Pathogen inactivation methods to prevent transfusion-transmissible arboviruses: A systematic review and meta-analysis

OBJECTIVE

Arboviruses are emerging as a relevant threat to transfusion safety. Pathogen inactivation methods (PIMs) may reduce the risk of transmission through transfusion, as long as they meet minimum standards for effectiveness. This study aims to assess the log reduction of viral load achieved with different PIMs, according to the blood product they are used on and the arbovirus targeted.

METHODS

Systematic literature review and meta-analysis. Searches were conducted in MEDLINE and Embase. The study protocol was registered in PROSPERO CRD42022312061. We selected records reporting the log reduction of viral load achieved with the main PIMs (amotosalen + UVA light [INTERCEPT], riboflavin + UV light [Mirasol], methylene blue + visible light/UVC light [THERAFLEX], solvent detergent, amustaline [INTERCEPT] and PEN110 [Inactine]), applied to any blood product (plasma, platelets, red blood cells or whole blood) and for any arbovirus. The log reduction of viral loads was assessed by obtaining the mean log reduction factor (LRF). We compared and classified the LRF of different techniques using statistical methods.

RESULTS

We included 59 publications reporting LRF results in 17 arboviruses. For 13 arboviruses, including Chikungunya virus, Dengue virus, West Nile virus and Zika virus, at least one of the methods achieves adequate or optimal log reduction of viral load-mean LRF ≥4. The LRF achieved with riboflavin + UV light is inferior to the rest of the techniques, both overall and specifically for plasma, platelets preserved in platelet additive solution (PAS)/plasma, and red blood cells/whole blood. The LRF achieved using Mirasol is also lower for inactivating Chikungunya virus, Dengue virus and Zika virus. For West Nile virus, we found no significant differences. In plasma, the method that achieves the highest LRF is solvent/detergent; in platelets, THERAFLEX and INTERCEPT; and in red blood cells/whole blood, PEN110 (Inactine).

CONCLUSION

Not all PIMs achieve the same LRF, nor is this equivalent between the different arboviruses or blood products. Overall, the LRFs achieved using riboflavin + UV light (Mirasol) are inferior to those achieved with the rest of the PIMs. Regarding the others, LRFs vary by arbovirus and blood product. In light of the threat of different arboviruses, blood establishments should have already validated PIMs and be logistically prepared to implement these techniques quickly.

Longitudinal analysis of annual national hemovigilance data to assess pathogen reduced platelet transfusion trends during conversion to routine universal clinical use and 7-day storage

BACKGROUND

France converted to universal pathogen reduced (PR; amotosalen/UVA) platelets in 2017 and extended platelet component (PC) shelf-life from 5- to 7-days in 2018 and 2019. Annual national hemovigilance (HV) reports characterized longitudinal PC utilization and safety over 11 years, including several years prior to PR adoption as the national standard of care.

METHODS

Data were extracted from published annual HV reports. Apheresis and pooled buffy coat [BC] PC use was compared. Transfusion reactions (TRs) were stratified by type, severity, and causality. Trends were assessed for three periods: Baseline (2010-14; ~7% PR), Period 1 ([P1] 2015-17; 8%-21% PR), and Period 2 ([P2] 2018-20; 100% PR).

RESULTS

PC use increased by 19.1% between 2010 and 2020. Pooled BC PC production increased from 38.8% to 68.2% of total PCs. Annual changes in PCs issued averaged 2.4% per year at baseline, -0.02% (P1) and 2.8% (P2). The increase in P2 coincided with a reduction in the target platelet dose and extension to 7-day storage. Allergic reactions, alloimmunization, febrile non-hemolytic TRs, immunologic incompatibility, and ineffective transfusions accounted for >90% of TRs. Overall, TR incidence per 100,000 PCs issued declined from 527.9 (2010) to 345.7 (2020). Severe TR rates declined 34.8% between P1-P2. Forty-six transfusion-transmitted bacterial infections (TTBI) were associated with conventional PCs during baseline and P1. No TTBI were associated with amotosalen/UVA PCs. Infections with Hepatitis E (HEV) a non-enveloped virus resistant to PR, were reported in all periods.

DISCUSSION

Longitudinal HV analysis demonstrated stable PC utilization trends with reduced patient risk during conversion to universal 7-day amotosalen/UVA PCs.

Platelet transfusion in adults: An update

Many patients worldwide receive platelet components (PCs) through the transfusion of diverse types of blood components. PC transfusions are essential for the treatment of central thrombocytopenia of diverse causes, and such treatment is beneficial in patients at risk of severe bleeding. PC transfusions account for almost 10% of all the blood components supplied by blood services, but they are associated with about 3.25 times as many severe reactions (attributable to transfusion) than red blood cell transfusions after stringent in-process leukoreduction to less than 10⁶ residual cells per blood component. PCs are not homogeneous, due to the considerable differences between donors. Furthermore, the modes of PC collection and preparation, the safety precautions taken to limit either the most common (allergic-type reactions and febrile non-hemolytic reactions) or the most severe (bacterial contamination, pulmonary lesions) adverse reactions, and storage and conservation methods can all result in so-called PC "storage lesions". Some storage lesions affect PC quality, with implications for patient outcome. Good transfusion practices should result in higher levels of platelet recovery and efficacy, and lower complication rates. These practices include a matching of tissue ABH antigens whenever possible, and of platelet HLA (and, to a lesser extent, HPA) antigens in immunization situations. This review provides an overview of all the available information relating to platelet transfusion, from donor and donation to bedside transfusion, and considers the impact of the measures applied to increase transfusion efficacy while improving safety and preventing transfusion inefficacy and refractoriness. It also considers alternatives to platelet component (PC) transfusion.

Orthopox viruses and the safety margins of solvent-detergent treated plasma-derived medicinal products

BACKGROUND

The currently ongoing outbreak of monkeypox virus in many non-endemic countries around the world has also raised concerns about the safety of plasma-derived medicinal products. Based on what is known about the poxviridae, that is, that members are exceedingly large and carry a lipid envelope, effective removal and inactivation by plasma product manufacturing processes is expected. For the widely used solvent-detergent (S/D) treatments, however, poxviruses have been reported as potentially being a bit more resistant.

STUDY DESIGN AND METHODS

Using a S/D mixture comprising tri-n-butyl-phosphate, polysorbate 80 and Triton X-100 (TX-100), inactivation of vaccinia virus (a model closely resembling monkeypox virus, both within the same genus, i.e., Orthopoxvirus) in a plasma-derived process intermediate was analyzed over 60 min. As use of Triton X-100 will, based on environmental concerns, be restricted, similar experiments were conducted with a physicochemically virtually identical alternative, Nereid.

RESULTS

Fast inactivation of vaccinia virus to the assay detection limit, that is, reduction of infectivity by greater than 4 log₁₀ within 10-20 min, was measured for the TX-100 S/D mixture. The alternative S/D mixture (Nereid instead of TX-100) was found fully equivalent.

CONCLUSION

As for other lipid-enveloped viruses, treatment of process intermediates with S/D mixtures containing TX-100 or the closely related detergent Nereid are highly effective in inactivating poxviruses. Thus, the current spread of monkeypox virus does not compromise the viral safety margins of plasma-derived medicines.

Insights on 21 Years of HBV Surveillance in Blood Donors in France

Hepatitis B virus (HBV) infection is the most frequent viral infection found in blood donors (BDs) in France. We analyzed the epidemiological and sero-molecular data on HBV infection gathered over the past two decades by the French haemovigilance surveillance network, blood screening laboratories, and the national reference center for transfusion infectious risks (NRC). Between 2000 and 2020, 6149 of the 58,160,984 donations (1.06/10,000) tested HBV positive, 98% of them from first-time blood donors (FTBDs). In addition, 2212 (0.0071%) of the 30,977,753 donations screened for HBV DNA tested DNA positive, of which 25 (1.1%) were positive only for this marker. HBV prevalence decreased by 2.8-fold and the residual risk for transfusion-transmitted HBV infection decreased 13-fold and was divided by 13. The major risk factor for HBV infection was the origin of donors (endemic country, 66.5%), followed by parenteral exposure (10.7%). In the whole HBV-positive BD population, genotype D was predominant (41.8%), followed by genotypes A (26.2%) and E (20.4%), reflecting the geographical origin of donors. The low and decreasing prevalence and incidence of HBV infection in French BDs, coupled with a screening strategy using three HBV markers (HBsAg, anti-HBc and DNA), ensures a high level of blood safety, further reinforced by the implementation of pathogen-reduction measures.

Inflammatory profile of convalescent plasma to treat COVID: Impact of amotosalen/UVA pathogen reduction technology

Blood products in therapeutic transfusion are now commonly acknowledged to contain biologically active constituents during the processes of preparation. In the midst of a worldwide COVID-19 pandemic, preliminary evidence suggests that convalescent plasma may lessen the severity of COVID-19 if administered early in the disease, particularly in patients with profound B-cell lymphopenia and prolonged COVID-19 symptoms. This study examined the influence of photochemical Pathogen Reduction Treatment (PRT) using amotosalen‐HCl and UVA light in comparison with untreated control convalescent plasma (n= 72 – paired samples) - cFFP, regarding soluble inflammatory factors: sCD40L, IFN-alpha, IFN-beta, IFN-gamma, IL-1 beta, IL-6, IL-8, IL-10, IL-18, TNF-alpha and ex-vivo inflammatory bioactivity on endothelial cells. We didn’t observe significant modulation of the majority of inflammatory soluble factors (8 of 10 molecules tested) pre- or post-PRT. We noted that IL-8 concentrations were significantly decreased in cFFP with PRT, whereas the IL-18 concentration was increased by PRT. In contrast, endothelial cell release of IL-6 was similar whether cFFP was pre-treated with or without PRT. Expression of CD54 and CD31 in the presence of cFFP were similar to control levels, and both were significant decreased in when cFFP had been pre-treated by PRT. It will be interesting to continue investigations of IL-18 and IL-8, and the physiopathological effect of PRT- treated convalescent plasma and in clinical trials. But overall, it appears that cFFP post-PRT were not excessively pro-inflammatory. Further research, including a careful clinical evaluation of CCP-treated patients, will be required to thoroughly define the clinical relevance of these findings.

Detection frequencies and viral load distribution of parvovirus B19 DNA in blood and plasma donations in England

BACKGROUND AND OBJECTIVES

Infections with human parvovirus B19 (B19V) are transmissible by blood components and plasma-derived medicines. The European Pharmacopoeia regulates maximum levels of virus allowed in manufacturers' plasma pools. To evaluate contamination risk prior to re-introduction of UK-sourced plasma for manufacturing, we investigated viraemia frequencies of B19V in plasma samples collected from blood donors before and during COVID-enforced lockdown.

MATERIALS AND METHODS

Quantitative PCR for B19V DNA was used to screen pools of 96 anonymised plasma samples collected in England from 2017 (n = 29 505), 2020 (n = 3360) and 2021 (n = 43 200). Selected positive pools were resolved into individual samples. Data on donor notifications and related lookback investigations were collected from European countries by on-line survey in 2020.

RESULTS

Screening of 76 065 donations identified 80 B19V-positive pools. While most positive samples had low viral loads (<10⁵  IU ml^-1 ), primarily from 2017 (77/29 505; 0.3%), two contained high levels of B19V DNA (1.3 × 10⁸ and 6.3 × 10⁶ IU ml^-1 ), both likely to contaminate a final manufacturer's pool and lead to discard. The incidence of B19V infection during lockdown was reduced (1/3360 in 2020; 0/43 200 in 2021). Genomic analysis of positive pools resolved to single samples identified B19V genotype 1 in all nine samples. Seroprevalence of anti-B19V IgG antibodies was 75% (143/192). A survey of B19V screening practices in Europe demonstrated considerable variability. Two blood establishments informed infected blood donors of positive B19V results.

CONCLUSION

Information on seroprevalence, incidence and viral loads of B19V viraemia is contributory the evaluation of alternative operational screening strategies for plasma testing.

Ultrafast-UV laser integrating cavity device for inactivation of SARS-CoV-2 and other viruses

Ultraviolet (UV) irradiation-based methods used for viral inactivation have provided an important avenue targeting severe acute respiratory-syndrome coronavirus-2 (SARS-CoV-2) virus. A major problem with state-of-the-art UV inactivation technology is that it is based on UV lamps, which have limited efficiency, require high power, large doses, and long irradiation times. These drawbacks limit the use of UV lamps in air filtering systems and other applications. To address these limitations, herein we report on the fabrication of a device comprising a pulsed nanosecond 266 nm UV laser coupled to an integrating cavity (LIC) composed of a UV reflective material, polytetrafluoroethylene. Previous UV lamp inactivation cavities were based on polished walls with specular reflections, but the diffuse reflective UV ICs were not thoroughly explored for virus inactivation. Our results show that LIC device can inactivate several respiratory viruses including SARS-CoV-2, at ~ 1 ms effective irradiation time, with > 2 orders of magnitude higher efficiency compared to UV lamps. The demonstrated 3 orders of magnitude cavity enhancement relative to direct exposure is crucial for the development of efficient real-time UV air and water purification systems. To the best of our knowledge this is the first demonstration of LIC application for broad viral inactivation with high efficiency.

Mitigating the risk of transfusion-transmitted infections with vector-borne agents solely by means of pathogen reduction

Background

This study evaluated whether pathogen reduction technology (PRT) in plasma and platelets using amotosalen/ultraviolet A light (A/UVA) or in red blood cells using amustaline/glutathione (S‐303/GSH) may be used as the sole mitigation strategy preventing transfusion‐transmitted West Nile (WNV), dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viral, and Babesia microti, Trypanosoma cruzi, and Plasmodium parasitic infections.

Methods

Antibody (Ab) status and pathogen loads (copies/mL) were obtained for donations from US blood donors testing nucleic acid (NAT)‐positive for WNV, DENV, ZIKV, CHIKV, and B. microti. Infectivity titers derived from pathogen loads were compared to published PRT log₁₀ reduction factors (LRF); LRFs were also reviewed for Plasmodium and T. cruzi. The potential positive impact on donor retention following removal of deferrals from required questioning and testing for WNV, Babesia, Plasmodium, and T. cruzi was estimated for American Red Cross (ARC) donors.

Results

A/UVA and S‐303/GSH reduced infectivity to levels in accordance with those recognized by FDA as suitable to replace testing for all agents evaluated. If PRT replaced deferrals resulting from health history questions and/or NAT for WNV, Babesia, Plasmodium, and T. cruzi, 27,758 ARC donors could be retained allowing approximately 50,000 additional donations/year based on 1.79 donations/donor for calendar year 2019 (extrapolated to an estimated 125,000 additional donations nationally).

Conclusion

Pathogen loads in donations from US blood donors demonstrated that robust PRT may provide an opportunity to replace deferrals associated with donor questioning and NAT for vector‐borne agents allowing for significant donor retention and likely increased blood availability.

Inactivation of SARS-CoV-2 in All Blood Components Using Amotosalen/Ultraviolet A Light and Amustaline/Glutathione Pathogen Reduction Technologies

No cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transfusion-transmitted infections (TTI) have been reported. The detection of viral RNA in peripheral blood from infected patients and blood components from infected asymptomatic blood donors is, however, concerning. This study investigated the efficacy of the amotosalen/UVA light (A/UVA) and amustaline (S-303)/glutathione (GSH) pathogen reduction technologies (PRT) to inactivate SARS-CoV-2 in plasma and platelet concentrates (PC), or red blood cells (RBC), respectively. Plasma, PC prepared in platelet additive solution (PC-PAS) or 100% plasma (PC-100), and RBC prepared in AS-1 additive solution were spiked with SARS-CoV-2 and PR treated. Infectious viral titers were determined by plaque assay and log reduction factors (LRF) were determined by comparing titers before and after treatment. PR treatment of SARS-CoV-2-contaminated blood components resulted in inactivation of the infectious virus to the limit of detection with A/UVA LRF of >3.3 for plasma, >3.2 for PC-PAS-plasma, and >3.5 for PC-plasma and S-303/GSH LRF > 4.2 for RBC. These data confirm the susceptibility of coronaviruses, including SARS-CoV-2 to A/UVA treatment. This study demonstrates the effectiveness of the S-303/GSH treatment to inactivate SARS-CoV-2, and that PRT can reduce the risk of SARS-CoV-2 TTI in all blood components.

Robust inactivation of Plasmodium falciparum in red blood cell concentrates using amustaline and glutathione pathogen reduction

BACKGROUND

Plasmodium falciparum is the parasite responsible for most malaria cases globally. The risk of transfusion-transmitted malaria (TTM) is mitigated by donor deferrals and blood screening strategies, which adversely impact blood availability. Previous studies showed robust inactivation of P. falciparum using nucleic acid-targeting pathogen reduction technologies (PRT) for the treatment of plasma and platelet components or whole blood (WB). The efficacy of the amustaline-glutathione (GSH) PRT to inactivate P. falciparum is here evaluated in red blood cells (RBC), as well the impact of PRT on parasite loads, stages, and strains.

STUDY DESIGN AND METHODS

RBC units resuspended in AS-1 or AS-5 additive solutions were spiked with ring stage-infected RBC and treated with the amustaline-GSH PRT. Parasite loads and viability were measured in samples at the time of contamination, and after treatment, using serial 10-fold dilutions of the samples in RBC cultures maintained for up to 4 weeks.

RESULTS

P. falciparum viability assays allow for the detection of very low levels of parasite. Initial parasite titer was >5.2 log₁₀ /ml in AS-1/5 RBC. No infectious parasites were detected in amustaline-GSH-treated samples after 4 weeks of culture. Amustaline-GSH inactivated high parasite loads regardless of parasite stages and strains. Amustaline readily penetrates the parasite, irreversibly blocks development, and leads to parasite death and expulsion from RBC.

DISCUSSION

Amustaline-GSH PRT demonstrated robust efficacy to inactivate malaria parasites in RBC concentrates. This study completes the portfolio of studies demonstrating the efficacy of nucleic acid-targeting PRTs to mitigate TTM risks as previously reported for platelet concentrates, plasma, and WB.

Antibody profiles in COVID ‐19 convalescent plasma prepared with Amotosalen/ UVA pathogen reduction treatment

Background

COVID‐19 convalescent plasma (CCP), from donors recovered from severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection, is one of the limited therapeutic options currently available for the treatment of critically ill patients with COVID‐19. There is growing evidence that CCP may reduce viral loads and disease severity; and reduce mortality. However, concerns about the risk of transfusion‐transmitted infections (TTI) and other complications associated with transfusion of plasma, remain. Amotosalen/UVA pathogen reduction treatment (A/UVA‐PRT) of plasma offers a mitigation of TTI risk, and when combined with pooling has the potential to increase the diversity of the polyclonal SARS‐CoV‐2 neutralizing antibodies.

Study design and methods

This study assessed the impact of A/UVA‐PRT on SARS‐CoV‐2 antibodies in 42 CCP using multiple complimentary assays including antigen binding, neutralizing, and epitope microarrays. Other mediators of CCP efficacy were also assessed.

Results

A/UVA‐PRT did not negatively impact antibodies to SARS‐CoV‐2 and other viral epitopes, had no impact on neutralizing activity or other potential mediators of CCP efficacy. Finally, immune cross‐reactivity with other coronavirus antigens was observed raising the potential for neutralizing activity against other emergent coronaviruses.

Conclusion

The findings of this study support the selection of effective CCP combined with the use of A/UVA‐PRT in the production of CCP for patients with COVID‐19.

Hemostatic efficacy of pathogen-reduced platelets in children undergoing cardiopulmonary bypass

BACKGROUND

Pediatric patients undergoing cardiopulmonary bypass (CPB) often require blood component transfusions. Pathogen-reduction (PR) of platelets reduces the risk of microbial contamination; however, its effect on hemostatic efficacy in this population is unclear. This study sought to characterize the hemostatic efficacy of PR platelets in children undergoing CPB.

STUDY DESIGN AND METHODS

We performed a retrospective chart review of patients admitted to a pediatric intensive care unit following CPB surgery from 2015 to 2019. Demographic data, validated scoring of repair complexity, products received, and outcomes were compared. The primary outcome was postoperative chest tube bleeding.

RESULTS

A total of 140 patients were enrolled. The majority of surgeries (124/140) were Risk Adjustment for Congenital Heart Surgery (RACHS) 1-3 repairs. Seventy-four percent of patients (104/140) received only standard platelets whereas 26% (36/140) received PR platelets. There were no differences between the groups in the age (p = .90), sex (p = .20) or RACHS score (p = .06). Postoperatively, there was no difference in the median chest tube output for 1 h (p = .27), 2 h (p = .26), 4 h (p = .09), 8 h (p = .16), or for the first 24 h following surgery (p = .23) in patients who received standard versus PR platelets. There was also no difference in receipt of platelets (p = .18), cell saver (p = .79), or cryoprecipitate (p = .28).

CONCLUSION

Patients receiving PR platelets did not have more blood loss or require more transfusions than those who received standard platelets. This suggests that PR platelets may provide acceptable hemostasis with the additional benefits of reduced risk of microbial contamination in pediatric patients undergoing CPB.

Expanded validation of the effect and quality of a pathogen inactivation system based on riboflavin photochemistry on platelet bacterial contamination

Background

Bacterial contamination still poses serious challenges to blood safety. Platelets have the highest bacterial contamination risk of all blood components.

Methods

Twenty units of manual platelets were prepared from blood donated by our hospital, which were inoculated with Staphylococcus aureus and Escherichia coli suspensions. The riboflavin sodium phosphate solution was added into platelets, adjusted to a final concentration of 160 μmol/L. Platelets added into an illumination bag and placed in the inactivation system for riboflavin photochemistry at various doses. The inactivation effect of bacteria was evaluated on a Columbia blood agar plate by the plate counting method. Meanwhile, the blood routine, blood gas analysis, platelet aggregation test, and thromboelastogram of platelets before and after treatment were detected to evaluate the changes of platelet quality after treatment.

Results

the inactivation effect of S. aureus and E. coli at the inactivation dose (16.9 J/cm²) could reach more than 4 logs. After treatment at 16.9 J/cm², the blood routine results showed that the platelet count was significantly different (P<0.05), and the blood gas analysis showed that the oxygen partial pressure (pO₂) and lactic acid concentration (cLac) were also significantly different (P<0.05). After 16.9 J/cm² treatment, there was a significant difference between Arachidonic acid (AA) and Collagen (Cog) activator groups in the platelet aggregation experiment (P<0.05), but there was no significant difference in the main thrombelastogram (TEG) parameters (R value, K value, angle value, MA value) after treatment (P>0.05).

Conclusions

The inactivation effect of this set of blood component pathogen inactivation system on platelet bacterial contamination could be considered to meet actual clinical needs, with the inactivation treatment having little impact on platelet function.

Impact of different pathogen reduction technologies on the biochemistry, function, and clinical effectiveness of platelet concentrates: An updated view during a pandemic

Standard platelet concentrates (PCs) stored at 22°C have a limited shelf life of 5 days. Because of the storage temperature, bacterial contamination of PCs can result in life‐threatening infections in transfused patients. The potential of blood components to cause infections through contaminating pathogens or transmitting blood‐borne diseases has always been a concern. The current safety practice to prevent pathogen transmission through blood transfusion starts with a stringent screening of donors and regulated testing of blood samples to ensure that known infections cannot reach transfusion products. Pathogen reduction technologies (PRTs), initially implemented to ensure the safety of plasma products, have been adapted to treat platelet products. In addition to reducing bacterial contamination, PRT applied to PCs can extend their shelf life up to 7 days, alleviating the impact of their shortage, while providing an additional safety layer against emerging blood‐borne infectious diseases. While a deleterious action of PRTs in quantitative and qualitative aspects of plasma is accepted, the impact of PRTs on the quality, function, and clinical efficacy of PCs has been under constant examination. The potential of PRTs to prevent the possibility of new emerging diseases to reach cellular blood components has been considered more hypothetical than real. In 2019, a coronavirus‐related disease (COVID‐19) became a pandemic. This episode should help when reconsidering the possibility of future blood transmissible threats. The following text intends to evaluate the impact of different PRTs on the quality, function, and clinical effectiveness of platelets within the perspective of a developing pandemic.

The 4-Year Experience with Implementation and Routine Use of Pathogen Reduction in a Brazilian Hospital

(1) Background: We reviewed the logistics of the implementation of pathogen reduction (PR) using the INTERCEPT Blood System™ for platelets and the experience with routine use and clinical outcomes in the patient population at the Sírio-Libanês Hospital of São Paulo, Brazil. (2) Methods: Platelet concentrate (PC), including pathogen reduced (PR-PC) production, inventory management, discard rates, blood utilization, and clinical outcomes were analyzed over the 40 months before and after PR implementation. Age distribution and wastage rates were compared over the 10 months before and after approval for PR-PC to be stored for up to seven days. (3) Results: A 100% PR-PC inventory was achieved by increasing double apheresis collections and production of double doses using pools of two single apheresis units. Discard rates decreased from 6% to 3% after PR implementation and further decreased to 1.2% after seven-day storage extension for PR-PCs. The blood utilization remained stable, with no increase in component utilization. A significant decrease in adverse transfusion events was observed after the PR implementation. (4) Conclusion: Our experience demonstrates the feasibility for Brazilian blood centers to achieve a 100% PR-PC inventory. All patients at our hospital received PR-PC and showed no increase in blood component utilization and decreased rates of adverse transfusion reactions.

Efficient inactivation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in human apheresis platelet concentrates with amotosalen and ultraviolet A light

Objectives

The detection of SARS-CoV-2 RNA in blood and platelet concentrates from asymptomatic donors, and the detection of viral particles on the surface and inside platelets during in vitro experiments, raised concerns over the potential risk for transfusion-transmitted-infection (TTI). The objective of this study was to assess the efficacy of the amotosalen/UVA pathogen reduction technology for SARS-CoV-2 in human platelet concentrates to mitigate such potential risk.

Material and methods

Five apheresis platelet units in 100% plasma were spiked with a clinical SARS-CoV-2 isolate followed by treatment with amotosalen/UVA (INTERCEPT Blood System), pre- and posttreatment samples were collected as well as untreated positive and negative controls. The infectious viral titer was assessed by plaque assay and the genomic titer by quantitative RT-PCR. To exclude the presence of infectious particles post-pathogen reduction treatment below the limit of detection, three consecutive rounds of passaging on permissive cell lines were conducted.

Results

SARS-CoV-2 in platelet concentrates was inactivated with amotosalen/UVA below the limit of detection with a mean log reduction of > 3.31 ± 0.23. During three consecutive rounds of passaging, no viral replication was detected. Pathogen reduction treatment also inhibited nucleic acid detection with a log reduction of > 4.46 ± 0.51 PFU equivalents.

Conclusion

SARS-CoV-2 was efficiently inactivated in platelet concentrates by amotosalen/UVA treatment. These results are in line with previous inactivation data for SARS-CoV-2 in plasma as well as MERS-CoV and SARS-CoV-1 in platelets and plasma, demonstrating efficient inactivation of human coronaviruses.

Viral reduction of human blood by ultraviolet A-photosensitized vitamin K5

Blood product transfusion can transmit viral pathogens. Pathogen reduction methods for blood products have been developed but, so far, are not available for whole blood. We evaluated if vitamin K5 (VK5) and ultraviolet A (UVA) irradiation could be used for virus inactivation in plasma and whole blood. Undiluted human plasma and whole blood diluted to 20% were spiked with high levels of vaccinia or Zika viruses. Infectious titers were measured by standard TCID₅₀ assay before and after VK5/UVA treatments. Up to 3.6 log of vaccinia and 3.2 log of Zika were reduced in plasma by the combination of 500 μM VK5 and 3 J/cm² UVA, and 3.1 log of vaccinia and 2.9 log of Zika were reduced in diluted human blood (20%) by the combination of 500 μM VK5 and 70 J/cm² UVA. At end of whole blood treatment, hemolysis increased from 0.18% to 0.41% but remained below 1% hemolysis, which is acceptable to the Food and Drug Administration for red cell transfusion products. No significant alteration of biochemical parameters of red blood cells occurred with treatment. Our results provide proof of the concept that a viral pathogen reduction method based on VK5/UVA may be developed for whole blood.

Validation of Inactivation Methods for Arenaviruses

Several of the human-pathogenic arenaviruses cause hemorrhagic fever and have to be handled under biosafety level 4 conditions, including Lassa virus. Rapid and safe inactivation of specimens containing these viruses is fundamental to enable downstream processing for diagnostics or research under lower biosafety conditions. We established a protocol to test the efficacy of inactivation methods using the low-pathogenic Morogoro arenavirus as surrogate for the related highly pathogenic viruses. As the validation of chemical inactivation methods in cell culture systems is difficult due to cell toxicity of commonly used chemicals, we employed filter devices to remove the chemical and concentrate the virus after inactivation and before inoculation into cell culture. Viral replication in the cells was monitored over 4 weeks by using indirect immunofluorescence and immunofocus assay. The performance of the protocol was verified using published inactivation methods including chemicals and heat. Ten additional methods to inactivate virus in infected cells or cell culture supernatant were validated and shown to reduce virus titers to undetectable levels. In summary, we provide a robust protocol for the validation of chemical and physical inactivation of arenaviruses in cell culture, which can be readily adapted to different inactivation methods and specimen matrices.

Platelet Transfusion-Insights from Current Practice to Future Development

Since the late sixties, therapeutic or prophylactic platelet transfusion has been used to relieve hemorrhagic complications of patients with, e.g., thrombocytopenia, platelet dysfunction, and injuries, and is an essential part of the supportive care in high dose chemotherapy. Current and upcoming advances will significantly affect present standards. We focus on specific issues, including the comparison of buffy-coat (BPC) and apheresis platelet concentrates (APC); plasma additive solutions (PAS); further measures for improvement of platelet storage quality; pathogen inactivation; and cold storage of platelets. The objective of this article is to give insights from current practice to future development on platelet transfusion, focusing on these selected issues, which have a potentially major impact on forthcoming guidelines.

Plasma pooling in combination with amotosalen/UVA pathogen inactivation to increase standardisation and safety of therapeutic plasma units

Objectives

Assessment of the impact of pooling five single‐donor plasma (SDP) units to obtain six pathogen‐reduced therapeutic plasma (PTP) units on standardisation and the retention of labile coagulation factors.

Background

SDP shows a high inter‐donor variability with potential implications for the clinical treatment outcome. Additionally, there is still an existing risk for window‐period transmissions of blood borne pathogens including newly emerging pathogens.

Methods/Materials

Five ABO‐identical SDP units were pooled, treated with the INTERTCEPT™ Blood System (Cerus Corporation, U.S.A.) and split into six PTP units which were frozen and thawed after 30 days. The variability in volume, labile coagulation factor retention and activity was assessed.

Results

The variability of volumes between the PTP units was reduced by 46% compared to SDP units. The variability in coagulation factor content between the PTP units was reduced by 63% compared to SDP units. Moderate, but significant losses of coagulation factors (except for vWF) were observed in PTPs compared to SDPs.

Conclusion

The pooling of five SDP units to obtain six PTP units significantly increases product standardisation with potential implications for safety, economics as well as transfusion‐transmitted pathogen safety, making it an interesting alternative to quarantine SDP (qSDP) and pathogen‐reduced SDP.

Impact of pathogen-reduction technologies on COVID-19 convalescent plasma potency

Pathogen reduction technologies (PRT) have been recommended by many regulatory authorities to minimize the residual risk of transfusion-transmitted infections associated with COVID19 convalescent plasma. While its impact on safety and its cost-effectiveness are nowadays well proven, there is theoretical concern that PRT could impact efficacy of convalescent plasma by altering concentration and/or function of the neutralizing antibodies (nAb). We review here the evidence supporting a lack of significant detrimental effect from PRTs on nAbs.

Amotosalen and ultraviolet A light treatment efficiently inactivates severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human plasma

Background and objectives

During the ongoing pandemic of COVID‐19, SARS‐CoV‐2 RNA was detected in plasma and platelet products from asymptomatic blood donors, raising concerns about potential risk of transfusion transmission, also in the context of the current therapeutic approach utilizing plasma from convalescent donors. The objective of this study was to assess the efficacy of amotosalen/UVA light treatment to inactivate SARS‐CoV‐2 in human plasma to reduce the risk of potential transmission through blood transfusion.

Methods

Pools of three whole‐blood‐derived human plasma units (630–650 ml) were inoculated with a clinical SARS‐CoV‐2 isolate. Spiked units were treated with amotosalen/UVA light (INTERCEPT Blood System™) to inactivate SARS‐CoV‐2. Infectious titres and genomic viral load were assessed by plaque assay and real‐time quantitative PCR. Inactivated samples were subject to three successive passages on permissive tissue culture to exclude the presence of replication‐competent viral particles.

Results

Inactivation of infectious viral particles in spiked plasma units below the limit of detection was achieved by amotosalen/UVA light treatment with a mean log reduction of >3·32 ± 0·2. Passaging of inactivated samples on permissive tissue showed no viral replication even after 9 days of incubation and three passages, confirming complete inactivation. The treatment also inhibited NAT detection by nucleic acid modification with a mean log reduction of 2·92 ± 0·87 PFU genomic equivalents.

Conclusion

Amotosalen/UVA light treatment of SARS‐CoV‐2 spiked human plasma units efficiently and completely inactivated >3·32 ± 0·2 log of SARS‐CoV‐2 infectivity, showing that such treatment could minimize the risk of transfusion‐related SARS‐CoV‐2 transmission.

Screening for SARS-CoV-2 antibodies in convalescent plasma in Brazil: Preliminary lessons from a voluntary convalescent donor program

BACKGROUND

Coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) collection began in two Brazilian hospitals for treatment of severe/critical patients.

METHODS AND MATERIALS

Mild/moderate COVID-19 convalescents were selected as CCP donors after reverse transcription polymerase chain reaction (RT-PCR) confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and absence of symptoms for ≥14 days plus (a) age (18-60 years), body weight greater than 55 kg; (b) immunohematological studies; (c) no infectious markers of hepatitis B virus, hepatitis C virus, human immunodeficiency virus, human T-lymphotropic virus-1/2, Chagas and syphilis infection; (d) no HLA antibodies (multiparous); (e) second RT-PCR (nasopharyngeal swab and/or blood) negativity; (f) virus neutralization test (cytopathic effect-based virus neutralization test neutralizing antibody) and anti-nucleocapsid protein SARS-CoV-2 IgM, IgG, and IgA enzyme-linked immunosorbent assays.

RESULTS

Among 271 donors (41 females, 230 males), 250 presented with neutralizing antibodies. Final RT-PCR was negative on swab (77.0%) or blood (88.4%; P = .46). Final definition of RT-PCR was only defined at more than 28 days after full recovery in 59 of 174 (33.9%) RT-PCR -ve, and 25/69 RT-PCR +ve (36.2%; 13 between 35 and 48 days). Neutralizing antibody titers of 160 or greater were found in 63.6%. Correlation between IgG signal/cutoff of 5.0 or greater and neutralizing antibody of 160 or greater was 82.4%. Combination of final RT-PCR -ve with neutralizing antibody ≥160 was 41.3% (112/271). Serial plasma collection showed decline in neutralizing antibody titers and IgA levels (P < .05), probably denoting a "golden period" for CCP collection (≤28 days after joining the program); IgA might have an important role as neutralizing antibody. Donor's weight, days between disease onset and serial plasma collection, and IgG and IgM levels are important predictors for neutralizing antibody titer.

CONCLUSIONS

RT-PCR +ve cases are still detected in 36.2% within 28 to 48 days after recovery. High anti-nucleocapsid protein IgG levels may be used as a surrogate marker to neutralizing antibody.

Synergistic bactericidal effects of pairs of photosensitizer molecules activated by ultraviolet A light against bacteria in plasma

BACKGROUND

The current approach to reducing bacterial contamination in blood transfusion products is through detection or pathogen reduction methods, some of which utilize ultraviolet (UV) light photosensitizers. A small number of photosensitizers are being used as single agents in combination with UV light, but their efficacy can be limited against some pathogens. Benzophenone (BP) and vitamins B1, B6, and K3 have been identified as effective UVA photosensitizers for inactivation of bacteria. We evaluated whether combining pairs of photosensitizers in this group would have synergistic bactericidal effects on Gram-negative and Gram-positive bacteria.

STUDY DESIGN AND METHODS

Bacteria species of Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Klebsiella pneumoniae were mixed with 0 to 100 mM concentrations of photosensitizers and exposed to UVA irradiation at 18 J/cm² to assess their bactericidal effects.

RESULTS

Single photosensitizers irradiated with UVA produced a range of bactericidal activity. When combined in pairs, all demonstrated some synergistic bactericidal effects with up to 4-log reduction above the sum of activities of individual molecules in the pair against bacteria in plasma. Photosensitizer pairs with BP had the highest synergism across all bacteria. With vitamin K3 in the pair, synergism was evident for Gram-positive but not for Gram-negative bacteria. Vitamin B1 and vitamin B6 had the least synergism. These results indicate that a combination approach with multiple photosensitizers may extend effectiveness of pathogen reduction in plasma.

CONCLUSIONS

Combining photosensitizers in pathogen reduction methods could improve bactericidal efficacy and lead to use of lower concentrations of photosensitizers to reduce toxicities and unwanted side effects.

Sepsis from an apheresis platelet contaminated with Acinetobacter calcoaceticus/baumannii complex bacteria and Staphylococcus saprophyticus after pathogen reduction

BACKGROUND

Strategies to reduce platelet (PLT) bacterial contamination include donor screening, skin disinfection, sample diversion, bacterial culture, pathogen reduction (PR), and day-of-transfusion tests. We report bacterial sepsis following a pathogen-reduced PLT transfusion.

CASE REPORT

An adult male with relapsed acute lymphoblastic leukemia was successfully treated for central catheter-associated Staphylococcus aureus bacteremia. A peripherally inserted central catheter (PICC) was placed. Chills, rigors, and flushing developed immediately after PICC-infused pathogen-reduced PLTs, progressing to septic shock requiring intensive care management.

METHODS

PICC and peripheral blood (PB), transfused bag saline flushes (TBFs), environmental samples, and the pathogen-reduced untransfused co-component (CC) were cultured. Plasma metagenomic and bacterial isolate whole-genome sequencing; PLT mitochondrial DNA (mtDNA) testing of untransfused CC and TBF; CC testing for amotosalen (S-59)/S-59 photoproducts; isolate PR studies (INTERCEPT); and TBF polymerase chain reaction for recipient Y-chromosome DNA were performed.

RESULTS

PB and PICC cultures grew Acinetobacter calcoaceticus/baumannii complex (ACBC). TBF was gram-positive; mass spectrometry identified ACBC and Staphylococcus saprophyticus (SS). CC Gram stain and cultures were negative. Environmental cultures, some done after decontamination, were ACBC/SS negative. Posttransfusion patient plasma and TBF ACBC sequences were genetically identical. No Y-chromosome signal was detected in TBF. S-59 photoproducts and evidence of mtDNA amplification inhibition were found in the CC. Spiking PR studies showed >5.9-log inactivation for both isolates. Donor skin cultures for Acinetobacter were negative.

CONCLUSION

CC sterility, PR studies, residual S-59 photoproducts, and mtDNA amplification inhibition suggest successful PR. Unidentified environmental sources and inherent or acquired bag defects may have contributed to postmanufacturing pathogen-reduced PLT contamination.