Evaluation of Mirasol pathogen reduction system by artificially contaminating platelet concentrates with Staphylococcus epidermidis: A pilot study from India

Molecular validation of pathogen-reduction technologies using rolling-circle amplification coupled with real-time PCR for torquetenovirus DNA quantification

BACKGROUND

Pathogen reduction technologies (PRT) based on nucleic-acid damaging chemicals and/or irradiation are increasingly being used to increase safety of blood components against emerging pathogens, such as convalescent plasma in the ongoing COVID-19 pandemic. Current methods for PRT validation are limited by the resources available to the blood component manufacturer, and quality control rely over pathogen spiking and hence invariably require sacrifice of the tested blood units: quantitative real-time PCR is the current pathogen detection method but, due to the high likelihood of detecting nonviable fragments, requires downstream pathogen culture. We propose here a new molecular validation of PRT based on the highly prevalent human symbiont torquetenovirus (TTV) and rolling circle amplification (RCA).

MATERIALS AND METHODS

Serial apheresis plasma donations were tested for TTV before and after inactivation with Intercept® PRT using real-time quantitative PCR (conventional validation), RCA followed by real-time PCR (our validation), and reverse PCR (for cross-validation).

RESULTS

While only 20% of inactivated units showed significant decrease in TTV viral load using real-time qPCR, all donations tested with RCA followed by real-time PCR showed TTV reductions. As further validation, 2 units were additionally tested with reverse PCR, which confirmed absence of entire circular genomes.

DISCUSSION

We have described and validated a conservative and easy-to-setup protocol for molecular validation of PRT based on RCA and real-time PCR for TTV.

The Role of Glutamine in the Prevention of Ultraviolet-C-Induced Platelet Activation

Background and Objectives. The primary function of platelets is to prevent bleeding. The use of UV-C light in the treatment of platelets has become a valuable method for preserving the efficacy of platelet concentrates in blood banks. However, its deleterious effect remains, such as the activation of platelets, thus causing the platelets to lose their physiological function. In this study, we intended to demonstrate the impact of UV-C on platelets and how the use of glutamine could mitigate the loss of physiological function of the platelets caused by UV-C. Materials and Methods. This study was conducted using mouse platelets. We assessed calcium signaling using Fura-2 AM incubation and dense granule secretion of the platelets using luminescence assay by measuring ATP. At the molecular level, the activation of integrin using PAC-1 antibody was analyzed. Phosphorylation of immune-precipitated cPLA2 was assessed using a specific antibody. All the experiments were carried out with or without glutamine in the presence of UV-C. Positive and negative controls were used in all experiments to validate the findings. Results. We have demonstrated that physiological and biochemical damage arises as a result of the exposure of platelet concentrate to UV-C and that the use of glutamine could alleviate this damage. Various experiments, thrombus formation, integrin activation, and phosphorylation of cPLA2 were preserved using 50 mM of glutamine in the presence of UV-C, which reduces 50% of platelet viability. Conclusions. Our study demonstrates that the storage of platelet concentrates under the UV-C activates their physiological process and renders them to the thrombus formation, hence decreasing their viability. The presence of a moderate amount of glutamine can alleviate the toxic effect of UV-C, and platelet concentrates could be kept viable for a long time.

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.

New strategies for the control of infectious and parasitic diseases in blood donors: the impact of pathogen inactivation methods

Around 70 infectious agents are possible threats for blood safety.

The risk for blood recipients is increasing because of new emergent agents like West Nile, Zika and Chikungunya viruses, or parasites such as Plasmodium and Trypanosoma cruzi in non-endemic regions, for instance.

Screening programmes of the donors are more and more implemented in several Countries, but these cannot prevent completely infections, especially when they are caused by new agents.

Pathogen inactivation (PI) methods might overcome the limits of the screening and different technologies have been set up in the last years.

This review aims to describe the most widely used methods focusing on their efficacy as well as on the preservation integrity of blood components.

Treatment of platelet concentrates and plasma with riboflavin and UV light: Impact in bacterial reduction

OBJECTIVES

Transfusion of hemocomponents is essential for clinical and surgical procedures and therefore their safety has increased. An option for pathogen reduction includes the combination of riboflavin and UV light. To our knowledge, there are no studies in Latin America that demonstrate the effectiveness of the pathogen reduction in hemocomponents. The objective of this work was to evaluate the efficiency of a pathogens reduction system in platelets concentrates (PC) and plasma.

MATERIALS AND METHODS

PC and plasma were contaminated with Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes and Staphylococcus epidermidis at 10⁴ to 10⁶ CFU and subjected to bacterial reduction. After bacterial reduction, hemocomponents were subjected to cultivation of surviving bacteria by automated method and classical colonies quantification. Additionally, quality control testing was performed in order to confirm the integrity of platelets and coagulation laboratory values in plasma before and after bacterial reduction.

RESULTS

The bacterial death in PC/plasma was expressed by Logarithmic Reduction Value as follows: for both strains (E. coli and S. pyogenes) 4/4, 5/5 and 6/6; for K. pneumoniae 2.54/2.23, 2.94/2.22 and 3.44/2.98, for S. epidermidis 4/4, 3.11/5 and 3.23/4.19, for 10⁴, 10⁵ and 10⁶ CFU, respectively. In PC and plasma, platelet count, pH (at 22°C), activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, factor VIII and total proteins (TP) were slightly modified.

CONCLUSIONS

UV light with riboflavin is able to reduce an important number of pathogens in hemocomponents; however, the bacterial reduction is influenced by the nature and quantity of the pathogen.

Towards pathogen inactivation of red blood cells and whole blood targeting viral DNA/RNA: design, technologies, and future prospects for developing countries

Over 110 million units of blood are collected yearly. The need for blood products is greater in developing countries, but so is the risk of contracting a transfusion-transmitted infection. Without efficient donor screening/viral testing and validated pathogen inactivation technology, the risk of transfusion-transmitted infections correlates with the infection rate of the donor population. The World Health Organization has published guidelines on good manufacturing practices in an effort to ensure a strong global standard of transfusion and blood product safety. Sub-Saharan Africa is a high-risk region for malaria, human immunodeficiency virus (HIV), hepatitis B virus and syphilis. Southeast Asia experiences high rates of hepatitis C virus. Areas with a tropical climate have an increased risk of Zika virus, Dengue virus, West Nile virus and Chikungunya, and impoverished countries face economical limitations which hinder efforts to acquire the most modern pathogen inactivation technology. These systems include Mirasol® Pathogen Reduction Technology, INTERCEPT®, and THERAFLEX®. Their procedures use a chemical and ultraviolet or visible light for pathogen inactivation and significantly decrease the threat of pathogen transmission in plasma and platelets. They are licensed for use in Europe and are used in several other countries. The current interest in the blood industry is the development of pathogen inactivation technologies that can treat whole blood (WB) and red blood cell (RBC). The Mirasol system has recently undergone phase III clinical trials for treating WB in Ghana and has demonstrated some efficacy toward malaria inactivation and low risk of adverse effects. A 2nd-generation of the INTERCEPT® S-303 system for WB is currently undergoing a phase III clinical trial. Both methodologies are applicable for WB and components derived from virally reduced WB or RBC.

Mirasol pathogen reduction technology treatment of human whole blood does not induce acute lung injury in mice

In resource-limited settings and in the military theater, fresh human whole blood is commonly transfused, but infectious risks are a concern. Sophisticated molecular testing for potential infectious agents in the whole blood is often unavailable. To address this unmet need, pathogen reduction technology (PRT) has been developed, and it is an effective approach to inactivate a broad range of pathogens found in human blood. However, studies are needed to determine if it is harmful to blood cells and whether these cells could damage the transfused recipient, including the development of acute lung injury/acute respiratory distress syndrome. In this study, we used a commercial PRT system to treat human whole blood that was then transfused into immunodeficient mice, and the development of acute lung injury was determined. In a model of transfusion-related acute lung injury (TRALI), BALB/c SCID mice developed more robust lung injury when challenged with a MHC Class I monoclonal antibody compared to BALB/c wild-type and NOD/SCID mice. Transfusion of control versus Mirasol PRT-treated whole blood (25% blood volume exchange) into BALB/c SCID mice did not produce lung injury at storage day 1. However, mild lung injury at storage days 14 and 21 was observed without significant differences in lung injury measurements between Mirasol PRT-treated and control groups. The mild storage-dependent acute lung injury correlated with trends for increased levels of cell-free hemoglobin that accumulated in both the control and Mirasol PRT-treated groups. Neutrophil extracellular traps were elevated in the plasma of BALB/c SCID mice in the monoclonal antibody TRALI model, but were not different in mice that received exchange transfusions. In conclusion, exchange transfusion of human whole blood into immunodeficient mice produces mild lung injury that is storage-dependent and not related to pathogen reduction treatment.