Pathogen inactivation of Trypanosoma cruzi in plasma and platelet concentrates using riboflavin and ultraviolet light.

BACKGROUND: Emigration of people infected with Trypanosoma cruzi to non-endemic areas has resulted in transfusion transmission to immunocompromised recipients. We studied the feasibility of inactivating T. cruzi using a new technology which utilizes riboflavin as a photosensitizer in combination with UV light, Mirasol PRT. METHODS: One billion T. cruzi organisms and 30 mL of 500 microM riboflavin were added to each of six units of human plasma and six units of platelets. To determine the level of detection of organism, a sample of each unit was cultured in tenfold serial dilutions beginning with 100 billion/250 mL as the starting culture. After 30 min, each unit was illuminated with 5.9 J/cm(2) of UV light (6.24 J/mL). The units were then cultured again in tenfold serial dilutions post-treatment. RESULTS: A 6 log reduction of pathogens was demonstrated in 5 of 6 units of plasma, and a 7 log reduction of pathogens was demonstrated in one unit. A 6 log reduction of pathogens was demonstrated in 3 of 6 units of platelets, a 7 log reduction was demonstrated in 2 of 6 units of platelets, and an 8 log reduction of pathogens was demonstrated in 1 of 6 units. CONCLUSIONS: Mirasol PRT treatment demonstrated an ability to inactivate 5-7 logs of T. cruzi in plasma and platelets.     

White blood cell inactivation after treatment with riboflavin and ultraviolet light

Functional white blood cells (WBCs) in blood components may be responsible for a number of adverse transfusion effects, including transfusion‐associated graft‐versus‐host disease (TA‐GVHD), alloimmunization, and alloimmune platelet (PLT) refractoriness. TA‐GVHD occurs when functional lymphocytes are transfused into a patient who is unable to mount an immune response to the human leukocyte antigen (HLA) due to HLA compatibility or immunosuppression. Alloantibodies against HLA antigens on donor WBCs and PLTs are the major cause of refractoriness to PLT transfusions in patients receiving repeated blood transfusions. Attempts to reduce these undesirable effects have included leukoreduction filters and gamma irradiation. Studies have shown that exposure of PLT concentrates to riboflavin and light (Mirasol pathogen reduction technology [PRT], CaridianBCT Biotechnologies) causes irreparable modifications of nucleic acids that result in inactivation of a wide range of pathogens as well as inhibition of the immunologic responses mediated by WBCs present in PLT concentrates. This article summarizes these studies and also reports on additional findings from the Trial to Reduce Alloimmunization to Platelets (TRAP) and Mirasol Clinical Evaluation (MIRACLE) trials. Data from in vitro studies and this clinical trial suggest that PRT treatment may be as effective as gamma irradiation in preventing TA‐GVHD and more effective than leukoreduction in preventing alloimmunization.     

In vitro quality of single-donor platelets treated with riboflavin and ultraviolet light and stored in platelet storage medium for up to 8 days

BACKGROUND: The Mirasol pathogen reduction technology system is known to increase the activation and metabolic rate of platelets (PLTs). Storage of Mirasol PLTs in PLT storage medium (PSM) has the potential to slow this accelerated PLT storage lesion. We investigated the quality of Mirasol‐treated PLTs stored in either 50% SSP+ or 50% Composol for 8 days. STUDY DESIGN AND METHODS: Single‐donor double hyperconcentrates were divided between control and Mirasol‐treated arms and after treatment were suspended in approximately 50% (vol/vol) SSP+ (n = 8) or Composol (n = 7). In vitro markers of PLT activation and/or apoptosis were measured over an 8‐day storage period. RESULTS: Mirasol treatment resulted in increased spontaneous PLT activation and glycolysis and these effects were worsened when PLTs were treated below a certain volume (150 mL). At higher treatment volumes there were no significant differences between treated units stored in either Composol or SSP+. When low‐volume units were stored in Composol the median pH fell below 6.4 on Day 5 and bicarbonate was undetectable, whereas in SSP+ the median pH value was greater than 6.9 and bicarbonate remained at detectable levels, despite other markers of in vitro function being similar to those of Composol. CONCLUSION: Mirasol treatment of PLTs followed by storage in PSM results in increased PLT activation and metabolism to a level similar to that reported for PLTs treated and stored in plasma. Units treated at a low volume (<150 mL) showed poor in vitro quality.     

Efficacy of apheresis platelets treated with riboflavin and ultraviolet light for pathogen reduction

BACKGROUND: Pathogen reduction technologies for platelet (PLT) components offer a means to address continued viral transmission risks and imperfect bacterial detection systems. The efficacy of apheresis PLTs treated with riboflavin (vitamin B2) plus ultraviolet (UV) light (Mirasol, Navigant Biotechnologies) was investigated in a single-blind, crossover study in comparison to untreated PLTs. STUDY DESIGN AND METHODS: Normal subjects (n = 24) donated PLTs by apheresis on two occasions at least 2 weeks apart. Units were randomized to control or test arms, the latter receiving the addition of 28 mL of 500 micromol per L B2 and exposure to 6.2 J per mL UV light. PLTs were stored for 5 days with biochemical and hematologic analyses performed before and after illumination on Day 0 and at the end of storage. An aliquot of each unit was radiolabeled and returned to determine recovery and survival. RESULTS: The PLT content of treated units was maintained from Day 0 (4.1 x 10(11) +/- 0.4 x 10(11)) to Day 5 (4.0 x 10(11) +/- 0.4 x 10(11)). Treatment with B2 plus UV light was associated with an increase in lactate production with concomitant increases in glucose consumption. pH (control, 7.38 +/- 0.07; test, 7.02 +/- 0.10) was well maintained throughout storage. Recovery of treated PLTs (50.0 +/- 18.9%) was reduced from that of control PLTs (66.5 +/- 13.4%); survival was similarly shortened (104 +/- 26 hr vs. 142 +/- 26 h; p < 0.001). CONCLUSIONS: PLTs treated with B2 plus UV light demonstrate some alterations in in vitro measures but retain in vitro and in vivo capabilities similar to pathogen-reduced and licensed PLT components that have been shown to have useful clinical applicability. The recovery, survival, and metabolic properties of Mirasol PLTs should provide sufficient hemostatic support in thrombocytopenia to justify patient clinical trials.     

Photochemical inactivation of selected viruses and bacteria in platelet concentrates using riboflavin and light

BACKGROUND: A medical device is being developed for the reduction of pathogens in PLT concentrates (PCs). The device uses broadband UV light and the compound riboflavin (vitamin B(2)). STUDY DESIGN AND METHODS: Pathogens were added to single-donor PLTs. After treatment, the infectivity of each pathogen was measured using established biologic assays. In vitro PLT performance was evaluated after treatment and after 5 days of storage using a panel of 10 in-vitro cell quality assays. RESULTS: In studies with viral pathogens, the Pathogen Reduction Technology (PRT) system provided average log reduction factors of 4.46 +/- 0.39 for intracellular HIV, 5.93 +/- 0.20 for cells associated HIV, and 5.19 +/- 0.50 for West Nile virus. For the nonenveloped porcine parvovirus, a reduction factor greater than 5.0 log was observed. Staphylococcus epidermidis and Escherichia coli bacteria were also tested with observed reduction factors to the limits of detection of 4.0 log or greater. PLT cell quality was adequately maintained after treatment and during storage. Although P-selectin expression, glucose consumption, and lactate production increased relative to controls, this was not beyond accepted levels. The pH of treated PCs also decreased slightly relative to control PLTs on Days 1 and 5. CONCLUSION: The data indicate that the device successfully reduced the number of selected pathogens in PCs. Despite the fact that significant differences exist between treated and control in-vitro variables, it is speculated that the clinical effectiveness of both products will not be significantly different, based on comparison to historical data for products in routine clinical use today.     

Evaluating pathogen reduction of Trypanosoma cruzi with riboflavin and ultraviolet light for whole blood

BACKGROUND: Trypanosoma cruzi, the protozoan parasitic agent of Chagas disease, can be transmitted by blood transfusion. In 2007, most US blood banks started screening blood donations for T. cruzi, but the cost and perceived need of the test have been the subject of ongoing discussion. In this study, we evaluated the ability of the Mirasol System (CaridianBCT), which uses riboflavin (RB) and ultraviolet light to inactivate pathogens, to reduce the levels of infectious T. cruzi in whole blood (WB). STUDY DESIGN AND METHODS: WB units were inoculated with 4, 40, 400, and 4000 trypomastigotes/mL. After addition of RB and illumination at various energy levels, the samples were tested for the presence of live parasites by hemoculture. RESULTS: All preillumination samples exhibited T. cruzi growth in hemoculture, while postillumination samples from units containing 4 and 40 trypomastigotes/mL showed no signs of viable parasites after 16 weeks of culture. In contrast, at both 400 and 4000 parasites/mL, two of the three units were positive for viable parasites. CONCLUSIONS: The total log reduction observed for T. cruzi was 3.5 log or greater, but less than 4.5 log. This level of reduction is likely to be orders of magnitude higher than what would be expected in a tainted blood donation, indicating that the Mirasol System could be effective at preventing transfusion of the causative agent of Chagas disease.     

噻唑橙光化学法病原体灭活对红细胞质量的影响

目的评价噻唑橙(TO)光化学法病原体灭活处理对红细胞质量的影响。方法设实验组(n=10):悬浮红细胞经TO光化学法处理后,在4℃储存0、7、14、21、28、35 d时,分别测定pH、溶血率、钾浓度、ATP浓度、2,3-DPG浓度;对照组(n=10):悬浮红细胞未经TO光化学法处理,测定时间、项目同实验组。结果保存过程中实验组pH、2,3-DPG(μmol/gHb)及ATP(μmol/gHb)下降趋势均与对照组差异不大(P0.05),实验组分别从0 d的7.03±0.07、9.43±1.14、4.23±0.58下降到35 d的6.57±0.06、0、2.40±0.49,对照组分别从0 d的6.95±0.09、10.67±1.17、5.18±0.64,下降到35 d的6.57±0.07、0、2.99±0.44;实验组和对照组35 d储存期末ATP浓度分别为0 d时的56.7%和57.7%。;实验组在储存期末,溶血率为(0.27±0.06)%,略高于对照组0.11±0.04%(P0.05),仍满足溶血率≤0.8%的国标要求;钾外漏实验组较对照组增加,35 d时分别为(40.41±2.94)mmol/L和(28.33±3.34)mmol/L(P0.01)。结论 TO光化学法处理对储存过程中的红细胞的质量影响较小。