Human memory T cells with a naive phenotype accumulate with aging and respond to persistent viruses.

The number of naive T cells decreases and susceptibility to new microbial infections increases with age. Here we describe a previously unknown subset of phenotypically naive human CD8(+) T cells that rapidly secreted multiple cytokines in response to persistent viral antigens but differed transcriptionally from memory and effector T cells. The frequency of these CD8(+) T cells, called 'memory T cells with a naive phenotype' (TMNP cells), increased with age and after severe acute infection and inversely correlated with the residual capacity of the immune system to respond to new infections with age. CD8(+) TMNP cells represent a potential new target for the immunotherapy of persistent infections and should be accounted for and subtracted from the naive pool if truly naive T cells are needed to respond to antigens.

Syphilis seroprevalence and incidence in US blood donors from 2020 to 2022.

BACKGROUND: HIV, HBV, and HCV infections for ~60% of the US blood supply are monitored by TTIMS with syphilis added in 2020. STUDY DESIGN AND METHODS: Data were compiled from October 2020 to September 2022. Syphilis prevalence was estimated for allogeneic and directed donors who were consensus positive (CP) and the subset of those with confirmed-active infections (AI). Prevalence and incidence were stratified by demographics for two consecutive 1-year periods, starting October 1, 2020 and for both years combined. Incidence was estimated for repeat donors. Associations between syphilis positivity and other infections were evaluated. RESULTS: Among 14.75 million donations, syphilis prevalence was 28.4/100,000 donations and significantly higher during the second year compared to the first year. Overall, syphilis incidence for the two-year period was 10.8/100,000 person-years. The adjusted odds of a CP infection were 1.18 (95% CI: 1.11, 1.26) times higher in the second year compared to the first, and for AI, 1.22 (95% CI: 1.10, 1.35) times higher in year 2. Highest rates occurred among males, first-time, Black, and younger (ages 18-39) donors, and those in the South US Census region. Syphilis CP donors were 64 (95% CI: 46, 89) times more likely to be HIV CP, and AI donors 77 (95% CI: 52, 114) times more likely to be HIV CP than non-CP donors, when controlling for confounders. SUMMARY/CONCLUSIONS: Syphilis prevalence increased over the study period mirroring national trends reported by CDC and is significantly associated with HIV CP.

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.

Plasma transfusion-transmission of Zika virus in mice and macaques.

BACKGROUND: Zika virus (ZIKV) epidemics with infections in pregnant women are associated with severe neurological disease in newborns. Although an arbovirus, ZIKV is also blood transfusion-transmitted (TT). Greater knowledge of the efficiency of ZIKV TT would aid decisions on testing and pathogen reduction technologies (PRT). STUDY DESIGN AND METHODS: Plasma units from ZIKV RNA-reactive blood donors were used to study infectivity in vitro, in mice, and in macaques. Furthermore, plasma units were subjected to PRT using amotosalen/ultraviolet light A (A/UVA) before transfusion. RESULTS: In vitro infectivity of ZIKV RNA-reactive plasma varied between 100 and 1000 international units (IU) of ZIKV RNA. Immunodeficient mice were more sensitive with as low as 32 IU sufficient to infect 50% of mice. 50-5500 IU of RNA led to TT in macaques using dose escalation of three different RNA-positive, seronegative plasma units. In contrast, RNA-reactive units collected postseroconversion were not infectious in macaques, even at a dose of 9 million IU RNA. After A/UVA PRT, transfusion of plasma containing up to 18 million IU was no longer infectious in vitro and did not result in ZIKV TT in macaques. CONCLUSION: Significant risks of ZIKV TT are likely confined to a relatively short viremic window before seroconversion, and that sensitive nucleic acid amplification testing likely identifies the majority of infectious plasma. PRT was demonstrated to be effective at preventing ZIKV TT. Considering that there is no approved ZIKV vaccine, these data are relevant to mitigate the risk of TT during the future ZIKV outbreaks.

Estimates of SARS-CoV-2 Seroprevalence and Incidence of Primary SARS-CoV-2 Infections Among Blood Donors, by COVID-19 Vaccination Status - United States, April 2021-September 2022.

Changes in testing behaviors and reporting requirements have hampered the ability to estimate the U.S. SARS-CoV-2 incidence (1). Hybrid immunity (immunity derived from both previous infection and vaccination) has been reported to provide better protection than that from infection or vaccination alone (2). To estimate the incidence of infection and the prevalence of infection- or vaccination-induced antibodies (or both), data from a nationwide, longitudinal cohort of blood donors were analyzed. During the second quarter of 2021 (April-June), an estimated 68.4% of persons aged ≥16 years had infection- or vaccination-induced SARS-CoV-2 antibodies, including 47.5% from vaccination alone, 12.0% from infection alone, and 8.9% from both. By the third quarter of 2022 (July-September), 96.4% had SARS-CoV-2 antibodies from previous infection or vaccination, including 22.6% from infection alone and 26.1% from vaccination alone; 47.7% had hybrid immunity. Prevalence of hybrid immunity was lowest among persons aged ≥65 years (36.9%), the group with the highest risk for severe disease if infected, and was highest among those aged 16-29 years (59.6%). Low prevalence of infection-induced and hybrid immunity among older adults reflects the success of public health infection prevention efforts while also highlighting the importance of older adults staying up to date with recommended COVID-19 vaccination, including at least 1 bivalent dose.*,†.

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.

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 yellow fever virus with amotosalen and ultraviolet A light pathogen-reduction technology.

BACKGROUND: The reemergence of yellow fever virus (YFV) in Africa and Brazil, and massive vaccine campaigns triggered to contain the outbreaks, have raised concerns over blood transfusion safety and availability with increased risk of YFV transfusion-transmitted infections (TTIs) by native and vaccine-acquired YFV. Blood donor deferral for 2 to 4 weeks following live attenuated YFV vaccination, and deferral for travel to endemic/epidemic areas, may result in blood donor loss and impact platelet component (PC) stocks. This study investigated the efficacy of INTERCEPT Blood System pathogen reduction (PR) with use of amotosalen and ultraviolet A (UVA) light to inactivate high levels of YFV in PCs. MATERIALS: Four units of apheresis platelets prepared in 35% plasma/65% platelet additive solution (PC-PAS) and 4 units of PC in 100% human plasma (PC-Plasma) were spiked with high infectious titers of YFV (YFV-17D vaccine strain). YFV-17D infectious titers were measured by plaque assay and expressed as plaque-forming units (PFU) before and after amotosalen/UVA treatment to determine log reduction. RESULTS: The mean YFV-17D infectious titers in PC before inactivation were 5.5 ± 0.1 log PFU/mL in PC-PAS and 5.3 ± 0.1 log PFU/mL in PC-Plasma. No infectivity was detected immediately after amotosalen/UVA treatment. CONCLUSION: The amotosalen/UVA PR system inactivated high titers of infectious YFV-17D in PC. This PR technology could reduce the risk of YFV TTI and help secure PC supplies in areas experiencing YFV outbreaks where massive vaccination campaigns are required.

Inactivation of Plasmodium falciparum in whole blood using the amustaline and glutathione pathogen reduction technology.

BACKGROUND: Risk of transfusion-transmitted (TT) malaria is mainly associated with whole blood (WB) or red blood cell (RBC) transfusion. Risk mitigation relies mostly on donor deferral while a limited number of countries perform blood testing, both negatively impacting blood availability. This study investigated the efficacy of the pathogen reduction system using amustaline and glutathione (GSH) to inactivate Plasmodium falciparum in WB. STUDY DESIGN AND METHODS: WB units were spiked with ring stage P. falciparum infected RBCs. Parasite loads were measured in samples at time of infection, after 24 hours at room temperature (RT), and after a 24-hour incubation at RT post-treatment with 0.2 mM amustaline and 2 mM GSH. Serial 10-fold dilutions of the samples were inoculated to RBC cultures and maintained up to 4 weeks. Parasitemia was quantified by cytometry. RESULTS: The P. falciparum viability assay has a limit of detection of a single live parasite per sample. Input parasite titer was >5.7 log10 TCID50 per mL. A 24-hour incubation at RT paused parasite development in controls, but they retained viability and infectivity when tested in culture. In contrast, no infectious parasites were detected in the amustaline/GSH-treated sample after 4 weeks of culture. CONCLUSION: A robust level of P. falciparum inactivation was achieved in WB using amustaline/GSH treatment. Parasite log reduction was >5.7 log10 TCID50 per mL. Development of such a pathogen reduction system may provide an opportunity to reduce the risk of TT malaria and improve blood availability.

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

BACKGROUND: The INTERCEPT Blood System pathogen reduction technology (PRT), which uses amotosalen and ultraviolet A light treatment (amotosalen/UV-PRT), inactivates pathogens in plasma and platelet components (PCs). This review summarizes data describing the inactivation efficacy of amotosalen/UVA-PRT for a broad spectrum of viruses and parasites. METHODS: Twenty-five enveloped viruses, six nonenveloped viruses (NEVs), and four parasites species were evaluated for sensitivity to amotosalen/UVA-PRT. Pathogens were spiked into plasma and PC at high titers. Samples were collected before and after PRT and assessed for infectivity with cell cultures or animal models. Log reduction factors (LRFs) were defined as the difference in infectious titers before and after amotosalen/UV-PRT. RESULTS: LRFs of ≥4.0 log were reported for 19 pathogens in plasma (range, ≥4.0 to ≥7.6), 28 pathogens in PC in platelet additive solution (PC-PAS; ≥4.1-≥7.8), and 14 pathogens in PC in 100% plasma (PC-100%; (≥4.3->8.4). Twenty-five enveloped viruses and two NEVs were sensitive to amotosalen/UV-PRT; LRF ranged from >2.9 to ≥7.6 in plasma, 2.4 or greater to greater than 6.9 in PC-PAS and >3.5 to >6.5 in PC-100%. Infectious titers for four parasites were reduced by >4.0 log in all PC and plasma (≥4.9 to >8.4). CONCLUSION: Amotosalen/UVA-PRT demonstrated effective infectious titer reduction for a broad spectrum of viruses and parasites. This confirms the capacity of this system to reduce the risk of viral and parasitic transfusion-transmitted infections by plasma and PCs in various geographies.

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.

Frequent blood donations alter susceptibility of red blood cells to storage- and stress-induced hemolysis.

BACKGROUND: Frequent whole blood donations increase the prevalence of iron depletion in blood donors, which may subsequently interfere with normal erythropoiesis. The purpose of this study was to evaluate the associations between donation frequency and red blood cell (RBC) storage stability in a racially/ethnically diverse population of blood donors. STUDY DESIGN: Leukoreduced RBC concentrate-derived samples from 13,403 donors were stored for 39 to 42 days (1-6°C) and then evaluated for storage, osmotic, and oxidative hemolysis. Iron status was evaluated by plasma ferritin measurement and self-reported intake of iron supplements. Donation history in the prior 2 years was obtained for each subject. RESULTS: Frequent blood donors enrolled in this study were likely to be white, male, and of older age (56.1 ± 5.0 years). Prior donation intensity was negatively associated with oxidative hemolysis (p < 0.0001) in multivariate analyses correcting for age, sex, and race/ethnicity. Increased plasma ferritin concentration was associated with increased RBC susceptibility to each of the three measures of hemolysis (p < 0.0001 for all), whereas self-reported iron intake was associated with reduced susceptibility to osmotic and oxidative hemolysis (p < 0.0001 for both). CONCLUSIONS: Frequent blood donations may alter the quality of blood components by modulating RBC predisposition to hemolysis. RBCs collected from frequent donors with low ferritin have altered susceptibility to hemolysis. Thus, frequent donation and associated iron loss may alter the quality of stored RBC components collected from iron-deficient donors. Further investigation is necessary to assess posttransfusion safety and efficacy in patients receiving these RBC products.

Intradonor reproducibility and changes in hemolytic variables during red blood cell storage: results of recall phase of the REDS-III RBC-Omics study.

BACKGROUND: Genetic determinants may underlie the susceptibility of red blood cells (RBCs) to hemolyze in vivo and during routine storage. This study characterized the reproducibility and dynamics of in vitro hemolysis variables from a subset of the 13,403 blood donors enrolled in the RBC-Omics study. STUDY DESIGN AND METHODS: RBC-Omics donors with either low or high hemolysis results on 4°C-stored leukoreduced (LR)-RBC samples from enrollment donations stored for 39 to 42 days were recalled 2 to 12 months later to donate LR-RBCs. Samples of stored LR-RBCs from the unit and from transfer bags were evaluated for spontaneous and stress-induced hemolysis at selected storage time points. Intradonor reproducibility of hemolysis variables was evaluated in transfer bags over two donations. Hemolysis data at serial storage time points were generated on LR-RBCs from parent bags and analyzed by site, sex, race/ethnicity, and donation frequency. RESULTS: A total of 664 donors were successfully recalled. Analysis of intradonor reproducibility revealed that osmotic and oxidative hemolysis demonstrated good and moderate reproducibility (Pearson's r = 0.85 and r = 0.53, respectively), while spontaneous hemolysis reproducibility was poor (r = 0.40). Longitudinal hemolysis in parent bags showed large increases over time in spontaneous (508.6%) and oxidative hemolysis (399.8%) and smaller increases in osmotic (9.4%) and mechanical fragility (3.4%; all p < 0.0001). CONCLUSION: Spontaneous hemolysis is poorly reproducible in donors over time and may depend on site processing methods, while oxidative and osmotic hemolysis were reproducible in donors and hence could reflect consistent heritable phenotypes attributable to genetic traits. Spontaneous and oxidative hemolysis increased over time of storage, whereas osmotic and mechanical hemolysis remained relatively stable.

Piloting and implementation of quality assessment and quality control procedures in RBC-Omics: a large multi-center study of red blood cell hemolysis during storage.

BACKGROUND: The major aims of the RBC-Omics study were to evaluate the genomic and metabolomic determinants of spontaneous and stress-induced hemolysis during RBC storage. This study was unique in scale and design to allow evaluation of RBC donations from a sufficient number of donors across the spectrum of race, ethnicity, sex, and donation intensity. Study procedures were carefully piloted, optimized, and controlled to enable high-quality data collection. METHODS: The enrollment goal of 14,000 RBC donors across four centers, with characterization of RBC hemolysis across two testing laboratories, required rigorous piloting and optimization and establishment of a quality assurance (QA) and quality control (QC) program. Optimization of WBC elution from leukoreduction (LR) filters, development and validation of small-volume transfer bags, impact of manufacturing and sample-handling procedures on hemolysis parameters, and testing consistency across laboratories and technicians and over time were part of this quality assurance/quality control program. RESULTS: LR filter elution procedures were optimized for obtaining DNA for analysis. Significant differences between standard and pediatric storage bags led to use of an alternative LR-RBC transfer bag. The impact of sample preparation and freezing methods on metabolomics analyses was evaluated. Proficiency testing monitored and documented testing consistency across laboratories and technicians. CONCLUSION: Piloting and optimization, and establishment of a robust quality assurance/quality control program documented process consistency throughout the study and was essential in executing this large-scale multicenter study. This program supports the validity of the RBC-Omics study results and a sample repository that can be used in future studies.

In vitro evaluation of pathogen inactivated platelet quality: An 8 year experience of routine use in Galicia, Spain.

BACKGROUND: Platelet concentrates (PCs) treated by the pathogen inactivation technology (PI) using amotosalen and UVA illumination (PI-PCs) can be manufactured in additive solutions (PAS-III and PAS-IIIM) or in 100% Plasma. Quality control (QC) is an integral part of the production. We capitalized on our ongoing QC program to capture 8 years-worth of data on parameters related to the quality of 116,214 PI-PCs produced under different manufacturing methods. MATERIALS AND METHODS: Selected in vitro parameters of metabolism, activation, and storage were analyzed for the different manufacturing periods to compare PI-PCs versus conventional PCs (C-PCs) resuspended in different PAS. RESULTS AND DISCUSSION: All BC-PCs met quality standards for pH and dose and residual leucocytes. As expected, storage time correlated with increased lactate, LDH, Annexin V, CD62, sCD40 L levels and decreased glucose and pH. With PAS-IIIM, higher levels of glucose were observed toward the end of shelf life (p < 0.0001) with lower platelet activation markers Annexin V (p = 0.038) and CD62 (p = 0.0006). Following PI implementation, a low expire rate of <0.5% was observed. While a 2.3% mean increase in the production of PCs occurred from 2011 to 2015, the distribution of red blood cell concentrates dropped by 4.4%. A mean incidence of 0.14% for transfusion-related adverse reaction was observed while PI-PCs were distributed, similar to the one observed with C-PCs. Overall, PI-PCs prepared in additive solutions consistently met quality standards. Those prepared in PAS-IIIM appeared to have better retention of in vitro characteristics compared to PAS-III though all demonstrated functionality and clinical effectiveness.

An update on Zika virus infection.

The epidemic history of Zika virus began in 2007, with its emergence in Yap Island in the western Pacific, followed in 2013-14 by a larger epidemic in French Polynesia, south Pacific, where the first severe complications and non-vector-borne transmission of the virus were reported. Zika virus emerged in Brazil in 2015 and was declared a national public health emergency after local researchers and physicians reported an increase in microcephaly cases. In 2016, WHO declared the recent cluster of microcephaly cases and other neurological disorders reported in Brazil a global public health emergency. Similar clusters of microcephaly cases were also observed retrospectively in French Polynesia in 2014. In 2015-16, Zika virus continued its spread to cause outbreaks in the Americas and the Pacific, and the first outbreaks were reported in continental USA, Africa, and southeast Asia. Non-vector-borne transmission was confirmed and Zika virus was established as a cause of severe neurological complications in fetuses, neonates, and adults. This Review focuses on important updates and gaps in the knowledge of Zika virus as of early 2017.

Neuroinvasive West Nile Infection Elicits Elevated and Atypically Polarized T Cell Responses That Promote a Pathogenic Outcome.

Most West Nile virus (WNV) infections are asymptomatic, but some lead to neuroinvasive disease with symptoms ranging from disorientation to paralysis and death. Evidence from animal models suggests that neuroinvasive infections may arise as a consequence of impaired immune protection. However, other data suggest that neurologic symptoms may arise as a consequence of immune mediated damage. We demonstrate that elevated immune responses are present in neuroinvasive disease by directly characterizing WNV-specific T cells in subjects with laboratory documented infections using human histocompatibility leukocyte antigen (HLA) class II tetramers. Subjects with neuroinvasive infections had higher overall numbers of WNV-specific T cells than those with asymptomatic infections. Independent of this, we also observed age related increases in WNV-specific T cell responses. Further analysis revealed that WNV-specific T cell responses included a population of atypically polarized CXCR3+CCR4+CCR6- T cells, whose presence was highly correlated with neuroinvasive disease. Moreover, a higher proportion of WNV-specific T cells in these subjects co-produced interferon-γ and interleukin 4 than those from asymptomatic subjects. More globally, subjects with neuroinvasive infections had reduced numbers of CD4+FoxP3+ Tregs that were CTLA4 positive and exhibited a distinct upregulated transcript profile that was absent in subjects with asymptomatic infections. Thus, subjects with neuroinvasive WNV infections exhibited elevated, dysregulated, and atypically polarized responses, suggesting that immune mediated damage may indeed contribute to pathogenic outcomes.

Inactivation of chikungunya virus in blood components treated with amotosalen/ultraviolet A light or amustaline/glutathione.

BACKGROUND: Chikungunya virus, a mosquito-borne arbovirus, often co-circulates with the Zika, dengue, and yellow fever viruses in Aedes mosquito-infested areas where cases of arbovirus transfusion-transmitted infections have been reported. Building on past experience to help maintain the availability of safe components during major outbreaks of chikungunya virus in La Reunion, Italy, and Thailand and of Zika virus in the Pacific, the Caribbean, and the Americas, pathogen inactivation is a mitigation strategy to reduce the risk of transfusion-transmitted infection. Inactivation of chikungunya virus was investigated for platelets in 100% plasma using amotosalen/ultraviolet A light, and in red blood cells using amustaline/glutathione. STUDY DESIGN AND METHODS: Platelets in 100% plasma and red blood cells (RBCs) were spiked with chikungunya virus. Infectious chikungunya virus titers were measured in contaminated blood products before and after treatment with amotosalen/ultraviolet A light for platelets in 100% plasma and after treatment with amustaline/glutathione for RBCs. Viral infectivity was quantified by plaque assay. RESULTS: The mean chikungunya virus infectivity titers before inactivation were 6.50 log10 plaque-forming units/mL for platelets in 100% plasma and 7.60 log10 plaque-forming units/mL for RBCs. No infectivity was detected after amotosalen/ultraviolet A light or amustaline/glutathione treatment, corresponding to greater than 6.5 log10 plaque-forming units/mL and greater than 7.1 log10 plaque-forming units/mL of inactivation, respectively. CONCLUSION: Robust levels of chikungunya virus inactivation were achieved for platelets in 100% plasma and for RBC components. The licensed amotosalen/ultraviolet A light technology and the amustaline/glutathione pathogen-reduction system under development may provide an opportunity for comprehensive mitigation of the risk of chikungunya virus transfusion-transmitted infection by plasma, platelets, and RBCs.

Blood Gene Signatures of Chagas Cardiomyopathy With or Without Ventricular Dysfunction.

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects 7 million people in Latin American areas of endemicity. About 30% of infected patients will develop chronic Chagas cardiomyopathy (CCC), an inflammatory cardiomyopathy characterized by hypertrophy, fibrosis, and myocarditis. Further studies are necessary to understand the molecular mechanisms of disease progression. Transcriptome analysis has been increasingly used to identify molecular changes associated with disease outcomes. We thus assessed the whole-blood transcriptome of patients with Chagas disease. Microarray analysis was performed on blood samples from 150 subjects, of whom 30 were uninfected control patients and 120 had Chagas disease (1 group had asymptomatic disease, and 2 groups had CCC with either a preserved or reduced left ventricular ejection fraction [LVEF]). Each Chagas disease group displayed distinct gene expression and functional pathway profiles. The most different expression patterns were between CCC groups with a preserved or reduced LVEF. A more stringent analysis indicated that 27 differentially expressed genes, particularly those related to natural killer (NK)/CD8+ T-cell cytotoxicity, separated the 2 groups. NK/CD8+ T-cell cytotoxicity could play a role in determining Chagas disease progression. Understanding genes associated with disease may lead to improved insight into CCC pathogenesis and the identification of prognostic factors for CCC progression.

Molecular detection of Zika virus in blood and RNA load determination during the French Polynesian outbreak.

Zika virus (ZIKV) viremia is reported as low and transient; however, these estimates rely on limited data. We report RNA loads in sera collected from symptomatic patients during the 2013-2014 French Polynesian ZIKV outbreak. We performed molecular detection of ZIKV RNA in sera from 747 patients presenting with suspected acute phase ZIKV infection. Among patients with confirmed infection, we analyzed the duration of viremia, assessed viral RNA loads and recorded the main clinical symptoms. A total of 210/747 (28.1%) sera tested positive using a ZIKV-specific RT-PCR. Viral RNA loads in symptomatic patients that ranged from 5 to 3.7 × 106 copies/mL (mean 9.9 × 104 copies/mL) were not related to a particular clinical presentation, and were significantly lower than those previously obtained from asymptomatic ZIKV infected blood donors. The rate of detection of ZIKV RNA in sera from suspected cases of acute phase ZIKV infection was low. ZIKV RNA loads were lower in symptomatic patients compared to asymptomatic blood donors and were lower than RNA loads usually reported in dengue infections. As there is no abrupt onset of symptoms in ZIKV infections, we suggest that infected patients sought for medical attention when viremia was already decreasing or had resolved.