Platelet concentrates in platelet additive solutions generate less complement activation products during storage than platelets stored in plasma.

BACKGROUND: Platelet transfusions can be associated with adverse reactions, such as febrile non-haemolytic transfusion reaction (FNHTR). It has been suggested that damage-associated molecular patterns (DAMP) and complement play a role in FNHTR. This study investigated the nature of DAMPs and complement activation products contained in platelet concentrates during storage, with a specific focus on different platelet storage solutions. MATERIALS AND METHODS: Buffy coats (BC) from healthy donors were pooled (15 BC per pool) and divided into three groups of the same volume. After addition of different storage solutions (plasma, platelet additive solutions [PAS]-C or PAS-E; n=6 for each group), BC pools were processed to platelet concentrates (PC). Leukoreduced PCs were stored on a shaking bed at 20-24°C and sampled on days 1, 2, 6 and 8 after collection for selected quality parameters: platelet activation, DAMPs (High Mobility Group Box 1 [HMGB1], nucleosomes), and complement activation products. RESULTS: During storage, equal levels of free nucleosomes and increasing concentrations of HMGB1 were present in all groups. Complement activation was observed in all PC. However, by day 8, the use of PAS had reduced C3b/c levels by approximately 90% and C4b/c levels by approximately 65%. DISCUSSION: Nucleosomes and HMGB1 were present in PCs prepared in plasma and PAS. Complement was activated during storage of platelets in plasma and in PAS. The use of PAS is associated with a lower amount of complement activation products due to the dilution of plasma by PAS . Therefore, PC in PAS have less complement activation products than platelets stored in plasma. These proinflammatory mediators in PC might induce FNHTR.

On the Use of Buffy or Whole Blood for Obtaining DNA of High Quality and Functionality: What Is the Best Option?

Human biobanks are collections of biological samples and health information that allow the organization of biomedical research for upgrading the knowledge of human disorders from different diseases (cancer, allergies, rare diseases, etc.), and reach real answers for diagnosis and treatment. A wide range of samples can be stored in these biorepositories such as hair, nails, urine, tissue, whole blood, red blood cells, buffy coat, plasma, serum, DNA, and RNA. Among these, buffy coat and whole blood are widely used by researchers because they can obtain DNA and RNA from these matrices. Some preliminary studies have been performed on animals to evaluate the quality and functionality of the nucleic acids obtained from some of these matrices, although more in-depth studies are needed in this area. In this study, blood samples extracted by venipuncture from 30 healthy volunteers were used to obtain DNA from buffy coat and whole blood. The purity and integrity of the nucleic acids obtained were assessed by spectrophotometry, fluorimetry, and agarose electrophoresis, and functionality was assessed by PCR and real-time PCR. Another aspect tested in this study was based on the comparison between short-term and long-term storage at -80°C and fresh samples from both matrices to evaluate the storage conditions at the biobank. Results showed differences in the yield obtained from both matrices as a function of the storage time, although the functionality of all the obtained DNA remained intact.

Hemozoin Pigment: An Important Tool for Low Parasitemic Malarial Diagnosis.

Low parasitemic condition in malaria remains a diagnostic challenge; as the available diagnostic methods failed to detect. Currently, hemozoin (Hz) pigment is gaining attention in the diagnosis of malaria. The major drawback is ease of detection of Hz in routine practice. A pilot study was conducted to evaluate the role of Hz pigment and to compare the performance of quantitative buffy coat assay (QBC) and PCR in such conditions. Clinically suspected cases of malaria were examined by both Giemsa stain and immunochromatographic test (ICT). Samples positive by ICT and negative by Giemsa stain were further examined by nested PCR targeting 18S rRNA and QBC for the presence of malaria parasites and pigments. Thirty blood samples fulfilled the inclusion criteria out of which 23 were Plasmodium vivax (Pv), 4 Plasmodium falciparum (Pf), and 3 mixed (Pv and Pf) by immunochromatographic test. Twenty-one out of 30 (70%) were positive by nested PCR in comparison to 25/30 (83%) by QBC. Samples containing both malaria parasites and Hz pigment by QBC completely showed concordance with the PCR result. However, 61% of total samples containing only Hz pigment were observed positive by PCR. Hz pigment remains an important tool for malaria diagnosis. Identification of leukocytes containing pigments by QBC not only indicates recent malarial infections but also puts light on severity of the disease. QBC assay is a rapid, highly sensitive, and cost-effective method to detect malaria parasites and Hz pigment especially in low parasitemic conditions.

Whole blood treated with riboflavin and ultraviolet light: quality assessment of all blood components produced by the buffy coat method.

BACKGROUND: Pathogen inactivation (PI) technologies are currently licensed for use with platelet (PLT) and plasma components. Treatment of whole blood (WB) would be of benefit to the blood banking community by saving time and costs compared to individual component treatment. However, no paired, pool-and-split study directly assessing the impact of WB PI on the subsequently produced components has yet been reported. STUDY DESIGN AND METHODS: In a "pool-and-split" study, WB either was treated with riboflavin and ultraviolet (UV) light or was kept untreated as control. The buffy coat (BC) method produced plasma, PLT, and red blood cell (RBC) components. PLT units arising from the untreated WB study arm were treated with riboflavin and UV light on day of production and compared to PLT concentrates (PCs) produced from the treated WB units. A panel of common in vitro variables for the three types of components was used to monitor quality throughout their respective storage periods. RESULTS: PCs derived from the WB PI treatment were of significantly better quality than treated PLT components for most variables. RBCs produced from the WB treatment deteriorated earlier during storage than untreated units. Plasma components showed a 3% to 44% loss in activity for several clotting factors. CONCLUSION: Treatment of WB with riboflavin and UV before production of components by the BC method shows a negative impact on all three blood components. PLT units produced from PI-treated WB exhibited less damage compared to PLT component treatment.

Superiority of the buffy coat over serum or plasma for the detection of Alkhumra virus RNA using real time RT-PCR.

RT-PCR to detect Alkhumra virus (ALKV) RNA in plasma or serum has been the standard practice to confirm this infection in the first seven days of illness. In this study, RT-PCR detection of viral RNA from the plasma, serum, and buffy coat (BC) was compared to virus isolation. Plasma, serum, and BC were obtained from seven patients with clinically suspected ALKV infection in Najran, Saudi Arabia. Baby hamster kidney (BHK-21) and rhesus monkey kidney (LLC-MK2) cell culture monolayers were used for virus isolation. Real-time RT-PCR was used to confirm ALKV infection and to detect viral RNA directly from plasma, serum, and BC. ALKV was isolated from five of the seven patients. The virus was isolated from all three specimen types (plasma, serum, and BC) of the five confirmed patients. ALKV RNA was detected directly by RT-PCR in BC in all five (100%) culture-positive patients and in plasma or serum in only four (80%) of the five patients. Three of the five patients for whom ALKV RNA was detected in BC also had detectable viral RNA in plasma and serum. In the remaining two patients with detectable ALKV RNA in the BC, the plasma was positive but the serum was negative in one patient, whereas the serum was positive and the plasma was negative in the other patient. The use of real-time RT-PCR to detect ALKV RNA in the BC was superior to using plasma and serum and equivalent to virus isolation.

Preparation of platelet concentrates.

Platelets are specialized blood cells that play central roles in physiologic and pathologic processes of hemostasis, wound healing, host defense, thrombosis, inflammation, and tumor metastasis. Activation of platelets is crucial for platelet function that includes a complex interplay of adhesion, signaling molecules, and release of bioactive factors. Transfusion of platelet concentrates is an important treatment component for thrombocytopenia and bleeding. Recent progress in high-throughput mRNA and protein profiling techniques has advanced the understanding of platelet biological functions toward identifying novel platelet-expressed and secreted proteins, analyzing functional changes between normal and pathologic states, and determining the effects of processing and storage on platelet concentrates for transfusion. It is important to understand the different standard methods of platelet preparation and how they differ from the perspective for use as research samples in clinical chemistry. Two simple methods are described here for the preparation of research-scale platelet samples from whole blood, and detailed notes are provided about the methods used for the preparation of platelet concentrates for transfusion.

Genetic structure of native circumpolar populations based on autosomal, mitochondrial, and Y chromosome DNA markers.

This study investigates the genetic structure of the present-day inhabitants of Beringia in order to answer questions concerning their origins and evolution. According to recent studies, the ancestors of Native Americans paused for a time in Beringia, during which they differentiated genetically from other Asians before peopling the New World. Furthermore, the Koryaks of Kamchatka share a "ubiquitous" allele (D9S1120) with Native Americans, indicating they may have descended from the same ancestral Beringian population that gave rise to the New World founders. Our results show that a genetic barrier exists between Kamchatkans (Koryaks and Even) and Bering Island inhabitants (Aleuts, mixed Aleuts, and Russians), based on Analysis of Molecular Variance (AMOVA) and structure analysis of nine autosomal short tandem repeats (STRs). This is supported by mitochondrial DNA evidence, but not by analysis of Y chromosome markers, as recent non-native male admixture into the region appears to have partially obscured ancient population relationships. Our study indicates that while Aleuts are descended from the original New World founders, the Koryaks are unlikely to represent a Beringian remnant of the ancestral population that gave rise to Native Americans. They are instead, like the Even, more recent arrivals to Kamchatka from interior Siberia, and the "ubiquitous" allele in Koryaks may result from recent gene flow from Chukotka. Genbank accession numbers for mtDNA sequences: GQ922935-GQ922973.