Donors with repeated blood product discards for filtration problems, clots or hemolysis: Causes and follow-up.

INTRODUCTION: Sanquin donor medicine department is informed when donations or their components are rejected. This can occur isolated or frequently. It is undesirable because the donations cannot be used and there may be an underlying medical cause. Based on regional approaches, a uniform procedure was developed. METHODS: Information about whole blood, plasma- plateletpheresis donations from which one or more components were rejected for filtration time (>2 h), hemolysis or clots were extracted from blood bank information system. After rejection of two successive components or donations or total ≥3 the donor is contacted. Depending on the medical history and investigation by the family doctor, the donor carrier is re-evaluated. We looked for the causes of the discarded products and performed a survey among blood services regarding polices with discarded products. RESULTS: One or more components from 1742 of about 2.2 million successful donations (0.08%) were rejected. The highest percentage of rejection was seen in plateletpheresis (1.5%), all for clots. No underlying medical causes were found. 24 whole blood donors were found to have sickle cell trait (SCT) and were permanently deferred. The policies for follow-up after discarded products or acceptance of SCT donors vary between the 16 blood banks. Six organizations do not follow-up donors and seven accept SCT for blood or plasma donation. CONCLUSION: Informing donors with repeated discarded products avoids the non-use of donations. Causes of repeated discarded products can be found by follow-up of donors. The results of the survey indicate a large discrepancy in policies applied worldwide.

Isohemagglutinin titration in pooled and apheresis platelets.

BACKGROUND: Platelet inventory constraints necessitate ABO-incompatible platelet transfusion. Many minimize the hemolytic impact by confirming low titre (LT) donor isohemagglutinins. This process is costly. Pathogen-reduced platelets (PRP) in platelet additive solutions (PAS) will dilute plasma and decrease high-titre isohemagglutinins (HT). We determined the proportion of HT platelets and incompatible transfusions for units suspended in plasma to reassess the need for titres following introduction of PRP/PAS. STUDY DESIGN AND METHODS: Our titre method is manual tube (1:50) dilution of platelet supernatant from apheresis or whole blood derived buffy coat pools suspended in plasma, tested with A1/B red cells. Testing included 49,058 pooled and 11,738 apheresis platelets over 4 years. The HT proportion, rate of out-of-group transfusions, and hemolytic reactions were determined. The impact of PAS dilution was estimated. RESULTS: Totally 60,796 platelet units were tested. Group O pooled and group B apheresis platelets had HT in 6.6% and 5.7%, respectively. Group A pooled and apheresis platelets included 2% with HT. Approximately 25% of platelets transfused were ABO-incompatible and no hemolytic reactions were reported. Based on the proportions of PAS-E and plasma for PRP platelets, plasma from each donor comprises 11 mL (6% of total volume) vs 20-257 mL in untreated pools. PAS-E will replace and dilute residual plasma by at least 50%. DISCUSSION: Rare platelet pools may demonstrate HT. PRP platelets with PAS will reduce titres and may abrogate the need for titration. A strategy of group specific transfusion or transfusion of group A PRP platelet transfusions may be a safe alternative.

Donor complication rates in whole blood, plasma and platelet donors: Age versus experience.

BACKGROUND: Many blood banks use upper age limits for donors out of concern for a higher donor complication rate in older donors. Experienced donors are known to have lower donor complication rates, and older donors are often more experienced, confounding the effect of age on donor complication rate. STUDY DESIGN AND METHODS: We studied donor complication rates in whole blood, plasma, and plateletpheresis donors from 2012 to 2022. Donor complication rates were compared between age groups in inexperienced (<20th donation) and experienced (≥20th donation) donors. In addition to this direct comparison, we made use of logistic regression with finer-grained experience groups, to further quantify the effects of age, experience and other factors on donor complication rate. RESULTS: While overall rate of vasovagal reaction was lower, rate of moderate/severe vasovagal syncope was highest in 70-79 year donors, however, only reached significance for plasma donors. Furthermore, rates of failed stab were highest in this age group. Hematoma rate showed a U-shaped pattern with regard to age, where the rate was not higher in the 70-79 year age group than in the 18-23 year age group. Pain decreased with age, however, rates were higher in the 70-79 year age group than in the 65-69 year age group. DISCUSSION: When properly accounting for donor experience, donor complication rate profiles clearly change with age. The increased risk for moderate/severe vasovagal syncope in older donors should be clearly communicated. Extra caution is needed if these donors are accepted for first-time donations.

Evaluation of platelets componentized with the Reveos Automated Blood Processing System and stored for 7 days at room temperature in a non-Di(2-ethylhexyl) phthalate (DEHP) platelet pooling set.

BACKGROUND: Platelet concentrates (PCs) used for transfusion can be produced by apheresis or derived from whole blood (WB). The Reveos device is the first US Food and Drug Administration-approved automated blood processing system that can produce PCs. In this work, we evaluated the quality and function of Reveos-collected PCs stored for 7 days at room temperature. STUDY DESIGN AND METHODS: WB was collected from healthy donors and componentized on the day of collection (Fresh) or after an overnight hold (Overnight). PCs were produced (n = 7 Fresh; n = 6 Overnight), stored at room temperature in plasma, and evaluated on days 1 and 7 for quality metrics, platelet activation, clot formation, and aggregation response. RESULTS: Platelet count was comparable between Fresh and Overnight PCs. A drop in pH was reported in Fresh day 7 PCs (p < .001, vs. day 1) but not in Overnight. Overnight units displayed the lowest levels of P-selectin expression (p = .0008, vs. day 7 Fresh). Reduced clot strength and increased lysis were observed in both Fresh and Overnight units on day 7 (vs. day 1). Overnight-hold PCs resulted in the highest clot strength on day 7 (p = .0084, vs. Fresh). No differences in aggregation were reported between groups. CONCLUSION: Reveos-processed PCs produced from overnight-hold WB performed better in hemostatic function assays and displayed reduced activation compared to fresh WB-derived PCs, although both PC groups maintained platelet quality throughout storage. Utilization of overnight WB for PC preparation with Reveos holds promise as an alternative method of producing platelets for transfusion purposes.

Temporal dynamics of in vitro hemostatic function in platelets cryopreserved using a novel approach for rapid issuance.

BACKGROUND: Current procedures for thawing and issuing of cryopreserved platelets (CPPs) are laborious and have remained challenging in emergency settings such as blood banks and military operations. In this prospective study, a novel processing method designed to facilitate the rapid issuance of CPPs with no postthaw handling required was developed and functionally characterized in parallel with standard CPPs manufactured. STUDY DESIGN AND METHODS: Double-dose plateletpheresis units (n = 42) were cryopreserved at -80°C in 5%-6% dimethyl sulfoxide to produce matched pairs thawed successively over a 27-month period for comparison between two processing arms. In contrast to the standard CPPs manufactured as standalone units, platelets were frozen in tandem with resuspending plasma in a distinct partition as a single unit in the novel method, herein referred to as tandem CPPs. Postthaw (PT) CPPs from both arms were assessed at PT0-, 12-, and 24-h to measure platelet recovery, R-time (time to clot initiation; min), and maximum amplitude (MA; clot strength; mm) using thromboelastography. RESULTS: In the overall dataset, mean platelet recovery was higher (p < .0005) for tandem CPPs (83.9%) compared with standard CPPs (73.3%) at PT0; mean R-times were faster (p < .0005) for tandem CPPs (2.5-3.6 min) compared with standard CPPs (3.0-3.8 min); mean MA was higher for tandem CPPs (57.8-59.5 mm) compared with standard CPPs (52.1-55.8 mm) at each postthaw time point (p < .05). CONCLUSION: Robust temporal dynamics of superior hemostatic functionality were established for tandem CPPs over extended cryopreservation up to 27 months and 24 h of postthaw storage.

Aggregates in apheresis-derived platelet concentrates: A 5-year single-centre experience.

BACKGROUND AND OBJECTIVES: The phenomenon of aggregates in apheresis-derived platelet concentrates (APCs) has not yet been fully elucidated. Initially, visible aggregates (IVA) usually dissolve within 24 h after collection, but some persist till the end of the shelf life (persistent aggregates, PA). A study conducted at the Croatian Institute of Transfusion Medicine aimed to identify factors that influence the aggregate occurrence in APCs. MATERIALS AND METHODS: We conducted a cross-sectional study for the 2018-2022 period and collected data on APCs with IVA. We analysed APCs discarded due to PA separately for two apheresis technologies and compared them to the control group. RESULTS: Significantly more donations were discarded in the IVA group compared with the control group and total number of discarded APCs. A total of 205 APCs were discarded due to PA (14.7% of IVA APCs and 1.27% of all APCs collected). Amicus APCs with PA had a significantly lower platelet count and mean platelet volume. They were obtained by procedures with less anticoagulant used. In contrast to Amicus APCs, Haemonetics APCs with PA had a significantly higher platelet count. None of the donor-related factors examined was predictive of PA. CONCLUSION: APCs with IVA are more often discarded, not only due to aggregates, but also for impairment of other quality control parameters. Type of apheresis technology, being one of the most common risk factors for IVA, was not confirmed as the main risk factor for PA. There seem to be some donor-related causal factors.

Analysis of erythrocyte and iron study data among plateletpheresis donors in Hangzhou, China.

BACKGROUND: The purpose of this study is to obtain the iron parameters level of blood donors and the population who need to pay attention to iron parameters level in this area. METHODS: A total of 993 plateletpheresis donors were included in this study, including 798 males and 195 females. The results of erythrocyte and iron parameters of blood donors were compared and analyzed in different groups according to the gender, age and number of blood donations. RESULT: The proportion of men and women with low serum ferritin (SF) levels was 10.8 % and 27.7 %, respectively. The mean levels of serum iron (SI), SF, transferrin saturation (Tfs), hemoglobin (Hb) and hematocrit (HCT) of male blood donors decreased with the increase of age groups, but there was no significant statistical difference between the results of female blood donors. The level of SI, SF, Tfs, Hb and HCT of male donors decreased with the increase of blood donations in the past year, while TRF and TIBC increased. The level of Hb, HCT and SF of female donors showed no significant downward trend, while the levels of TRF increased with increasing donations in the past year, excluding first-time donors. The SI of female donors trended down, and TIBC trended up with increasing donations. CONCLUSION: Blood collection institutions need to focus on iron parameters levels in older and frequent male donors, and young fertile female donors.

Comparison of Therapeutic Effect of Apheresis Platelets and Buffy Coat-Derived Platelet Concentrates.

BACKGROUND: The study aimed to investigate the difference in clinical efficacy between apheresis platelets and buffy coat-derived platelet concentrates infusion in patients with hematological diseases. METHODS: A total of 218 patients with hematological diseases were enrolled in Xi'an Central Hospital, from January 2023 to October 2023, and randomly divided into two groups: 109 patients were treated with apheresis platelet transfusion (AP group) and 109 patients with buffy coat derived platelet concentrates (BC-PC group). Platelet counts were measured before and 24 hours after transfusion, and the corrected platelet ascending number (CCI) and platelet recovery rate (PPR) were calculated. The clinical efficacy and blood transfusion reaction were observed. RESULTS: After 24 hours of platelet transfusion, there was no significant difference in the platelet count between the AP and BC-PC groups (p > 0.05). However, CCI and PPR significantly differed between the two groups (p < 0.05). Moreover, the incidence of transfusion reaction in the AP group was significantly lower than in the BC-PC group. CONCLUSIONS: The clinical efficacy of buffy coat-derived platelet concentrates is lower than that of apheresis platelets, but it can also improve the patient's condition and quality of life. Therefore, clinicians could rationally use BC-PC, according to the actual situation of the patients.

Evaluation of a scoring system for vein suitability in platelet apheresis donors.

INTRODUCTION: Donor vein assessment for the selection of good quality veins is crucial for a successful apheresis procedure. This study intends to find out the effectiveness of a vein assessment scoring tool (VST) used and found to be effective in selecting whole blood donors to reduce the difficulty in identifying good quality veins for the plateletpheresis procedure. MATERIALS AND METHODS: This was a prospective observational study on platelet apheresis donors with the application of a VST consisting of three vein descriptor parameters (vein visibility, vein palpability, and vein size) with 5 Likert-type responses constituting a score of 0-12 for each arm. Two vein assessors independently evaluated the vein in both arms and marked their responses blinded from each other as well from the principal investigator. The scores were then calculated and analyzed at the end of the study for their association with phlebotomy and procedural outcomes. RESULTS: A total of 190 donors were recruited. The mean scores for the arms with successful and failed phlebotomy were 9.1 and 9.4 (SD 2.3), respectively. The intra-class correlation Alpha Cronbach value was 0.834 and 0.837 for total scoring in the left arm and right arm, respectively, between the two assessors. Scores neither showed a correlation with other outcomes like low flow alarms, hematoma formation, number of phlebotomy attempts, and procedure completion. CONCLUSION: The study showed that the vein score tool did not truly predict the phlebotomy outcome in apheresis donors, though there was a good degree of inter-assessor reliability.

The role of sodium citrate during extended cold storage of platelets in platelet additive solutions.

BACKGROUND: Cold-stored platelets are increasingly being used to treat bleeding. Differences in manufacturing processes and storage solutions can affect platelet quality and may influence the shelf life of cold-stored platelets. PAS-E and PAS-F are approved platelet additive solutions (PAS) in Europe and Australia, or the United States respectively. Comparative data are required to facilitate international transferability of laboratory and clinical data. STUDY DESIGN AND METHODS: Single apheresis platelets from matched donors (n = 8) were collected using the Trima apheresis platform and resuspended in either 40% plasma/60% PAS-E or 40% plasma/60% PAS-F. In a secondary study, platelets in PAS-F were supplemented with sodium citrate, to match the concentration in PAS-E. Components were refrigerated (2-6°C) and tested over 21 days. RESULTS: Cold-stored platelets in PAS-F had a lower pH, a greater propensity to form visible (and micro-) aggregates, and higher activation markers compared to PAS-E. These differences were most pronounced during extended storage (14-21 days). While the functional capacity of cold-stored platelets was similar, the PAS-F group displayed minor improvements in ADP-induced aggregation and TEG parameters (R-time, angle). Supplementation of PAS-F with 11 mM sodium citrate improved the platelet content, maintained the pH above specifications and prevented aggregate formation. DISCUSSION: In vitro parameters were similar during short-term cold storage of platelets in PAS-E and PAS-F. Storage in PAS-F beyond 14 days resulted in poorer metabolic and activation parameters. However, the functional capacity was maintained, or even enhanced. The presence of sodium citrate may be an important constituent in PAS for extended cold storage of platelets.

Comparison of platelet quality and function across apheresis collection platforms.

BACKGROUND: Platelet concentrates (PLT) can be manufactured using a combination of apheresis collection devices and suspension media (plasma or platelet additive solution (PAS)). It is unclear how platelet quality and hemostatic function differ across the current in-use manufacturing methods in the United States. The objective of this study was therefore to compare baseline function of PLT collected using different apheresis collection platforms and storage media. STUDY DESIGN AND METHODS: PLT were collected at two sites with identical protocols (N = 5 per site, N = 10 total per group) on the MCS® + 9000 (Haemonetics; "MCS"), the Trima Accel® 7 (Terumo; "Trima"), and the Amicus Cell Separator (Fresenius Kabi, "Amicus"). MCS PLT were collected into plasma while Trima and Amicus PLT were collected into plasma or PAS (Trima into Isoplate and Amicus into InterSol; yielding groups "TP", "TI" and "AP", "AI", respectively). PLT units were sampled 1 h after collection and assayed to compare cellular counts, biochemistry, and hemostatic function. RESULTS: Differences in biochemistry were most evident between plasma and PAS groups, as anticipated. MCS and TP had the highest clot strength as assessed by viscoelastometry. AI had the lowest thrombin generation capacity. Both TP and TI had the highest responses on platelet aggregometry. AI had the greatest number of microparticles. DISCUSSION: Platelet quality and function differ among collection platforms at baseline. MCS and Trima platelets overall appear to trend toward higher hemostatic function. Future investigations will assess how these differences change throughout storage, and if these in vitro measures are clinically relevant.

Risk factors for T-cell lymphopenia in frequent platelet donors: The BEST collaborative study.

BACKGROUND: Severe T-cell lymphopenia of uncertain clinical significance has been observed in frequent apheresis platelet donors. Two commonly used plateletpheresis instruments are the Trima Accel, which uses a leukoreduction system (LRS) chamber to trap leukocytes and the Fenwal Amicus, which does not use an LRS chamber. STUDY DESIGN AND METHODS: We performed an international, multicenter, observational study comparing T-cell populations in frequent platelet donors collected exclusively using the Trima instrument (n = 131) or the Amicus instrument (n = 77). Age- and sex-matched whole blood donors (n = 126) served as controls. RESULTS: CD4+ T-cell counts <200 cells/µL were found in 9.9% of frequent Trima (LRS+) platelet donors, 4.4% of frequent Amicus (LRS-) platelet donors, and 0 whole blood donors (p < .0001). CD4+ T-cell counts <200 cells/µL were only seen in platelet donors with ≥200 lifetime donations. In multivariable analysis, age, lifetime donations, and instrument (Trima vs. Amicus) were independent risk factors for lymphopenia. In 40 Trima platelet donors, a plasma rinseback procedure was routinely performed following platelet collections. No Trima platelet donors receiving plasma rinseback had a CD4+ T-cell count <200 cells/µL versus 13/91 Trima platelet donors not receiving plasma rinseback (p = .01). DISCUSSION: Recurrent bulk lymphocyte removal appears to contribute to the development of T-cell lymphopenia in frequent, long-term platelet donors. Lymphopenia is more common when an LRS chamber is used during platelet collection but can occur without an LRS chamber. Blood centers using LRS chambers can mitigate donor lymphopenia by performing plasma rinseback.

Young apheresis platelet donors show significant and sustained growth over the last decade in the US, 2010-2019: A favorable sign of the resiliency of the platelet supply.

BACKGROUND: Platelet demand continues to rise and US hospitals frequently face shortages. The peak median age of apheresis platelet donors (APD) is believed to have increased over the last decade, raising concerns that the APD base is not being adequately replenished with young donors. STUDY DESIGN/METHODS: American Red Cross (ARC) apheresis platelet collections were evaluated from calendar years 2010 through 2019. APD, products per procedure/split rate (PPP) and donation frequencies were stratified into age groups. RESULTS/FINDINGS: The number of unique APD from calendar year 2010 through 2019 in the ARC donor pool increased from 87,573 to 115,372 donors, representing a 31.7% overall growth. Donors in the 16-40 year-old (y) age group increased by 78.8% overall, with the largest absolute increases seen in the 26-30 y (4852 donors, 99.9% growth), followed by the 31-35 y (3991, 94.1%) group. Donors aged 56+ increased by 50.4% overall, with the largest increase seen in the 66-70 y (5988 donors, 108.1% growth) group. Middle-aged donors, aged 41-55 y, demonstrated a decrease of 16.5%. Over the last decade, the youngest age groups (16-40 y) comprised 61.3% of first-time donors (FTD). Annual donation frequency increased with increasing age and PPP. The highest donation frequencies were seen in the oldest age groups. CONCLUSION: Although the peak median age of APD increased over the study period, relative contribution of the 16-40 y APD base also increased. Older donors exhibited the highest donation frequencies and thus contributed the largest volume of apheresis platelet units. Platelet donor activity declined in the middle age (41-55 y) group.

'Ironing out the risk': Assessing the effect of plateletpheresis donation frequency on iron stores in South-Asian male donors.

BACKGROUND AND OBJECTIVES: Repeated blood donation is a well-known cause of iron deficiency among donors. However, present scientific literature lacks comprehensive evidence regarding the impact of regular plateletpheresis procedures on body iron reserves. In this study, we aimed to detect and correlate iron deficiency (using iron indices) with the frequency of platelet donations. Additionally, we also analysed the correlation between other iron and haematological indices with serum ferritin to determine cost-effective parameters that may serve as an initial screening approach to determine which donors should be subjected to serum ferritin testing. MATERIALS AND METHODS: A total of 180 male participants from our platelet donor registry were enrolled in this observational cross-sectional study. Enrolment questionnaires were administered to eligible donors, and biological samples were collected during plateletpheresis donation. Biological tests such as complete blood count, reticulocyte indices, iron indices, vitamin B12 and folate were performed. RESULTS: Donors with ≥12 donations per year showed the highest prevalence of low ferritin (serum ferritin: 15-30 ng/mL) and absent iron stores (serum ferritin <15 ng/mL) (41.3% and 26.7%, respectively). Ferritin showed a significant negative correlation with recent (r = -0.346) and lifetime donations (r = -0.196). The efficacy of other indices for identifying iron depletion was much better using a serum ferritin value <15 ng/mL. CONCLUSION: Regular plateletpheresis donations can lead to varying severities of non-anaemic iron deficiency. Blood centres must regularly monitor frequent plateletpheresis donors (especially donors with more than 11 donations in a calendar year) and ideally maintain their serum ferritin above 30 ng/mL.

A multivariate analysis of the risk of iron deficiency in plateletpheresis donors based on logistic regression.

BACKGROUND: The purpose of this study was to analyze the application of individual factors, blood cell related indicators, and blood donation frequency in predicting the risk of iron deficiency of plateletpheresis donors. METHODS: A total of 801 plateletpheresis donors were included in this study. The relationship between risk factors and iron deficiency was retrospectively analyzed by univariate analysis and logistic regression analysis. The application of Hb, MCHC, RDW-CV and blood donation frequency combined prediction of iron deficiency risk among plateletpheresis donors was evaluated. RESULT: The rate of iron deficiency in this study was 31.5 % (241/766). The age, gender (the ratio of male donors), red blood cell related indicators, blood donation frequency were statistically different between the normal and iron deficiency group (all P < 0.05). Age, gender, the reciprocal of Hb and MCHC, RDW-CV, total number of blood donation and number of plateletpheresis donation in the past year, these indicators to predict the risk of iron deficiency area under the curve (AUC) were 0.558, 0.672, 0.785, 0.717, 0.599, 0.621, 0.646, respectively. The AUC of these indicators combined to predict the risk of iron deficiency was 0.877, higher than all single indicators. The sensitivity and specificity of these indicators combined in prediction of iron deficiency were 88.89 % and 81.57 %, respectively. CONCLUSION: Age, gender, the reciprocal of Hb and MCHC, RDV-CV, blood donation frequency are associated with the risk of iron deficiency in plateletpheresis donors. The combination of these indicators has high value in predicting the risk of iron deficiency.

Knowledge and attitudes of apheresis donors regarding apheresis blood donation.

BACKGROUND: Demand for apheresis blood donation has increased with the widening of the use of blood transfusion and the decrease in the donor pool. The knowledge level of apheresis donors, their attitudes such as donating again and recommending others to donate via apheresis are important in meeting this demand. OBJECTIVE: This analytical cross-sectional study was conducted with 182 plateletpheresis donors to determine their knowledge and attitudes regarding apheresis blood donation. MATERIAL AND METHODS: Participants were asked 34 questions (which were prepared based on the literature and perfected by expert opinion and pre-administration) to determine their level of knowledge regarding apheresis. A value of 1 point was assigned for each 'correct' answer and 0 points for 'wrong' and 'do not know' answers. Participants' total level of knowledge scores was formulated to have a value between 0 and 100 (i.e., the score of each group was divided into the number of question and multiplied by 100). Participant attitudes were evaluated based on responses to 14 questions using a 5-point Likert questionnaire. RESULTS: Total knowledge scores regarding apheresis were moderate (55 ± 15.2). Those who were educated above the university level (compared to primary school and less, middle and high-school education levels) had higher level of knowledge scores regarding apheresis. In general, participants had a positive attitude regarding the importance and effects of apheresis blood donation. Those with the following characteristics had a positive attitude (p < 0.05) regarding the importance of apheresis blood donation: female (compared to men), single (compared to married), 18-33 years of age (compared to 34-49 and 50-65 years of age groups, with an above-university level of education (compared to primary school and less, middle and high-school education levels), informed regarding apheresis blood donation, first-time donors and donors to unknown recipients. CONCLUSION: Study participants demonstrated a moderate level of knowledge and positive attitude regarding the importance of apheresis blood donation. Thus, to enhance attitudes on the procedure and reduce the risk of recipient infections, blood donors should be better informed regarding apheresis blood donation.

A method based on plateletpheresis to obtain functional platelet, CD3+ and CD14+ matched populations for research immunological studies.

BACKGROUND: In previous studies with peripheral blood cells, platelet factors were found to be associated with severe allergic phenotypes. A reliable method yielding highly concentrated and pure platelet samples is usually not available for immunological studies. Plateletpheresis is widely used in the clinics for donation purposes. In this study, we designed a protocol based on plateletpheresis to obtain Platelet-Rich Plasma (PRP), Platelet-Poor Plasma (PPP) as well as CD3+ and CD14+ cells matched samples from a waste plateletpheresis product for immunological studies. METHODS: Twenty-seven subjects were voluntarily subjected to plateletpheresis. PRP, PPP and blood cell concentrate contained in a leukocyte reduction system chamber (LRSC) were obtained in this process. CD3+ and CD14+ cells were isolated from the LRSC by density-gradient centrifugation and positive magnetic bead isolation. RNA was isolated from PRP, CD3+ and CD14+ cell samples and used for transcriptomic studies by Affymetrix. PRP and PPP samples were used for platelet protein quantification by multiplex assays. RESULTS: A reliable high yield method to obtain matched samples of PRP, PPP, CD3+ and CD14+ from a single donor for RNA and protein analyses has been designed. The RNA quality indicators (RQI) routinely used for other cell types were not suitable for platelet RNA characterization. Despite this, the platelet RNA was valid for transcriptomic studies by Affymetrix, as platelet transcripts obtained in our previous studies were confirmed in PRP samples. Platelet samples were enriched in platelet factors as determined in protein multiplex analysis. CONCLUSIONS: We have developed a method that yields not only high content and pure platelet samples from a single donor but also CD3+ and CD14+ matched samples that can be used for RNA and protein analyses in immunological studies.

Time from apheresis platelet donation to cold storage: Evaluation of platelet quality and bacterial growth.

BACKGROUND: Cold storage reduces posttransfusion survival of platelets; however, it can improve platelet activation, lower risk of bacterial contamination, and extend shelf-life compared to room temperature (RT) storage. To facilitate large-scale availability, manufacturing process optimization is needed, including understanding the impact of variables on platelet potency and safety. Short time requirements from collection to storage is challenging for large blood centers to complete resuspension and qualify platelets for production. This study evaluated the impact of time from platelet component collection to cold storage on in vitro properties and bacterial growth. STUDY DESIGN AND METHODS: Double-apheresis platelet components were collected from healthy donors, suspended in 65% PAS-III/35% plasma, and split into 2 equal units. One unit was placed into cold storage within 2 h and the other unit after 8 h. Eight matched pairs were evaluated for 12 in vitro parameters. Twenty-four matched pairs were evaluated with 8 bacterial strains tested in triplicate. Samples were tested throughout 21 days of storage. RESULTS: In vitro properties were not different between 2 and 8 h units, and trends throughout storage were similar between arms. Time to cold storage did not significantly impact bacterial growth, with <1 log10 difference at all timepoints between units. DISCUSSION: Our studies showed that extending time to cold storage from 2 to 8 h from collection did not significantly increase the bacterial growth, and the platelet component quality and function is maintained. The ability to extend the time required from collection to storage will improve blood center logistics to feasibly produce CSPs.

Evaluation of amotosalen and UVA pathogen-reduced apheresis platelets after 7-day storage.

BACKGROUND: Amotosalen/UVA pathogen-reduced platelet components (PRPCs) with storage up to 7 days are standard of care in France, Switzerland, and Austria. PRPCs provide effective hemostasis with reduced risk of transfusion-transmitted infections and transfusion-associated graft versus host disease, reduced wastage and improved availability compared with 5-day-stored PCs. This study evaluated the potency of 7-day PRPCs by in vitro characterization and in vivo pharmacokinetic analysis of autologous PCs. STUDY DESIGN AND METHODS: The in vitro characteristics of 7-day-stored apheresis PRPCs suspended in 100% plasma or 65% platelet additive solution (PAS-3)/35% plasma, thrombin generation, and in vivo radiolabeled post-transfusion recovery and survival of 7-day-stored PRPCs suspended in 100% plasma were compared with either 7-day-stored or fresh autologous conventional platelets. RESULTS: PRPCs after 7 days of storage maintained pH, platelet dose, in vitro physiologic characteristics, and thrombin generation when compared to conventional 7-day PCs. In vivo, the mean post-transfusion survival was 151.4 ± 20.1 h for 7-day PRPCs in 100% plasma (Test) versus 209.6 ± 13.9 h for the fresh autologous platelets (Control), (T-ΔC: 72.3 ± 8.8%: 95% confidence interval [CI]: 68.5, 76.1) and mean 24-h post-transfusion recovery 37.6 ± 8.4% for Test versus 56.8 ± 9.2% for Control (T-ΔC: 66.2 ± 11.2%; 95% CI: 61.3, 71.1). DISCUSSION: PRPCs collected in both 100% plasma as well as 65% PAS-3/35% plasma and stored for 7 days retained in vitro physiologic characteristics. PRPCs stored in 100% plasma for 7 days retained in vivo survival. Lower in vivo post-radiolabeled autologous platelet recovery is consistent with reported reduced count increments for allogenic transfusion.

Evaluating apheresis platelets at reduced dose as a contingency measure for extreme shortages.

BACKGROUND: The COVID19 pandemic highlights the need for contingency planning in the event of blood shortages. To increase platelet supply, we assessed the operational impact and effect on platelet quality of splitting units prior to storage. STUDY DESIGN AND METHODS: Using production figures, we modeled the impact on unit numbers, platelet counts, and volumes of splitting only apheresis double donations into three units (yielding ⅔ doses), or all standard dose units in half. To assess quality, eight pools of three ABO/Rh-matched apheresis (Trima Accel) double donations in plasma were split to ⅔ and ½ volumes in both Terumo and Fresenius storage bags. These were irradiated and subject to maximal permitted periods of nonagitation (3 × 8 h) before comparing platelet quality markers (including pH, CD62P expression) to Day 9 of storage. RESULTS: Splitting all double donations into three predicted inventory expansion of 23% overall whereas halving all standard dose units clearly doubles stock. In our study, ⅔ and ½ doses contained 153 ± 15 × 109 (~138 ml) and 113 ± 11 × 109 (~102 ml) platelets respectively. Following storage, higher pH was observed in ⅔ than in ½ doses and in Terumo compared to Fresenius bags. The higher pH was reflected in better quality markers, including lower CD62P expression. Despite the differences, on Day 8 (of pH monitoring at expiry) all ⅔ doses and most ½ doses were ≥pH 6.4. CONCLUSION: A strategy to split apheresis platelets in plasma to lower doses is feasible, maintains acceptable platelet quality, and should be considered by blood services in response to extreme shortages.