RESUMO
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.
RESUMO
BACKGROUND: The COVID-19 pandemic is expected to cause significant morbidity and mortality. The development of an effective vaccine will take several months to become available, and its affordability is unpredictable. Transfusion of convalescent plasma (CP) may provide passive immunity. Based on initial data from China, a group of hematologists, infectious disease specialists, and intensivists drafted this protocol in March 2020. OBJECTIVE: The aim of this study is to test the feasibility, safety, and efficacy of CP in treating patients with COVID-19 across Saudi Arabia. METHODS: Eligible patients with COVID-19 will be recruited for CP infusion according to the inclusion criteria. As COVID-19 has proven to be a moving target as far as its management is concerned, we will use current definitions according to the Ministry of Health (MOH) guidelines for diagnosis, treatment, and recovery. All CP recipients will receive supportive management including all available recommended therapies according to the available MOH guidelines. Eligible CP donors will be patients with COVID-19 who have fully recovered from their disease according to MOH recovery criteria as detailed in the inclusion criteria. CP donors have to qualify as blood donors according to MOH regulations except for the history of COVID-19 in the recent past. We will also test the CP donors for the presence of SARS-CoV-2 antibodies by a rapid test, and aliquots will be archived for future antibody titration. Due to the perceived benefit of CP, randomization was not considered. However, we will compare the outcome of the cohort treated with CP with those who did not receive CP due to a lack of consent or lack of availability. In this national collaborative study, there is a likelihood of not finding exactly matched control group patients. Hence, we plan to perform a propensity score matching of the CP recipients with the comparator group patients for the major characteristics. We plan to collect demographic, clinical, and laboratory characteristics of both groups and compare the outcomes. A total sample size of 575 patients, 115 CP recipients and 460 matched controls (1:4 ratio), will be sufficient to detect a clinically important hospital stay and 30-day mortality difference between the two groups with 80% power and a 5% level of significance. RESULTS: At present, patient recruitment is still ongoing, and the interim analysis of the first 40 patients will be shared soon. CONCLUSIONS: In this paper, we present a protocol for a national collaborative multicenter phase II study in Saudi Arabia for assessing the feasibility, safety, and potential efficacy of CP in treating patients with severe COVID-19. We plan to publish an interim report of the first 40 CP recipients and their matched comparators soon. TRIAL REGISTRATION: ClinicalTrials.gov NCT04347681; https://clinicaltrials.gov/ct2/show/NCT04347681. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/23543.
