Key PointsQuestionWhat is the effect of convalescent plasma therapy added to standard treatment, compared with standard treatment alone, on clinical outcomes in patients with severe or life-threatening coronavirus disease 2019 (COVID-19)?FindingIn this randomized clinical trial that included 103 patients and was terminated early, the hazard ratio for time to clinical improvement within 28 days in the convalescent plasma group vs the standard treatment group was 1.40 and was not statistically significant.MeaningAmong patients with severe or life-threatening COVID-19, convalescent plasma therapy added to standard treatment did not significantly improve the time to clinical improvement within 28 days, although the trial was terminated early and may have been underpowered to detect a clinically important difference.

The ABO blood group system is the most clinically important in blood transfusion. The decreased expression levels of A or B antigens of the ABO subtype often present difficulties in blood typing and cross-matching for clinical transfusion. B 3 is the most common B subtype, which has a frequency of approximately 1 in 900 in the Chinese population. The underlying mechanisms of the B 3 phenotype were diversified. Several mutations in the exons, splicing site, and mutations in the promoter have been reported for B 3.1,2 Recently, a regulatory element was identified in the first intron of the ABO gene with a functional GATA-1 erythroid transcription factor binding site. 3 Studies have shown that mutations in the erythroid cell-specific regulatory element (15.8 kb) can cause variant ABO phenotypes. 2,4 Here, we report a novel single-nucleotide substitution within the GATA motif (C>T substitution at Position c.28 1 5885) in the 15.8-kb site on the B allele in one individual with the B 3 phenotype. METHODS AND RESULTSA blood sample from a 44-year-old Chinese Han male patient who was admitted to our hospital for treatment of arrhythmia was referred to our laboratory because the B antigen of red blood cells (RBCs) demonstrated mixedfield agglutination when tested with routine ABO blood group typing. He had no history of blood transfusion. The blood sample was collected after informed consent was obtained, and genomic DNA was extracted by a commercial kit according to the manufacturer's instructions (TIANamp blood DNA kit, Tiangen Biotech Co.). ABO blood group typing was routinely determined by a gel test kit (Ortho ABO-Rh/reverse grouping cassette, Ortho-Clinical Diagnostics). The forward typing was further confirmed by a manual tube test using monoclonal anti-A, anti-B, anti-AB, and anti-H (Blood Grouping Reagent, Shanghai Hemo-Pharmaceutical & Biological, Co., Ltd) according to the standard protocols. Reverse typing was also performed with a tube test using A 1 , B, and O RBCs.The upstream CBF/NF-Y enhancer region, promoter, all seven exons and adjacent introns of the ABO gene were amplified and sequenced according to previously published methods. 5 The method of amplification for the ABO 15.8-kb site is shown in Appendix S1 (available as supporting information in the online version of this paper).On forward typing by the gel column method, the RBCs of the patient had no reaction with anti-A and mixed-field agglutination (21) with anti-B and anti-AB reagents, but there was a strong reaction with anti-H sera (41). On reverse typing, the serum of the patient was agglutinated by standard A 1 RBCs (21), and it was not agglutinated by standard B and O RBCs.Direct sequencing demonstrated the B101/O02 genotype in this proband. However, one point mutation in the element was identified with the presence of a novel single-nucleotide substitution within the GATA motif From the

Sonoclot analyzer has been widely used in many countries. But the reference intervals provided by the manufacturer were derived from only 45 participants, and there was no cut-off value for transfusion for Sonoclot analysis. This study aimed to establish reference intervals and transfusion criterion for Sonoclot analysis. Volunteers were recruited from healthy Chinese adults and patients undergoing cardiac surgery. Blood samples were withdrawn from forearm vein and measured for activated clotting time (ACT), clot rate (CR), platelet function (PF), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), and platelet count (PLT). The reference intervals were determined by the nonparametric method. Cut-off values were determined by the receiver operating characteristics curve. A total of 135 healthy volunteers and 281 patients were enrolled. The 95% reference intervals were 96-195 s, 22-51 signal U/min, >1.6 for ACT, CR, PF respectively. In the 281 patients, the results of APTT, FIB, PLT, ACT, CR, and PF ranged from 20.5-300.0 s, 0.28-4.11 g/L, (19.0-387.3)×109/L, 80-514 s, 2.9-74 signal U/min, and 0.1-5.1 respectively. The cut-off values for transfusion were >208, ≤14, and ≤1.3 for ACT, CR, PF respectively. The cut-off values of Sonoclot analysis were within the manufacturer's reference intervals, while they were outside the reference intervals established in this study. The results suggested that the manufacturer's reference intervals were not suitable for Chinese. The reference intervals and cut-off values established in this study will be helpful to Chinese patients.