HLA and red blood cell antigen genotyping in SARS-CoV-2 convalescent plasma donors.

More data is required regarding the association between HLA allele and red blood cell (RBC) antigen expression in regard to SARS-CoV-2 infection and COVID-19 susceptibility. ABO, RhD, 37 other RBC antigens and HLA-A, B, C, DRB1, DQB1 and DPB1 were determined using high throughput platforms in 90 Caucasian convalescent plasma donors. The AB group was significantly increased (1.

Validation of a rapid potency assay for cord blood stem cells using phospho flow cytometry: The IL-3-pSTAT5 assay.

Introduction: Public cord blood banks (CBBs) are required to measure cord blood units (CBUs) potency before their release, allowing for the identification of units that may be unsuitable for haematopoietic transplantation. We have developed a rapid flow cytometry assay based on the measurement of STAT-5 phosphorylation of CD34+ stem cells in response to IL-3 stimulation.

Method: To adapt the assay from a research setting to its implementation within our CBB regulated operations, we proceded with a full method validation and a correlation comparison of the IL-3-pSTAT5 assay results with the colony-forming unit assay (CFU) results.

Multicenter evaluation of the IL-3-pSTAT5 assay to assess the potency of cryopreserved stem cells from cord blood units: The BEST Collaborative study.

Background: The IL-3-pSTAT5 assay, a new, rapid, and standardized flow-cytometry-based assay may compensate for several limitations of the colony-forming unit (CFU) assay typically used for stem cell potency assessments of cord blood units (CBU). We performed an inter-laboratory evaluation of the performance of this new assay.

Study Design And Methods: This Biomedical Excellence for Safer Transfusion (BEST) Collaborative multicenter, international study included 15 participants from public cord blood banks (CBBs), CBB-supporting research laboratories, and stem cell laboratories.

Rapid potency assessment of autologous peripheral blood stem cells by intracellular flow cytometry: the PBSC-IL-3-pSTAT5 assay.

Background Aims: The current gold standard for stem cell product potency assessment, the colony-forming unit (CFU) assay, delivers results that are difficult to standardize and requires a substantial amount of time (up to 14 days) for cellular growth. Recently, the authors developed a rapid (<24 h) flow cytometry assay based on the measurement of intracellular phosphorylated STAT5 (pSTAT5) in CD34+ cord blood stem and progenitor cells in response to IL-3 stimulation. The present work presents a novel adaptation of the protocol for use with autologous peripheral blood stem cells (PBSCs) and a performance comparison with the CFU assay.

Weak D type 42: Antigen density and risk of alloimmunization in the province of Québec.

Background And Objectives: A high proportion of suspected weak D patients referred to Héma-Québec were genotyped as weak D type 42 (368/2105, 17.5%). These patients are currently considered D with regard to RhD immunoprophylaxis in pregnancy and transfusion.

Standardization of a flow cytometry SARS-CoV-2 serologic test.

Unlabelled: The SARS-CoV-2 virus is the causing agent of the coronavirus disease 2019 (COVID-19) pandemic responsible for millions of deaths worldwide. The development of the humoral response to the virus has been the subject of intensive research. A flow cytometry-based assay using native full-length SARS-CoV-2 Spike protein expressed in 293 T cells was recently proposed as a complementary seropositivity assay.

Preparation and growth factor characterization of cord blood-derived plasma, serum, growth factor-rich plasma and induced serum.

Background: In recent years, there has been a significant decline in the demand for cord blood units (CBUs). This trend has led to cord blood banks (CBBs) exploring complementary uses of CBUs in order to exploit the full potential of this unique, valuable, and readily available product. The aim of this study was to establish standardized protocols for the preparation of four cord blood (CB) derivatives: plasma (CB-P), serum (CB-S), induced-serum (CB-IS) and growth factor-rich plasma (GFRP); to measure their respective growth-factor content and their potential as cell culture supplements, and finally, to identify the characteristics of each derivative beyond their growth-factor composition, in the context of optimizing CBBs resources.

High prevalence of weak D type 42 in a large-scale RHD genotyping program in the province of Quebec (Canada).

Background: The determination of the RhD phenotype is crucial to avoid alloimmunization, especially in childbearing women. Following the 2015 recommendation from the Work Group on RHD Genotyping, a large-scale RHD genotyping program was implemented in the province of Quebec (Canada) and offered to women ≤45 years old with a serological weak D or discordant results. Since weak D type 42 was previously shown to be prevalent among French Canadians, genotyping for that variant was also performed.

Adapting to supply-and-demand emerging trends for antigen-negative red blood cell units.

Background: A global downtrend in blood usage has been observed by many countries, while the demand for antigen-negative red blood cell (RBC) units used in antigen-matched transfusions keeps increasing. The declining number of units collected exposes blood providers to a rapidly evolving supply challenge.

Methods: This study was conducted retrospectively with use of internal data analysis to weigh Québec's situation regarding global and antigen-negative RBC demand, to measure the effects of community-directed recruitment and blood drives, and to evaluate the benefits of mass-scale RBC genotyping.

Multi-laboratory assay for harmonization of enumeration of viable CD34+ and CD45+ cells in frozen cord blood units.

Background Aims: In 2016, specifications for both pre-cryopreserved and post-thawed cord blood were defined in the sixth edition of NetCord Foundation for the Accreditation of Cellular Therapy (FACT) Standards for Cord Blood Banks. However, for several experts, harmonization regarding flow cytometry analysis performed on post-thawed samples is still a concern. A multicenter study led by Héma-Québec aimed to provide scientific data to support the cord blood accreditation bodies such as NetCord FACT in the revision of standards.

Intravenous immunoglobulin modulates the expansion and cytotoxicity of CD8+ T cells.

Intravenous immunoglobulin (IVIg) is successfully used in the treatment of autoimmune diseases involving self-reactive CD8(+) T cells. However, its direct influence on the cytotoxic response remains unknown. Using an antigen cross-presentation assay and a mouse model of ovalbumin (OVA) immunization, we showed that IVIg decreases the in vitro activation, proliferation and cytokine secretion of OVA-specific CD8(+) T cells (OT-I), as well as the in vivo generation of OVA-specific CD8(+) T cells.

Cationized IVIg as a potential substitute to IVIg for the treatment of experimental immune thrombocytopenia.

In this study, we evaluated the possibility of using cationized IVIg (cIVIg) instead of IVIg as a more effective therapy for the treatment of experimental immune thrombocytopenia in mice. The pharmacokinetics (PK) and biodistribution of cIVIg and IVIg in mice were compared. cIVIg displayed a shorter plasma half-life and an increased organ uptake in both the spleen and liver compared to IVIg, suggesting that cIVIg could be more potent than IVIg to prevent platelet clearance in a mouse model of thrombocytopenia.

IVIg-mediated inhibition of antigen presentation: predominant role of naturally occurring cationic IgG.

The infusion of high doses of intravenous immunoglobulins (IVIg) produce anti-inflammatory effects in a diversity of autoimmune disorders. The need for such high doses suggests that only a small fraction of IgG is responsible for the anti-inflammatory effects. We recently showed that IVIg was internalized in APCs to compete with antigens for loading on MHC II molecules, leading to reduced antigen-specific T cell responses.

Prevention of T cell activation by interference of internalized intravenous immunoglobulin (IVIg) with MHC II-dependent native antigen presentation.

Activation of self-reactive CD4(+) T cells plays a central role in the initiation and maintenance of autoimmune diseases. We recently reported that intravenous immunoglobulin (IVIg) inhibits the MHC II-restricted CD4(+) T cell activation induced by the presentation of immune complexes. Because native antigens can also play a role in the induction of several autoimmune diseases, we determined whether IVIg could also affect CD4(+) T cell activation following presentation of native antigens by APCs.