Lab Studies

Correlation of RBC inflammatory and metabolomic profiles with RBC hemolysis potential and clinical outcome in transfusion recipients

This protocol will extend the findings from the REDS-III RBC-Omics protocol to include novel markers of RBC units using serial samples from the existing repository.  The measures to be added to the existing hemolysis and genetic data include potential soluble inflammatory mediators (mitochondrial DNA and extracellular vesicles, or EVs) and an assessment of the metabolomic profile of the RBC units.  In Aim 1 these measures will be tested at days 10, 20, and 42 of storage, and they will be correlated with the existing hemolysis and genetic data from the REDS-III study.  In addition, the stability of these novel markers across donations in a given donor will be determined using a subset of 100 samples from the repository with 42 day stored samples from two different donations from the same donor available.  In Aim 2 parameters that are found to be stable in donors across donations will be correlated with clinical outcome in transfused patients, drawing on the REDS-III vein-to-vein database.  This protocol will identify how novel in vitro markers of RBC unit function correlate with each other, and will help generate hypotheses about which parameters might correlate with the potency or efficacy of RBC products.

Blood safety implications and advancing testing for screening donors with HIV infections taking antiretroviral (ART) and pre-exposure prophylaxis (PrEP) therapies

Recent studies of blood donors from several countries including the US have documented that persons with non-disclosed but known HIV infections who are taking antiretroviral therapy (ART) and donors on pre-exposure prophylaxis (PrEP) are increasingly presenting for blood donation despite intake questions that should have precluded eligibility for donation. The objective of this project is to characterize the altered dynamics of viremia and seroconversion and performance of donor screening assays following early ART, during PrEP and after PrEP-breakthrough infections. Panels will be constructed using archived longitudinal plasma samples from early-treated participants in SF, South Africa and Thailand early treatment studies. For PrEP we will construct panels of longitudinal plasma from the iPrEx and Partners PrEP studies, including from participants diagnosed as infected when initiating, while on or shortly after stopping PrEP and from the highest risk participants who were not determined to be infected based on the study diagnostic testing assays/algorithms. Panels will be tested by currently employed blood screening NAT and serology assays and by next-generation HIV molecular and serology assays developed by Roche, Ortho, Abbott, and Grifols. We will further establish whether testing WB (using simple WB processing methods) by donor screening NAT and VL assays/platforms enables detection of HIV infections not detectable by current plasma-based testing algorithms. To further establish the rate of non-disclosed ART and PrEP use in donors, CDC collaborators will perform ART drug testing on donation samples that are Ab+/NAT- or Ab-/NAT+ with low plasma VLs. We will also investigate whether novel, sensitive multiplexed HIV antigen-based assays spanning the proteome can detect low level humoral immune responses not detectable by current available donor screening and diagnostic serological assays, which will lead to insights toward enhancement of those assays. A subset of 500 samples from the early-ART and PrEP panels and from the paired donation/PrEP WB/plasma samples (selected based on HIV RNA/NA detection but negative or borderline reactive serology) will be compiled into panels and tested by novel serological assays.

Evaluation of biotinylated red blood cells

Biotinylated red cells can be used in human clinical research studies to evaluate the recovery and survival of transfused erythrocytes. To our knowledge, no previous studies have evaluated the feasibility of using a remote central lab for RBC biotinylation and analyses services (previous studies have used local facilities). The study aims to optimize and standardize a RBC biotinylation protocol for the evaluation of RBC posttransfusion recovery and survival. Specifically, the study will evaluate the impact of RBC biotinylation procedures at a site (REDS-IV-P Center for Transfusion Laboratory Studies in Denver, CO) that is remote from the site where transfusion occurs (University of Colorado Denver).

Part 1 of this study will address the impact of remote processing on in vitro measurements of BioRBC recovery and survival. If supported by findings from Part 1 of the study, Part 2 will involve the application of the tested and validated biotinylation technique to in vivo studies.