BACKGROUND
Anti‐CD47 (Hu5F9‐G4) is a human monoclonal immunoglobulin G (IgG)4 antibody that is in clinical trials to treat hematologic or solid malignancies. CD47, a glycoprotein expressed on all cells, binds to signal‐regulatory protein α on macrophages and regulates phagocytosis. Blocking CD47 is thought to enhance phagocytosis and promote antitumor responses. Here, we evaluate drug interference in pretransfusion testing, determine mitigation strategies, and compare interference with anti‐CD38 (Daratumumab).
STUDY DESIGN AND METHODS
Samples from four patients were tested by standard methods. Anti‐IgG (Immucor monoclonal Gamma‐clone and Ortho BioClone) were used, and dithiothreitol and enzyme‐treated RBCs were tested. Allo‐adsorption was performed with papain treated RBCs, pooled platelets, or with commercial human platelet concentrate. Platelet antibody testing was performed according to manufacturer's instructions.
RESULTS
All plasma samples reacted 3+ to 4+ in all phases with all red blood cells (RBCs) by all methods including immediate spin. Stronger reactivity was observed with D– RBCs with titers as high as 16,384 at indirect antiglobulin testing. Reactivity at indirect antiglobulin testing using Gamma‐clone anti‐IgG (which does not detect IgG4) was only weakly positive and confirmed to be carryover agglutination. Plasma reacted with dithiothreitol, trypsin, papain, α‐chymotrypsin, or warm autoantibody removal medium (W.A.R.M., Immucor) treated RBCs. Direct antiglobulin testing and autocontrol were negative or weak with 3+ reactive eluates. Reactivity was removed by multiple alloadsorptions with papain‐treated cells or pooled platelets. Polyethylene glycol adsorption was invalid due to precipitation of antibody.
CONCLUSION
Anti‐CD47 (Hu5F9‐G4) interferes with all phases of pretransfusion testing, including ABO reverse typing. To remove interference requires multiple RBC alloadsorptions and/or the use of monoclonal Gamma‐clone anti‐IgG in the indirect antiglobulin testing.
Background and objectives:
The International Society of Blood Transfusion (ISBT) Working Party
for Red Cell Immunogenetics and Blood Group Terminology meets in association
with the ISBT congress and has met three times since the last report: at the
international meetings held in Dubai, United Arab Emirates, September 2016
and Toronto, Canada, June 2018; and at a regional congress in Copenhagen,
Denmark, June 2017 for an interim session.
Methods:
As in previous meetings, matters pertaining to blood group antigen
nomenclature and classification were discussed. New blood group antigens
were approved and named according to the serologic and molecular evidence
presented.
Results and conclusions:
Fifteen new blood group antigens were added to eight blood group
systems. One antigen was made obsolete based on additional data.
Consequently, the current total of blood group antigens recognised by the
ISBT is 360, of which 322 are clustered within 36 blood groups systems. The
remaining 38 antigens are currently unassigned to a known system. Clinically
significant blood group antigens continue to be discovered, through
serology/sequencing and/or recombinant or genomic technologies.
The International Society of Blood Transfusion Working Party on red cell immuno-genetics and blood group terminology convened during the International congress in Cancun, July 2012. This report details the newly identified antigens in existing blood group systems and presents three new blood group systems.
BACKGROUND-The partial D phenotype DIIIa was originally reported to be associated with 455A>C in Exon 3, 602C>G in Exon 4, and 667T>G in Exon 5. Other alleles with these changes were subsequently identified and designated DIII Types 5, 6, and 7, as they had additional alterations. The observation that DNA samples associated with the DIIIa phenotype had more changes than those originally reported motivated us to reanalyze the DIIIa probands (BP and DJ) from the original study. We also studied additional DIIIa samples to clarify the RHD background and establish the associated RHCE.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.