Erythrocyte membrane proteins reactive with IgG (warm-reacting) anti- red blood cell autoantibodies: II. Antibodies coprecipitating band 3 and glycophorin A

Abstract

In our initial immunochemical study of the red blood cell (RBC) membrane proteins targeted in 20 cases of warm-antibody autoimmune hemolytic anemia (AHA), RBC eluates of 6 patients mediated immunoprecipitation (IP) of both band 3 and glycophorin A (GPA). This dual IP pattern had previously been observed with murine monoclonal antibodies (MoAbs) against the high frequency blood group antigen, Wrb (Wright), suggesting that the Wrb epitope may depend on a band 3-GPA interaction. Earlier, anti-Wrb had been identified serologically as a prominent non-Rh specificity of AHA autoantibodies. In the present study, 6 autoantibody eluates immunoprecipitating band 3 and GPA from common Wr(b+) RBCs were retested, in parallel with murine anti-Wrb MoAbs, against very rare Wr(a+b-)En(a+)RBCs. One patient's autoantibodies were unreactive with the Wr(b-) RBCs by either IP or indirect antiglobulin test (IAT) and were judged to have “pure” anti- Wrb specificity. Two other patients' autoantibodies displayed both IP and serologic evidence for anti-Wrb as a major component in combination with one or more additional specificities. However, among 3 other patients whose autoantibodies coprecipitated band 3 and GPA, there was no reduction in IP or IAT reactivity with Wr(b-) RBCs in 2 and only slight reduction in the third. We conclude (1) that human anti-Wrb autoantibodies, like their murine monoclonal counterparts, coprecipitate band 3 and GPA from human RBCs; but (2) that not all antibodies with this IP behavior have anti-Wrb serologic specificity, as defined by this donor's Wr(b-) RBCs. The possibility of an additional (non-Wrb) RBC epitope dependent on a band 3-GPA interaction is raised.

Survival differences and associated molecular signatures of DNMT3A-mutant acute myeloid leukemia patients

“…In addition, we also identified genes that are expressed in different blood components. This included three genes downregulated in the short-lived subgroup - SLC4A1 , GYPA and RPS19 - that have previously been associated with anemia 72 – 74 . Notably, SLC4A1 and its co-factor GYPA play a major role in oxygen and carbon dioxide exchange in erythrocytes 75 , 76 and their downregulation in the short-lived subgroup could be associated with less differentiated leukemic cells.…”

Potentially antigenic RBC membrane proteins in dogs with primary immune‐mediated hemolytic anemia

“…These might include canine serum components such as complement C3 fragments. Activation of serum complement can result in binding of C3d (molecular weight ~35 kDa) to IgG . Consequently, C3d could have been present in the “purified IgG” preparation used to immunize the sheep and in the “purified canine IgG” sourced from VMRD Inc.…”

Detection of hereditary pyropoikilocytosis by the eosin-5-maleimide (EMA)-binding test is attributable to a marked reduction in EMA-reactive transmembrane proteins

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