Erythrocytes, or red blood cells, are the functional component of blood responsible for the transportation of gases and nutrients throughout the body. Erythrocytes are commonly analyzed in whole blood samples to assess their properties and health status. Human red blood cells exhibit unique molecular and biochemical features that distinguish them from other cell types.

They have a biconcave disc shape and lack a nucleus, which allows for efficient gas exchange. Erythrocyte membrane proteins, such as those found in diverse species, are fundamental to their function.

They are produced in the bone marrow through a process called erythropoiesis. Erythroid cells act as precursors to mature erythrocytes during this developmental process. The erythrocyte membrane contains a variety of proteins, including Band 3 and Glycophorin-A, which play an important role in maintaining erythrocyte integrity and function. Some of these proteins function as adhesion molecules, facilitating cell-to-cell interactions and immune responses.

Structure and function

The erythrocyte membrane is a complex structure composed of a phospholipid bilayer interspersed with various proteins, such as glycophorin A and band 3, which provide both flexibility and mechanical stability. These membrane proteins are essential for maintaining the distinctive biconcave disk shape of normal human erythrocytes, maximizing their surface area for gas exchange. Adhesion molecules, including CD36, are present on the erythrocyte membrane and facilitate interactions with endothelial cells and other red blood cells, supporting smooth blood flow and tissue oxygenation. The structural integrity and specialized features of the erythrocyte membrane are vital for the proper function of human erythrocytes in delivering oxygen to tissues throughout the body.

Clinical applications

Red blood cells are central to many clinical practices, most notably in blood transfusions and the diagnosis of anemia and other red blood cell disorders. In blood banks, stored red blood cells are maintained under carefully controlled conditions to preserve their function and viability. However, during storage, RBCs can undergo changes such as phosphatidylserine exposure, which may impact their lifespan and effectiveness after transfusion. Laboratory medicine plays a key role in monitoring the quality of stored RBCs, ensuring that blood samples used for transfusion are safe and effective for patients. Accurate diagnosis and management of RBC-related disorders rely on advanced laboratory techniques and a thorough understanding of red blood cell biology.

Limitations and challenges

Despite their vital role, the use of red blood cells in clinical settings presents several challenges. The storage time of RBCs is limited, and prolonged storage can increase the risk of complications, such as hemolytic anemia, following transfusion. Diagnosing red blood cell disorders often requires specialized laboratory tests and expertise, as symptoms can be subtle or overlap with other conditions. Ongoing research is essential to improve our understanding of RBC function, storage, and disease, and to develop new therapies for red blood cell disorders. Biomarkers like CD36 and glycophorin A are valuable tools for identifying and monitoring RBCs. However, further studies are needed to fully elucidate their roles in health and disease and enhance patient outcomes.

CD36

CD36 is a widely recognized erythrocyte surface marker involved in lipid transport and cellular adhesion. Expressed on red blood cells, CD36 plays a role in fatty acid uptake and has been linked to metabolic and inflammatory pathways. Its presence on erythrocytes supports studies in hematology, immunology and cardiovascular research. CD36-positive microparticles derived from erythrocytes are increasingly studied as biomarkers in conditions such as type 2 diabetes and atherosclerosis. Understanding CD36 expression on erythrocytes contributes to broader insights into blood-based diagnostics and cellular communication.

Figure 1. Immunocytochemistry/ Immunofluorescence - Anti-CD36 antibody [EPR22509-40] (ab252922).

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CD235a

CD235a, also known as glycophorin A, is a widely used erythrocyte marker in hematology and cell biology. Expressed on the surface of red blood cells, CD235a supports the identification and isolation of erythroid cells in flow cytometry and immunophenotyping. Its role in erythropoiesis research includes tracking maturation stages and studying membrane protein interactions. CD235a is also used to assess red blood cell purity in extracellular vesicle studies. Understanding CD235a expression enhances insights into erythroid lineage development and blood-based diagnostic applications.

Figure 2. Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections) - Anti-Glycophorin A antibody [EPR8200] (ab129024).

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References

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2. Rodriguez-Perales, S. Truncated RUNX1 protein generated by a novel t(1;21)(p32;q22) chromosomal translocation impairs the proliferation and differentiation of human hematopoietic progenitors.  Oncogene  35, 1–10 (2015).
3. Pepino, M. Y., Kuda, O., Samovski, D. & Abumrad, N. A. Structure–function of CD36 and importance of fatty acid signal transduction in fat metabolism.  Annu. Rev. Nutr.  34, 281–303 (2014).
4. Mao, B.  et al.  Early development of definitive erythroblasts from human pluripotent stem cells defined by expression of glycophorin A/CD235a, CD34, and CD36.  Stem Cell Rep.  7, 869–883 (2016).
5. Kuhn, V.  et al.  Red blood cell function and dysfunction: redox regulation, nitric oxide metabolism, anemia.  Antioxid. Redox Signal.  26, 718–742 (2017).