Quantitative assessment of red blood cell surface molecules in hereditary spherocytosis.

Aim: Hereditary spherocytosis (HS) refers to a heterogeneous disorder varying in genotypic and phenotypic features manifested by the production of spherocytes. The diseased cells can be eliminated from the circulatory system either by macrophages in the spleen in the extravascular pathway or the intravascular pathway via the complement cascade. This study aimed to investigate the status of red blood cell (RBC) surface molecules CD55 (decay accelerating factor), CD35 (complement receptor type 1-CR1), CD59 (MACIF), CD47 (marker of self) and CD71 (transferrin receptor) from individuals diagnosed with HS.

Methods: This study aims to quantitatively assess RBC surface molecules (CD35, CD55, CD59, CD47 and CD71) on peripheral RBCs from 42 HS patients and 30 healthy controls, carried out by flow cytometry using monoclonal antibodies.

Results: Our findings show that HS patients had a significant 58% decrease in anti-CD35 binding compared with healthy controls. This is the first study to demonstrate the presence of erythrocytes with reduced CD35 levels in HS patients. Compared with the control group, HS patients had comparable levels of CD59 and CD47, but their CD55 levels were significantly reduced, with a 30% decrease in anti-CD55 binding. The expression level of CD71 was higher in HS patients (3.33%) compared with healthy controls in our study.

Conclusion: The diminished levels of CD35 and CD55 in HS patients may influence RBC clearance, possibly through mechanisms that remain fully understood and require further investigation, including their potential role in haemolytic crises. Further research employing molecular techniques is required to clarify their exact role in HS.