Assessment of Complement Regulatory Proteins CD55 and CD59 on Erythrocytes in Beta-Thalassemia Major Patients.

This study intended to measure the expression of complement regulatory proteins CD55 and CD59 on RBCs membrane in patients with ß-thalassemia (ß- thal) major in addition to investigate if splenectomy affects their expression pattern. This was a case-control study, participants were allocated in three groups. The study group 1 consisted of ß-thal patients who underwent splenectomy. The study group 2 consisted of ß-thal patients without splenectomy. Group 3 consisted of apparently healthy volunteers as a control group. A significant decrease in CD55 expression in patients' group 1 (46.35±14.61) and group 2 (56.90±9.28) in comparison with group 3 (86.20±9.62) was observed. The percentage of CD55 expression was significantly lower in group 1 patients than group 2 (P=0.01). However, there was no difference in the percentage of CD59 marker expression between any of the patient's groups and the control group. In conclusion, CD55 under-expression on RBCs of ß- thal patients may be considered one of the factors that cause hemolysis in those patients and this complement mediated hemolysis may be one of the underlying causes of organ damage. Additional deficiency of this receptor occurs with splenectomy.