Association of Micro RNA-155 with Alloimmunization in Transfusion-Dependent Thalassemia Patients.

Thalassemia is one of the most prevalent genetic disorders. Blood transfusion, as the main treatment, harbors diverse side effects, including alloimmunization to RBC antigens, exacerbating hemolysis, and blood requirements. The role of miR155, as a regulator of the immune system, was investigated to divulge its role in the production of alloantibodies in thalassemia patients. The antibody screening technique was used to identify TDT patients with alloimmunization against erythrocyte antigens. PBMC were isolated from selected TDT patients and matched controls using the Ficoll-Paque method, and then miRNA was extracted from cells by the TRIzol reagent. Finally, the relative expression of miR155 was measured using the stem-loop RT-PCR technique. One hundred fifty-eight patients with TDT were screened for the presence of alloantibodies, of whom 14 patients were identified to develop alloimmunization against RBC antigens. There was no statistically significant difference between TDT patients with or without alloantibodies (15 age and sex matched non-immunized patients) in terms of the frequencies of splenectomy, vaccination against hepatitis B, blood types, RHD positivity, and various complications. The expression of miR155 was significantly higher in patients with alloantibodies (mean fold change: 4.74 ± 2.76) compared to non-immunized TDT patients (mean fold change: 1.8 ± 0.68,  = 0.002). Our findings indicated that miR155 overexpression can be involved in modulating immune responses and triggering the production of alloantibodies in TDT patients. More studies are required in this field to further elucidate the role of miR155 in alloimmunization of these patients and other conditions associated with this problem.