Frequency of T Regulatory Cells Subpopulations in Hemophilia A Patients with Inhibitors

Hemophilia A is a hemorrhagic disease caused by a quantitative/qualitative deficiency of factor VIII. It is classified as severe, moderate, or mild based on its residual procoagulant activity. Long-term administration of FVIII promotes the development of neutralizing antibodies (inhibitors) in almost 30% of patients with the severe form of the disease. Currently, the role of regulatory T cells in the development of these antibodies is conflicting. Accordingly, the aim of this study was to determine the percentage of regulatory T cells subpopulations by flow cytometry in 10 healthy subjects, 15 patients with severe hemophilia without inhibitors, and 8 with inhibitors. No significant differences in the frequency of regulatory T cells subpopulations were found between hemophilia A patients with inhibitors versus hemophilia A patients without inhibitors or healthy subjects. Our results suggest that the role of the regulatory T cells populations on the development of inhibitors in adult patients with hemophilia A is questionable. However, further analysis of the etiological relevance of these cells requires future research.