Impact of hydroxyurea on lymphocyte subsets in children with sickle cell anemia

A comprehensive study of immune function and immunophenotyping of white blood cells from β‐thalassaemia/HbE patients on hydroxyurea supports the safety of the drug

“…The effect of HU treatment on cells of the lymphoid lineage was elucidated in children with SCD after a year of HU treatment (20 mg/kg/day) which significantly reduced the rate of vaso‐occlusive crisis and acute chest syndrome. In that study, HU treatment restored the levels of CD3 + lymphocytes, CD8 + T cells, Tc2 cells and NK cells into the reference range, without affecting CD4 + T cells, the Th1/Th2 ratio, the Tc1/Tc2 ratio, the CD4 + /CD8 + ratio, and on B cells and NKT cells 19 . In this study, low‐dose HU treatment (10 mg/kg/day) in β‐thalassaemia/HbE patients had no significant effect on the numbers of circulating neutrophils, monocytes, granulocytic‐MDSCs, granulocytic‐MDSCs and lymphocytes, including CD4 + T cells and CD8 + T cells.…”

“…HU is currently used as a cancer chemotherapeutic agent (50-150 mg/kg/day). 18 HU has additionally been re-purposed to be applied in other therapeutic treatment approaches, such as inducing HbF production in SCD (20 mg/kg/day) 19,20 and βthalassaemia (8-20 mg/kg/day) [21][22][23] and as an antiretroviral drug in patients with HIV-1 infection (1000 mg/day). 24 Although HU has long been regarded with concern for mutagenic and potentially carcinogenic effects, new studies have shown that HU is not mutagenic and has minimal carcinogenic risks in SCD.…”