Hydroxyurea therapy lowers circulating DNA levels in sickle cell anemia

Hydroxyurea reduces the frequency of acute pain in sickle cell disease (SCD). We sought to determine if hydroxyurea therapy affects cell free DNA (cfDNA) levels in SCD. cfDNA levels fell in all 10 patients studied; before hydroxyurea, mean was 1,879 (95% CI 1,104-3,199) GE/mL; after hydroxyurea, mean was 780 (95% CI, 634-959) GE/mL (P = 0.002). Mean cfDNA level in the 10 HbSS adults prior to starting hydroxyurea was also significantly higher than that in 115 HbSS case controls who had never taken hydroxyurea (1,879 vs 975 GE/mL, P = 0.02). cfDNA levels may be useful in monitoring response to hydroxyurea therapy in SCD.