Improvement of mouse beta thalassaemia by hydroxyurea.

The present report provides evidence that hydroxyurea (HU) improves the beta thalassaemic phenotype in mice receiving 200 mg/kg/d for 30 d. The haematocrit rose from 29 +/- 3% at day 0 to 37 +/- 4% at day 30 (P < 0.05), despite myelosuppression and decreased reticulocyte counts. The beta minor/alpha ratio of globin chain synthesis increased from 0.78 at day 0 to 0.97 at day 30 (P < 0.001). Membrane defects improved: the proportion of bound alpha chains decreased, the proportion of spectrin and ankyrin increased and red cell deformability also increased.