A remarkable augmentation of Hb F and a reduction of Hb A2 were observed in a Sicilian woman during and after a course of treatment for Hodgkin’s disease. An inverse correlation between the proportion of Hb F and Hb A2 was found over an 8-year period, as well as in populations of red blood cells fractionated by density gradient. She exhibited two genetic defects, the Swiss type of heterocellular hereditary persistence of fetal hemoglobin and a β-thalassemia trait, which were confirmed by the study of the hemoglobin synthesis and by a family study. The lasting reactivation of Hb F synthesis is attributable to the interaction of several acquired and inherited facto