The Course of Experimentally Induced Hemolytic Anemia in a Primaquine-sensitive Caucasian. a Case Study.

T HE SELF-LIMITED NATURE of drug-induced hemolytic crises has been effectively demonstrated by Dern and associates1 in American Negroes, and is believed to be a peculiar feature of primaquine sensitivity. It is well known that gbucose-6-phosphate dehydrogenase-(G-6-PD ) deficient states effect also the Caucasian racial group and particularly the Sardinians among whom 15 per cent are affected.2 Drug sensitive Caucasian males show i considerably lower erythrocyte G-6-PD activity as compared with the enzymatic activity of the red blood cells of sensitive Negro males. In fact in mutant Sardinian males red blood cell G-6-PD activity is 5.2 per cent of the activity of normal ervthrocytes2 whereas the red blood cells of mutant Negro males have 16.7 per cent of the normal G-6-PD activity.3 Furthermore Bonsignore and co-workers,4 after hemolytic crises in favism, and ourselves,5 after experimentally induced hemobytic crises in primaquine sensitive Sardinians, could find no increase in G-6-PD activity in the red blood cells during the reticulocytosis of the recovery phase. This is in contrast with the observations of Marks and Gross3 in primaquine sensitive Negroes. In mutant Negroes the self-limited course of the drug-induced hemolytic crisis is linked to a relative insensitivity to the drug of the younger red cells which have higher levels of G-6-PD activity. It seems therefore predictable that in mutant Caucasian males, whose younger red cells are almost completely devoid of G-6-PD activity, the course of the hemolytic crisis may have a somewhat different pattern. To elucidate this problem we have studied the effects of repeated administrations of primaquine in a mutant Sardinian male. The drug sensitivity of the patient’s erythrocytes, collected both before and after hemolytic crises, was also tested by transfusing the labeled red blood cells into normal recipiemits.