Lymphocyte changes in favism: in vitro evidence of a modifying effect of bilirubin and hemoglobin on T-lymphocyte receptors.

Lymphocyte subpopulations were studied in 13 Sicilian glucose-6-phosphate dehydrogenase (G6PD)-deficient children during and after the hemolytic crisis due to fava bean ingestion. A statistically significant reduction of sheep-red-cell (SRC)-rosetting lymphocytes occurred in all patients during the hemolytic crisis, whereas B lymphocytes were not affected. In order to establish the possible relationship between serum changes occurring during hemolysis and reduction of SRC-rosetting lymphocytes, the effect in vitro of varying concentrations of bilirubin and hemoglobin on the rosette formation capacity of lymphocytes was studied. Both substances produced a statistically significant reduction of SRC-rosetting lymphocytes both in normal and deficient subjects. This effect showed a direct relationship with the concentrations of bilirubin and hemoglobin used and was more pronounced on lymphocytes from G6PD-deficient children. These data suggested that the reduction of SRC-rosetting lymphocytes observed during acute hemolysis of favism can be related to a modifying effect of bilirubin and hemoglobin.