Photooxidant injury to glucose-6-phosphate dehydrogenase-deficient erythrocytes with bilirubin as the sensitizer--an in vitro study.

To evaluate the hypothesis that glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes are more prone to photooxidant injury with bilirubin as the sensitizer, we compared the malonyl dialdehyde (MDA) levels and haematocrit values in 11 G6PD-deficient samples with a bilirubin: albumin molar ratio of 1:2 (10 mg% bilirubin, 2.5 g % albumin) photoexposed at 6 microW cm-2 nm-2 (420-460 nm), with 11 of control samples. Twelve hours after photoexposure the incremental changes in MDA levels (OD units) were higher in G6PD-deficient samples [mean (SE) = 0.230 (0.171) vs 0.075 (0.043), p < 0.01]. Antioxidant drugs may have a protective role while G6PD-deficient neonates undergo phototherapy.