Drug-induced haemolytic anaemia in dermatitis herpetiformis. The importance of Heinz bodies in its recognition

Screening for glucose-6-phosphate dehydrogenase deficiency prior to dapsone therapy

Dapsone is widely used in dermatological practice. The case of a Greek female patient is reported who had a severe, acute, haemolytic episode shortly after commencing dapsone therapy, despite a normal glucose-6-phosphate dehydrogenase (G6PD) screening test. A subsequent quantitative assay revealed reduced levels of G6PD consistent with the heterozygous state. This illustrates that routine screening tests may fail to detect the decreased levels of (G6PD) which occur in female heterozygotes. Since these patients are at risk of severe dapsone-induced haemolysis, the need for quantitative G6PD assays in females from susceptible racial groups is emphasized.

Heinz-body anemia: "bite cell" variant--a light and electron microscopic study

Light and scanning electron microscopic studies of blood from five patients with drug-induced oxidant hemolysis are presented. None of the patients had a previous history of hemolytic disease and laboratory studies indicated no evidence of either glucose-6-phosphate dehydrogenase (G6PD) deficiency or unstable hemoglobinopathy. Although the red cell deformities in our patients overlapped to some extent with those reported in patients with microangiopathic hemolytic anemia (MAHA) and in patients with G6PD deficiency undergoing oxidant hemolysis, striking differences were also observed. Cell fragments, commonly found in patients with MAHA, and eccentrocytes, frequently found in patients with G6PD deficiency undergoing oxidant hemolysis, were seldom found in blood samples from the five patients in this study. Bite cells were extremely common in our patients. They are rare in patients with either of the above disorders. An awareness of the morphologic abnormalities detailed in this report may help characterize the nature of a hemolytic process so that appropriate therapy can be initiated.

Studies on dapsone induced haemolytic anaemia. I. Methaemoglobin production and G-6-PD activity in correlation with dapsone dosage

The present study was undertaken on the hypothesis that methaemoglobin production and haemolytic anaemia following dapsone administration could be ascribed to an impairment of glucose-6-phosphate dehydrogenase-enzymatic activity. Analysis of the kinetic parameters of the G-6-PD (Vmax and KM) was performed in ten patients, normal with respect to G-6-PD, suffering from various dermatoses. It was concluded that haemolytic anaemia after dapsone therapy is not due to a functional impairment of the enzyme. The close relationship between dapsone dosage, methaemoglobin production and anaemia make reasonable the hypothesis that a toxic dapsone derivative (DDS-NHOH) could be responsible for the methaemoglobin formation and the haemolytic anaemia.

Spectrofluorescent detection of in vivo red cell lipid peroxidation in patients treated with diaminodiphenylsulfone

In the absence of vitamin E deficiency, red cell lipid peroxidation has not been clearly demonstrated in freshly drawn blood obtained from patients with various hemolytic anemias despite indirect evidence that oxidative decomposition of cell membrane unsaturated fatty acids occurs in these particular hemolytic states. Recent studies have indicated that malonaldehyde, a decomposition product of oxidized polyunsaturated fatty acids, is able to covalently cross-link the amino groups of protein or lipid resulting in a fluorescent compound. In the present study we have utilized spectrofluorescent technique to assess whether such fluorescence is present in red cell lipid extracts in association with lipid peroxidation. In vitro red cell lipid peroxidation produced by ultraviolet radiation or the oxidant gas ozone was associated with the development of a fluorescent peak (excitation maximum 360 nm; emission maximum 440 nm) in lipid-containing red cell extracts Similar fluorescence was observed after incubation of red cells with malonaldehyde or with malonaldehyde-containing extracts of peroxidized red cell lipid. Spectrofluorescent evaluation of chloroform: isopropanol extracts obtained from the freshly drawn red cells of six patients receiving the oxidant hemolytic drug diaminodiphenylsulfone also revealed a peak at 440 nm which ranged from 39 to 78 U. In contrast, the levels in samples obtained from 11 hematologically normal subjects were 17-27 fluorescence U. No evidence for an increase in blood levels of free malomaldehyde was observed using the 2-thiobarbituric acid test which is the most commonly performed assay of lipid peroxidation. Serum vitamin E levels were within the normal range. Density separation indicated that the bulk of the fluorescence was present in older red cells. A similar fluorescent peak was also observed in lipid-containing extracts of red cells obtained from rabbits repeatedly injected with phenylhydrazine. The finding of fluorescent spectra consistent with the cross-linking of aminolid by malonaldehyde in the red cells of patients receiving diaminodiphenylsulfone indicates that in vivo red cell lipid peroxidation does occur in the absence of vitamin E deficiency.