Glutathione S-transferase T1-null seems to be associated with graft failure in hematopoietic SCT.

Hematopoietic SCT (HSCT) from HLA-matched donors is sometimes complicated by GVHD or graft rejection, because of mismatched mHA. This study presents data suggesting the involvement of glutathione S-transferase theta-1 (GSTT1), a phase II detoxifying enzyme encoded by GSTT1, in Ab-mediated rejection of HSCT in children with congenital hemoglobinopathies (CHs). Mismatch of GSTT1, which often features a deletion polymorphism variant, can have major consequences in solid organ transplantation outcome. In liver transplantation, it has been shown to lead to de novo hepatitis, whereas in kidney transplantation, chronic allograft rejection has been documented. In this study on 18 children with CH who underwent HSCT, five cases of graft rejection occurred, all in GSTT1-null patients, four of which featured anti-GSTT1 antibodies. The data suggest that when GSTT1-null patients are transplanted with a GSTT1-positive graft, rejection due to an Ab-mediated immune response against GSTT1 displayed on transplanted stem cells may take place. Thus, it seems that detection of anti-GSTT1 antibodies in patients with a GSTT1-null genotype before transplantation may be predictive of graft rejection in the event of a GSTT1-positive donor.

Disorders of oxidised haemoglobin.

Methaemoglobinaemia arises from the production of non-functional haemoglobin containing oxidised Fe(3+) which results in reduced oxygen supply to the tissues and manifests as cyanosis in the patient. It can develop by three distinct mechanisms: genetic mutation resulting in the presence of abnormal haemoglobin, a deficiency of methaemoglobin reductase enzyme and toxin-induced oxidation of haemoglobin. The normal haemoglobin fold forms a pocket to bind the haem and stabilise its complex with molecular oxygen, simultaneously preventing spontaneous oxidation of the Fe(2+) ion chelated by the haem pyrroles and the globin histidines. In the abnormal, M forms of haemoglobin (Hb Ms) amino acid substitution in or near the haem pocket creates a propensity to form methaemoglobin instead of oxyhaemoglobin in the presence of molecular oxygen. Normally, haemoglobin continually oxidises but significant accumulation of methaemoglobin is prevented by the action of a group of methaemoglobin reductase enzymes. In the autosomal recessive form of methaemoglobinaemia there is a deficiency of one of these reductase enzymes thereby allowing accumulation of oxidised Fe(3+) in methaemoglobin. Oxidising drugs and other toxic chemicals may greatly enhance the normal spontaneous rate of methaemoglobin production and if levels exceed 70% of total haemoglobin, vascular collapse occurs resulting in coma and death. Under these conditions, if the source of toxicity can be eliminated methaemoglobin levels will return to normal. Disorders of oxidised haemoglobin are relatively easily diagnosed and in most cases, except for the presence of congenitally defective haemoglobin M, can be treated successfully.

Prevalences of thalassemia/hemoglobinopathies and G-6-PD deficiency in malaria patients.

It seems that thalassemia and/or hemoglobinopathies and glucose-6-phosphate dehydrogenase deficiency (G-6-PD) have some protective effects against malaria infection. To verify this, hemoglobin typing and methehoglobin reduction test were performed on 115 malaria patients and compared with controls. It was found that the number of thalassemia/hemoglobinopathies in the malaria group and in the control group were not significantly different and also occurrence of G-6-PD deficiency in the malaria group was not different from that of the controls. Clinical manifestations of malaria in any group are quite similar. It is concluded that there is no protective effect against malaria in thalassemia/hemoglobinopathies or G-6-PD deficiency.

Association of red cell glucose-6-phosphate dehydrogenase with haemoglobinopathies.

A total of 1,112 randomly selected Saudi Arabs, of both sexes, living in Jeddah and the surrounding areas were screened for the phenotypic distribution of red cell glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD). They were also investigated for haemoglobin and for thalassaemia. Phenotyping of the haemoglobins and the red cell enzymes was carried out by starch gel electrophoresis and the dye-decolouration screening test, while the investigation for thalassaemia was carried out by globin-chain biosynthesis, followed by column chromatography. The red cell Gd- alleles were significantly associated with the sickle-cell gene in both the males (chi 2(1): AS-28.80; SS-4.89) and females (chi 2(1): AS-10.99; SS-13.16). A similar association was also observed between G6PD deficiency and thalassaemias in males (chi 2(1): alpha-thalassaemia - 3.13; beta-thalassaemia - 11.06) and females (chi 2(1): alpha-thalassaemia - 6.63). However, no such association was detected between red cell 6PGD types and haemoglobin genes. The results suggest that the red cell G6PD deficiency, sickle-cell and thalassaemia genes might have evolved as a result of the same ecological factor, probably malaria.

[Prenatal diagnosis of hemoglobinopathies in the 1st and 2nd pregnancy trimesters]. / Diagnosi prenatale di emoglobinopatie nel 1. e 2. trimestre di gravidanza.

Fetal diagnosis of haemoglobinopathies, mainly thalassaemia, is widely used for the prevention of these diseases. Since 1975 fetal diagnosis has been carried out in the second trimester of pregnancy (18th - 22th week) on fetal blood samples obtained by fetoscopy or placentocentesis. The biochemical technique most commonly employed has been represented by carboxymethylcellulose chromatography and more recently in our center by isoelectric focusing of haemoglobins which is a faster and cheaper technique. First-trimester fetal diagnosis is now feasible by DNA analysis on chorionic villi. The Milan center experience in second trimester fetal diagnosis of haemoglobinopathies on more than 300 cases and the preliminary data on first trimester diagnosis are reported.

Increased erythrocyte superoxide dismutase activities in beta 0-thalassaemia/haemoglobin E and in haemoglobin H diseases.

Erythrocyte superoxide dismutase activities were measured in 45 subjects, 15 each of beta 0-thalassaemia/haemoglobin (Hb) E disease, Hb H disease, and normal. The erythrocyte superoxide dismutase activities were significantly higher in the patients with beta 0-thalassaemia/Hb E and Hb H diseases than in the normal subjects. The increase of erythrocyte superoxide dismutase activities is most likely due to abnormalities specific to thalassaemic red cells rather than an increased number of younger red cells for reticulocytes and nucleated red blood cells did not affect the enzyme activity. Patients with beta 0-thalassaemia/Hb E disease with lower haemoglobin concentration had significantly higher superoxide dismutase activities. In all 45 subjects haemoglobin concentrations and superoxide dismutase activities were inversely correlated (r = -0.60 (p less than 0.001)). This indicates that the amounts of superoxide generated in the red cells may, at least partly, determine severity of red cell damage and thus severity of disease; the increased superoxide dismutase activity in thalassaemia is a response to superoxide generated in greater amounts because of accumulation of excessive globin chains and iron in the red cells. The superoxide dismutase activities in Hb H disease, an alpha-thalassaemic disease, were found to be strikingly increased, higher than in beta 0-thalassaemic disease or other conditions.

[Probe test for the detection of hemoglobinopathies and enzyme defect anemias]. / Suchteste zur Erfassung von Hämoglobinopathien und Enzymdefektanämien.

The simplest methods for the diagnosis of thalassaemias are the morphology of erythrocytes, the Hb-F-elution test and the Hb H Heinz bodies test. In order to prove the sickle cell anomaly sickle cell preparation and Hb-S-precipitation test can be performed in every laboratory. By means of the isopropanol precipitation test or the Heinz bodies test can be searched for instable haemoglobins without any laboratory expenditure. On the other hand, haemoglobins with increased oxygen affinity demand a measurement of the oxygen affinity of the erythrocytes. However, simple fluorescence or dye-stuff methods are out our disposal for the most important erythrocytic enzymopenias.

Dapsone-induced methemoglobinemia and hemolysis in the presence of familial hemoglobinopathy Hasharon and familial methemoglobin reductase deficiency.

Methemoglobinemia and hemolysis are well-known side effects after using high doses of dapsone (4,4'-diaminodiphenylsulfone). Their occurrence after low doses of the drug, and subsequent investigation, revealed the presence of hemoglobin Hasharon, and low content of NADH-dependent methemoglobin reductase in five members of an East European ashkenazic Jewish family.

[Congenital hemolytic anemias]. / Angeborene hämolytische Anämien.

During the last years our knowledge of the structural composition of erythrocyte membranes has markedly increased. It is the aim of this review to discuss hereditary changes of the erythrocyte membrane of pathophysiological significance on the basis of these recent biochemical findings. The report particularly deals with structural proteins, such as spectrin, and its possible significance for corpuscular deformation (e. g. spherocytosis). In addition, the importance of hemoglobinopathies and hereditary enzymatic defects for the development of hemolysis is discussed.

Heme synthesis in hereditary hemolytic anemias: decreased delta-aminolevulinic acid synthetase in hemoglobin Köln disease.

The activities of delta-aminolevulinic acid (ALA) synthetase and ALA dehydratase in cord blood erythrocytes of newborn infants and peripheral blood red cells of patients with beta-thalassemia major, beta-thalassemia intermedia, hemoglobin Köln (Hb Köln) disease, sickle cell anemia, and pyruvate kinase deficiency were studied. The activity of ALA dehydratase did not vary appreciably with the number of immature RBC (reticulocytes and nucleated red blood cells) or the severity of the hemolytic anemia except in pyruvate kinase deficiency. The activity of ALA synthetase was linearly correlated with the number of immature RBC (r=0.974, p is less than 0.001). The ALA synthetase activity was significantly decreased in the RBC of Hb Köln (p is less than 0.01) when compared with the activity in immature RBC of newborns and of patients with pyruvate kinase deficiency, sickle cell anemia, and thalassemia intermedia.