Blood transfusion erythrocytes

During blood transfusions, immune reactions can occur that destroy the erythrocytes transfused from the donor. These reactions result from the formation of antibodies (see p. 300) directed to certain surface structures on the erythrocytes. Known as blood group antigens, these are proteins or oligosaccharides that can differ from individual to individual. More than 20 different blood group systems are now known. The ABO system and the Rh system are of particular clinical importance. 

Patients who have blood transfusion malaria are infected with the asexual erythrocytic parasites only exoerythrocytic tissue forms apparently do not develop. Plasmodium malariae has been known to produce an infection after transfusion, even when the blood was obtained from a person whose only contact with malaria was 40 years previous to the donation of blood. 

Increased plasmalogen levels have not been observed. Erroneously low red cell levels can be encountered when the transmethylation process has not been completed. Breaking the ether lipid bond of the plasmalogens requires more energy than hydrolysis of the fatty acid esters. Evaluation of the plasmalogen levels should not be done after a blood transfusion. Donor erythrocytes will be present for up to 120 days following a transfusion. 

The first approval of a therapeutic use for recombinant EPO was in 1989 for the treatment of anemia related to chronic renal failure. The treatment with EPO stimulates production of erythrocytes and improves the patient s quality of life, as well as reducing or eliminating the need for blood transfusion. There are other non-renal applications, such as the minimization of blood transfusion after surgery, the prevention of anemia after bone marrow transplantation, and the treatment of anemia caused by the use of antiretroviral drugs, by chemotherapy, and by prematurity. 

Hydroxyurea (hydroxycarbamide) is the first widely available and affordable agent that provides real benefit. It acts by perturbing the maturation of erythrocytes and promoting HbF production. The mode of action may be more complex reduction in leukocyte counts may reduce vaso-occlusive events reduced red cell and endothelial adhesiveness may be a direct effect. Beneficial effects have been seen in adults, children and mfants. Long-term hydrox5mrea (hydroxycarbamide) (at close to myelotoxic doses) raises FIbF to 15-20% and reduces the frequency of hospitalisation, pain, acute chest syndrome and blood transfusion. Neurological complications e.g. stroke, may not be reduced. Some 10-20% of patients will fail to respond due to the condition of the bone marrow, or genetic effects (see also p. 607,613). 

Blood transfusions Haemolysis is due to the shortened lifespan of transfused erythrocytes. 

Other pitfalls in correct diagnosis of glycolytic enzyme deficiencies include the red cell age dependency of enzymes such as PK, HK, and G6PD. The measurement of these enzymes simultaneously can give an idea about red cell age and relative deficiencies. Many patients suffering from severe hemolysis have already received blood transfusions. When this occurs, interpreting results from red cell enzyme aissays must be done with great care, since the. presence of donor erythrocytes wdl obscme any deficiencies. In addition, some mutant enzymes display a normal activity in vitro, while in vivo severe hemolysis can occur. More sophisticated assays to measure, for example, heat instability and kinetics have to be used in those cases. 

There is no cure for sickle cell disease and current therapies are aimed at managing the nnmerons complications associated with the condition. These therapies inclnde penicillin treatment, iimnunization against Streptococcus pneumoniae, blood transfusions, and hydroxyurea (12,20). Hydroxyurea is the only drug therapy specific for sickle cell disease. Hydroxyurea appears to act through several mechanisms, including increased production of fetal hemoglobin, reduced adhesion of blood cells to endothelial cells, improved erythrocyte hydration, and reduced neutrophil counts (21). Hydroxyurea has proven effective but there are some concerns with toxicity and not all patients respond to the treatment (21-23). There is clearly a need for development of additional therapies. 

Whole blood transfusions may be administered. Alternatively, erythropoietin may be given to stimulate the production of erythrocytes. 

The stones and rine were analysed for purine content by methods described previously The stones were reported to be uric acid by thermogravimetric anlysis but spectral analysis showed 2.8 dihydroxy-adenine. The urine contained 2.8 dihydrosyadenine, 8-hydroxyadenine and adenine in addition to the normal purines. APRT activity in S.B., the mother and sister was measured in lysed erythrocytes. This was initially raised in S.B. because of the recent blood transfusion but... 

Enzymes Caffeine-free or Erythrocytes Room tempera- a) Blood transfusion... 

BLOOD TRANSFUSION [SEDA5, 529 SEDA-33, 671 SEDA-34, 509 SEDA-35, 583] Erythrocytes... 

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