Sickle cell disease: a review.

The substitution of one amino acid in the hemoglobin molecule results in sickle hemoglobin. As a result, RBCs sickle in low oxygen states causing occlusion of blood vessels, increased viscosity, and inflammation. These RBCs are prematurely removed from the circulation, resulting in a chronic hemolytic anemia. With newborn screening and early treatment, the death rate among children with SCD has declined. In addition, a variety of treatments are being introduced to help manage the various manifestations of disease. Transfusion, simple or exchange, is a mainstay of therapy, since it reduces the amount of Hgb S in circulation and suppresses erythropoiesis. Transfusion is indicated for symptomatic anemia and specifically to prevent stroke (first or recurrent), during acute stroke, and for acute chest syndrome. Unfortunately, transfusion carries risks for infectious disease transmission, as well as immunologic and inflammatory sequelae. For patients with SCD who may be chronically transfused, iron overload occurs frequently. In addition, due to differences in RBC antigens between donors and recipients, these patients are at increased risk for development of RBC alloantibodies, which can complicate further transfusion. It is, therefore, important to prevent alloimmunization by transfusing leukoreduced RBCs that match the patient for the C, E, and K1 antigens. Human progenitor cell (from bone marrow, peripheral blood stem cells, or umbilical blood) transplant can cure the disease, and is used for patients with severe disease for whom conventional therapy may not be effective.

Cost analysis of erythropoietin versus blood transfusions for cervical cancer patients receiving chemoradiotherapy.

PURPOSE: Red blood cell (RBC) transfusions or erythropoietin (EPO) can be used to evade the detrimental effects of anemia during radiotherapy, but the economic consequences of selecting either intervention are not well defined. The RBC transfusion needs during chemoradiotherapy for cervix cancer were quantified to allow comparison of RBC transfusion costs with the projected cost of EPO in this setting. METHODS AND MATERIALS: For patients receiving pelvic radiotherapy, weekly cisplatin, and brachytherapy, the RBC units transfused during treatment were tallied. RBC transfusion costs per unit included the blood itself, laboratory fees, and expected value (risk multiplied by cost) of transfusion-related viral illness. EPO costs included the drug itself and supplemental RBC transfusions when hemoglobin was not adequately maintained. An EPO dosage based on reported usage in cervix cancer patients was applied. RESULTS: Transfusions were given for hemoglobin <10 g/dL. Among 12 consecutive patients, 10 needed at least 1 U of RBC before or during treatment, most commonly after the fifth week. A total of 37 U was given during treatment, for an average of 3.1 U/patient. The sum total of the projected average transfusion-related costs was $990, compared with the total projected EPO-related costs of $3869. CONCLUSIONS: Because no proven clinical advantage has been documented for EPO compared with RBC transfusions to maintain hemoglobin during cervix cancer treatment, for most patients, transfusions are an appropriate and appealingly less expensive option.

Detection of cytomegalovirus antibodies in serum using the TranSTAT-CMV and CMV Scan assays.

Two hundred serum samples were tested with two assays for rapid detection of cytomegalovirus (CMV) antibodies. The assays were CMV Scan, a two-step latex particle agglutination assay for CMV IgG and IgM antibodies, and TranSTAT-CMV, a newly available six-step solid-phase enzyme immunoassay for CMV IgG antibodies. Comparison of initial results to reference results revealed a sensitivity/specificity of 97.2%/96.8% for CMV Scan and 94.3%/83.0% for TranSTAT-CMV. The same comparison after testing discrepant samples in duplicate increased the sensitivity/specificity to 99.1/100% for CMV Scan and 100%/93.6% for TranSTAT-CMV. Borderline-positive results were observed much more frequently with TranSTAT-CMV than CMV Scan (35 vs. 2), compromising easy interpretation of results. CMV Scan is superior to TranSTAT-CMV on the basis of performance characteristics, simplicity of test performance, and ease of interpretation of results.

Optimization for detection of cytomegalovirus by the polymerase chain reaction (PCR) in clinical samples.

PCR is 100 times more sensitive than traditional tube culture for detecting cytomegalovirus (CMV) but may require up to 12 reactions per specimen (Sandin et al., 1991). In order to make the assay practical for use in a clinical laboratory the procedure used to detect CMV must be simplified. In this study, the effect of reducing the number of reactions per specimen on sensitivity and specificity of the PCR assay was evaluated. 53 residual samples from specimens processed for CMV by shell vial assay/routine tube tissue culture (SVA/TTC) were analyzed by PCR. The residual samples were separated into a supernatant and pellet fractions, then tested for CMV with primers to the immediate early (IEP) and late protein (LP) genes using a nested procedure. To exclude false negatives due to the presence of inhibitors in the sample fractions, all fractions were tested for the presence of the human myosin heavy chain gene also using a nested procedure. SVA/TTC had a sensitivity and specificity of 52/96% in comparison to PCR when data from all 12 PCR reactions was considered. However, high sensitivity and specificity were retained when only the data of the IEP primers with two samples were considered. The results from examining only the 1:10 dilution of pellet and the undiluted supernatant by PCR provided a 60% increase in sensitivity over SVA/TTC, high specificity and a clinically feasible assay.

Presence of the red cell alloantibody anti-E in an 11-week-old infant.

The development of red cell (RBC) alloantibodies in infants less than 4 months of age is believed to be rare. Though there are no well-documented published accounts, the formation of alloanti-E in a multiply transfused 11-week-old infant is reported here. The infant, blood group B, D +, developed necrotizing enterocolitis and renal failure requiring 31 transfusions of washed and unwashed RBCs (group B and group O), as well as fresh-frozen plasma and platelets. Six weeks after the first blood transfusion, alloanti-E was detected. The anti-E weakly agglutinated R2R2 screening RBCs at 37 degrees C and sensitized these RBCs to react with anti-IgG. The infant's RBCs were typed as E-. Passive transfer of alloanti-E was ruled out by the negative antibody screening tests of each donor unit and the absence of any RBC alloantibodies in the mother's serum. Stored samples of the infant's sera were tested, and anti-E was shown to be present approximately 11 days after exposure to a known E+ RBC unit. The appearance of alloanti-E in this time frame is consistent with a secondary immune response. Primary immunization most likely took place in the first 4 weeks of transfusion therapy.