Simple PCR detection of haptoglobin gene deletion in anhaptoglobinemic patients with antihaptoglobin antibody that causes anaphylactic transfusion reactions.
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Two anhaptoglobinemic patients showing anaphylactic transfusion reactions by antihaptoglobin antibody were found. Southern blot analysis indicated that 2 patients were homozygous for the deleted allele of the haptoglobin gene (Hp(del)) as reported previously. We have identified the junction region of the deletion from genomic DNA of 1 patient using cassette-mediated polymerase chain reaction (PCR). Then, the deleted region from the 5' breakpoint to the promoter region of the Hp was amplified from genomic DNA of a control individual using PCR. DNA sequence analysis of these regions indicated that the 5' breakpoint of the Hp(del) allele was located 5. 2 kilobase (kb) upstream of exon 1 of the Hp and the 3' breakpoint was positioned between 52 and 53 base pair (bp) upstream of exon 5 of the haptoglobin-related gene. There was no significant homology between the DNA sequences flanking the 5' and 3' breakpoints, except for a 2-bp (TG) identity. To examine the gene frequency, we have developed a simple PCR method to detect the gene deletion. We found 8, 16, and 17 Hp(del) alleles in 157 Koreans, 523 Japanese, and in 284 Chinese, respectively, but did not find the Hp(del) in 101 Africans or in 100 European-Africans. The incidence of individuals homozygous for the Hp(del) allele was therefore expected to be 1/4000 in Japanese, 1/1500 in Koreans, and 1/1000 in Chinese. This incidence is higher than that of IgA deficiency in Japanese. More attention should be paid on haptoglobin deficiency and antihaptoglobin antibody as the cause of transfusion-related anaphylactic reactions in Asian populations. (Blood. 2000;95:1138-1143) (+info)
Effect of recombinant human erythropoietin combined with granulocyte/ macrophage colony-stimulating factor in the treatment of patients with myelodysplastic syndrome. GM/EPO MDS Study Group.
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This randomized, placebo-controlled trial was designed to assess the efficacy and safety of therapy with granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin (epoetin alfa) in anemic, neutropenic patients with myelodysplastic syndrome. Sixty-six patients were enrolled according to the following French-American-British classification: refractory anemia (20), refractory anemia with excess blasts (35), refractory anemia with ringed sideroblasts (9), and refractory anemia with excess blasts in transformation (2). Patients were stratified by their serum erythropoietin levels (less than or equal to 500 mU/mL, n = 37; greater than 500 mU/mL, n = 29) and randomized, in a 2:1 ratio, to either GM-CSF (0.3-5.0 microg/kg.d) + epoetin alfa (150 IU/kg 3 times/wk) or GM-CSF (0.3-5.0 microg/kg.d) + placebo (3 times/wk). The mean neutrophil count rose from 948 to 3831 during treatment with GM-CSF +/- epoetin alfa. Hemoglobin response (increase greater than or equal to 2 g/dL, unrelated to transfusion) occurred in 4 of 45 (9%) patients in the GM-CSF + epoetin alfa group compared with 1 of 21 (5%) patients with GM-CSF + placebo group (P = NS). Percentages of patients in the epoetin alfa and the placebo groups requiring transfusions of red blood cells were 60% and 92%, respectively, for the low-endogenous erythropoietin patients and 95% and 89% for the high-endogenous erythropoietin patients (P = NS). Similarly, the average numbers of units of red blood cells transfused during the 12-week study in the epoetin alfa and the placebo groups were 5.9 and 9.5, respectively, in the low-endogenous erythropoietin patients and 9.7 and 8.6 in the high-endogenous erythropoietin patients (P = NS). GM-CSF +/- epoetin alfa had no effect on mean platelet count. Treatment was well tolerated in most patients, though 10 withdrew from the study for reasons related predominantly to GM-CSF toxicity. (Blood. 2000;95:1175-1179) (+info)
Prospective investigation of transfusion transmitted infection in recipients of over 20 000 units of blood. TTI Study Group.
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OBJECTIVES: To follow up recipients of 20 000 units of blood to identify any transmissions of infections through blood transfusion. DESIGN: Follow up study of recipients of transfusion. SETTING: 22 hospitals in north London. PARTICIPANT: Adult patients who had recently been transfused. MAIN OUTCOME MEASURES: Patients had further blood samples taken at 9 months that were tested for markers of hepatitis B and C and HIV and human T cell leukaemia/lymphoma virus type I or II (HTLV) infections. Recent infections were distinguished from pre-existing infections by comparison with blood samples taken before transfusion. RESULTS: 9220 patients were recruited, and 5579 recipients of 21 923 units of blood were followed up. No transfusion transmitted infections were identified. The incidence of transfusion transmitted infections was 0 in 21 043 units (95% confidence interval for risk 0 to 1 in 5706 recipients) for hepatitis B; 0 in 21 800 units (0 to 1 in 5911 recipients) for hepatitis C; 0 in 21 923 units (0 to 1 in 5944 recipients) for HIV; and 0 in 21 902 units (0 to 1 in 5939 recipients) for human T cell leukaemia/lymphoma virus. Three patients acquired hepatitis B during or after hospital admission but not through transfusion; 176 (3%) had pre-existing hepatitis B infection. Sixteen (0.29%) patients had hepatitis C, and five (0.09%) had human T cell leukaemia/lymphoma virus. CONCLUSIONS: The current risk of transfusion transmitted infections in the United Kingdom is very small, though hospital acquired infections may arise from sources other than transfusion. A considerable proportion of patients have pre-existing infections. (+info)
Use of tranexamic acid for an effective blood conservation strategy after total knee arthroplasty.
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We have investigated the effect of treatment with tranexamic acid, an inhibitor of fibrinolysis, on blood loss, blood transfusion requirements and blood coagulation in a randomized, double-blind, placebo-controlled study of 42 patients after total knee arthroplasty. Tranexamic acid 15 mg kg-1 (n = 21) or an equivalent volume of normal saline (n = 21) was given 30 min before surgery and subsequently every 8 h for 3 days. Coagulation and fibrinolysis values, blood loss and blood units administered were measured before administration of tranexamic acid, 8 h after the end of surgery and at 24 and 72 h after operation. Coagulation profile was examined (bleeding time, platelet count, prothrombin time (PT), activated partial thromboplastin time (aPTT), plasminogen, beta-thromboglobulin and fibrinogen). Fibrinolysis was evaluated by measurement of concentrations of D-dimer and fibrinogen degradation products (FDP). Total blood loss in the tranexamic acid group was 678 (SD 352) ml compared with 1419 (607) ml in the control group (P < 0.001), and occurred primarily during the first 24 h after surgery. Thirteen patients received 1-5 u. of packed red blood cells in the control group compared with two patients in the tranexamic acid group, who received 3 u. (P < 0.001). Postoperative packed cell volume values were higher in the tranexamic acid group despite fewer blood transfusions. Postoperative concentrations of plasminogen were decreased significantly in the tranexamic acid group (P < 0.001). Platelet count, PT, aPTT, bleeding time, beta-thromboglobulin, fibrinogen and FDP concentrations did not differ between groups, but D-dimer concentrations were increased in the control group. Thromboembolic complications occurred in two patients in the control group compared with none in the tranexamic acid group. (+info)
Blood recipient notification for hepatitis C in Prince Edward Island.
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BACKGROUND: Two of the major risk factors for hepatitis C are injection drug use and receipt of blood or blood products. Many patients are unaware that they have received transfusions. In 1998 Prince Edward Island conducted a province-wide look-back notification program to notify patients who had received transfusions in PEI between Jan. 1, 1984, and June 1, 1990. The authors present the results of the notification program. METHODS: A registry for recipients of blood and blood products was created from the province's Red Cross blood bank records. The registry data were linked with Vital Statistics data to determine death status and with Health Registration data to determine residence status of recipients (in PEI or moved out of province). All identified recipients with a current PEI mailing address were sent a letter recommending hepatitis C virus (HCV) testing. Laboratory records were checked to determine HCV test results. RESULTS: The registry contained data for 6086 recipients of blood or blood products during the look-back period; 51.1% (3109/6086) had died by the time of notification. Of the remainder, 18.4% (549/2977) were not directly notified because they had moved out of province, had refused delivery of the notification letter or had died recently, or because identifying information was missing from the blood bank records. Of the recipients who were notified 80.4% (1953/2428) underwent testing, and 2.2% (43/1953) were found to be HCV positive. Most of these (58.1% [25/43]) had undergone testing before notification. The HCV positivity rate differed significantly between recipients tested before notification and those tested after notification (9.9% v. 1.1%, p < 0.001). HCV-positive recipients were more likely than other notified recipients to have had multiple transfusions (39.5% v. 9.5%, p < 0.001). INTERPRETATION: Before notification 4.1% of PEI recipients had undergone HCV testing. After notification 91.2% of PEI recipients were identified as tested, dead or moved out of province. The notification program resulted in the identification of the majority of PEI's transfusion-related cases of hepatitis C. (+info)
Prevention of transfusional Trypanosoma cruzi infection in Latin America.
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Trypanosoma cruzi is a protozoan infection widely spread in Latin America, from Mexico in the north to Argentina and Chile in the south. The second most important way of acquiring the infection is by blood transfusion. Even if most countries of Latin America have law/decree/norms, that make mandatory the screening of blood donors for infectious diseases, including T. cruzi (El Salvador and Nicaragua do not have laws on the subject), there is usually no enforcement or it is very lax. Analysis of published serologic surveys of T. cruzi antibodies in blood donors done in 1993, indicating the number of donors and screening coverage for T. cruzi in ten countries of Central and South America indicated that the probability of receiving a potentially infected transfusion unit in each country varied from 1,096 per 10,000 transfusions in Bolivia, the highest, to 13.02 or 13.86 per 10,000 transfusions in Honduras and Venezuela respectively, where screening coverage was 100%. On the other hand the probability of transmitting a T. cruzi infected unit was 219/10,000 in Bolivia, 24/10,000 in Colombia, 17/10,000 in El Salvador, and around 2-12/10,000 for the seven other countries. Infectivity risks defined as the likelihood of being infected when receiving an infected transfusion unit were assumed to be 20% for T. cruzi. Based on this, estimates of the absolute number of infections induced by transfusion indicated that they were 832, 236, and 875 in Bolivia, Chile and Colombia respectively. In all the other countries varied from seven in Honduras to 85 in El Salvador. Since 1993, the situation has improved. At that time only Honduras and Venezuela screened 100% of donors, while seven countries, Argentina, Colombia, El Salvador, Honduras, Paraguay, Uruguay and Venezuela, did the same in 1996. In Central America, without information from Guatemala, the screening of donors for T. cruzi prevented the transfusion of 1,481 infected units and the potential infection of 300 individuals in 1996. In the same year, in seven countries of South America, the screening prevented the transfusion of 36,017 infected units and 7, 201 potential cases of transfusional infection. (+info)
Chagas infection transmission control: situation of transfusional transmission in Brazil and other countries of Latin America.
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The transmission of the transfusion-associated Chagas disease is an important mechanism of its dissemination in several Latin American countries. The transmission risk depends on five factors: prevalence of infection in blood donors, degree of serological coverage, sensibility of used tests, safety of obtained results and infection risk. The Southern Cone Iniciative set off by the Pan-American Health Organization, in 1991, is contributing to the implementation of blood law in each endemic country, and to reduce the risk of transfusional transmission of this horrible disease. Despite the clear improvement of Brasilian hemotherapy after 1980 (with the creation of the Blood National Program - Pro-Sangue) and the significant reduction of the chagasic infection among its blood donors; socio-economic, politic and cultural unlevels, prevent it from reaching the necessary universality and security. In order to assure both, the Brazilian Ministry of Health decided to restructure its blood system. In May, 1998, a great program was launched, to reach a specific goal: Blood - 100% with quality safety in all its process until 2003. It was divided in 12 projects, intends to guarantee the quality and self sufficiency in blood and hemoderivates. (+info)
Specific B cell tolerance is induced by cyclosporin A plus donor-specific blood transfusion pretreatment: prolonged survival of MHC class I disparate cardiac allografts.
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Donor-specific blood transfusion (DST), designed to prolong allograft survival, sensitized recipients of the high-responder PVG-RT1u strain, resulting in accelerated rejection of MHC-class I mismatched (PVG-R8) allografts. Rejection was found to be mediated by anti-MHC class I (Aa) alloantibody. By pretreating recipients 4 wk before grafting with cyclosporin A (CsA) daily (x7), combined with once weekly (x4) DST, rejection was prevented. The investigation explores the mechanism for this induced unresponsiveness. CD4 T cells purified from the thoracic duct of CsA/DST-pretreated RT1u rats induced rejection when transferred to R8 heart-grafted RT1u athymic nude recipients, indicating that CD4 T cells were not tolerized by the pretreatment. To determine whether B cells were affected, nude recipients were pretreated, in the absence of T cells, with CsA/DST (or CsA/third party blood) 4 wk before grafting. The subsequent transfer of normal CD4 T cells induced acute rejection of R8 cardiac allografts in third party- but not DST-pretreated recipients; prolonged allograft survival was reversed by the cotransfer of B cells with the CD4 T cells. Graft survival correlated with reduced production of anti-MHC class I (Aa) cytotoxic alloantibody. The results indicated that the combined pretransplant treatment of CsA and DST induced tolerance in allospecific B cells independently of T cells. The resulting suppression of allospecific cytotoxic Ab correlated with the survival of MHC class I mismatched allografts. The induction of B cell tolerance by CsA has important implications for clinical transplantation. (+info)