Frequency of red blood cell allo-immunization in patients undergoing blood transfusion at the Uganda Cancer Institute.

Background: There is limited data on red blood cell (RBC) alloimmunization in patients with cancer in sub-Saharan Africa (SSA). We examined the frequency of RBC alloimmunization in transfused patients with cancers in Uganda. Methods: A randomized control trial was conducted on participants at the Uganda Cancer Institute. Eligible participants were age ≥15 years and required blood transfusion. Participants were randomized to receive either leucoreduced or non-leucoreduced blood transfusion. Participants' plasma samples were screened for RBC alloantibodies at enrolment and 3-4 weeks after blood transfusion using a 2-cell panel of reagent group O RBCs using the tube method. Antibody identification was performed using a 10-cell panels of reagent RBCs. Participants were considered alloimmunized if antibodies to RBC antigens were identified. Results: A total of 277 participants were randomized (leucoreduced blood, n=137; non-leucoreduced blood, n=140). Overall, the most represented diagnoses were gynaecological cancers (n=88, 31.8%), acute leukaemia (n=35, 12.6%), and gastrointestinal cancers (n=25, 9.0%). Concomitant HIV infection was present in 26 (9.4%) participants. Most participants received <5 units of blood during the study. No study participant developed allo-antibodies. Conclusion: There was no RBC alloimmunization in participants with cancers. Routine RBC allo-antibody screening in all patients with cancer in SSA requires further research.

Implementation of Low Titer Whole Blood for French overseas operations: O positive or negative products in massive hemorrhage?

Massive hemorrhage is the leading preventable cause of death during military operations. During these operations, the delay between initial treatment and arrival at a surgical facility is considerably longer than in Metropolitan settings. This increased prehospital period requires the availability of blood products during the prehospital stage and justifies the availability of Low Titer Whole Blood (LTOWB) for surgical facilities. This product is a fully authorized labile blood product processed by the French Military Blood Institute according to French regulations. Its shelf life is 21 days when stored between 2 and 6°C. It provides the three products necessary for the transfusion management of war injuries in a single product and in physiological proportions. The low anti-A and anti-B titers (<1/64) make LTOWB compatible with any recipient. However, the RhD antigen remains an issue due to its potential harm in cases of transfusion to a D-negative childbearing-age woman due to the potential risk of fetal-maternal incompatibility. This risk must be balanced with the availability of D-negative blood products. Considering the epidemiology of war injuries and LTOWB use guidelines, in addition to the current knowledge on anti-RhD fetal-maternal alloimmunization, the harm-benefit assessment favors the use of RhD-positive LTOWB during overseas operations. Follow-up of childbearing recipients and setup of countermeasures to prevent alloimmunization in those cases remain key points of transfusion safety.

The transfusion of non-prophylactically RH-KEL1 antigen-matched red blood cells is feasible in selected myelodysplastic syndrome and acute myeloid leukaemia patients.

BACKGROUND AND OBJECTIVES: Most myelodysplastic syndromes (MDS) patients become red blood cell (RBC) transfusion-dependent. Transfusing MDS patients with prophylactically RH-KEL1 antigen-matched (PAM) RBC units is recommended to avoid RBC allo-immunization. D+C-E-c+e+, D+C-E+c+e- and D+C+E-c-e+ phenotypes are infrequent among French blood donors. To preserve infrequent phenotype RBC units for patients other than MDS, and to manage frequent phenotype RBC unit stocks, we let, for 1 year, higher-risk non-immunized chronically transfused MDS and acute myeloid leukaemia (AML) patients receive RBC transfusions matched only for D. Our objectives were to evaluate the impact of non-PAM transfusions on the transfusion policy (which would be modified in case of RBC allo-immunization) for frequent and infrequent phenotypes patients and to estimate the number of infrequent phenotypes RBC units that could be redistributed to other patients. RESULTS: Ninety patients were enrolled. Thirty-five patients had infrequent phenotypes, nine received only PAM RBC (143 units) and 26 PAM and non-PAM RBC (415 and 532, respectively): none developed allo-immunization. Fifty-five patients had frequent RBC phenotypes, 34 received only PAM RBC (561 units) and three developed antibodies (2 non-RH-KEL1 and one anti-E); 21 received PAM and non-PAM RBC (436 and 109, respectively) and one developed allo-immunization (unknown specificity). Our strategy enabled us to preserve 532 infrequent phenotypes RBC units: 216 D+C-E-c+e+, 33 D+C-E+c+e- and 283 D+C+E-c-e+ units, representing 48.8% of the total number of RBC units received by infrequent phenotypes patients during the study period. CONCLUSION: Allowing the transfusion of non-PAM RBC in selected chronically transfused MDS and AML patients was feasible and enabled to redistribute infrequent phenotypes RBC units to other patients in need.

Transfusion and sickle cell anemia in Africa.

Sickle cell anemia (SCA) is the commonest life-threatening genetic disorder in tropical regions, particularly in sub-Saharan Africa. It has been estimated that between 50-90% of SCA children will die in Africa before the age of 5, corresponding to a number of 150,000-300,000 annual SCA child deaths, which represents 5-10% of total child mortality. Transfusion support remains an essential component in the management of patients with SCA and has made a significant contribution to improving patient morbidity and mortality. In Africa where the majority of patients with SCA reside, many blood transfusion challenges remains, including shortage of blood supplies, risks related to infectious and immunologic potential side effects and limitation on the diagnosis and management of post-transfusion iron overload. The proportion of transfused SCA patients varies from different studies, between 30% and 90%. This variation can be related to environmental factors, disease genetic factors and other factors including the low availability of blood, difficulties in accessing to health care and inadequacies of the transfusion system. Because blood transfusion therapy is an integral component of the management of SCA, improved efforts and strategies to overcome these challenges and optimize blood transfusion practices are needed in African countries.

Minor blood group incompatibility due to blood groups other than Rh(D) leading to hemolytic disease of fetus and newborn: a need for routine antibody screening during pregnancy.

Minor blood group incompatibility due to blood groups other than Rh(D), although an uncommon cause of neonatal hyperbilirubinemia, has the potential to cause severe hyperbilirubinemia and its sequelae in infants, if left undiagnosed and untreated. Here, we describe clinical presentation, diagnosis and treatment of three cases of minor blood group incompatibility due to anti-E and anti-c antibody. All three neonates presented with pallor, icterus and splenomegaly within the first three days of life. Investigations showed indirect hyperbilirubinemia and a positive direct coombs test. Indirect coombs test was positive in the mothers. There was no setting of ABO or Rh(D) incompatibility in any of the neonates. When tested for minor blood group incompatibility, anti E antibody was found to be responsible for hemolysis and hyperbilirubinemia in the first case, and anti c antibody was found in the second case and third case had both anti c and anti E antibodies. While hyperbilirubinemia improved with intensive phototherapy in the first two cases, the third case required a double volume exchange transfusion. On follow up, bilateral sensorineural hearing loss was seen in one of the patients. All three neonates were otherwise healthy, gaining weight and developmentally normal.

Challenges in preventing and treating hemolytic complications associated with red blood cell transfusion.

Red blood cell (RBC) transfusion support represents a critical component of sickle cell disease (SCD) management. However, as with any therapeutic intervention, RBC transfusion is not without risk. Repeat exposure to allogeneic RBCs can result in the development of RBC alloantibodies that can make it difficult to find compatible RBCs for future transfusions and can directly increase the risk of developing acute or delayed hemolytic transfusion reactions, which can be further complicated by hyperhemolysis. Several prophylactic and treatment strategies have been employed in an effort to reduce or prevent hemolytic transfusion reactions. However, conflicting data exist regarding the efficacy of many of these approaches. We will explore the challenges associated with predicting, preventing and treating different types of hemolytic transfusion reactions in patients with SCD in addition to describing future strategies that may aid in the management of the complex transfusion requirements of SCD patients.

[Outcome of in utero transfusion in case of fœtomaternal red blood cell incompatibility]. / Devenir obstétrical après transfusion in utero pour allo-immunisation fœto-maternelle.

OBJECTIVE: Erythrocyte allo-immunization's rate has decreased but without adapted treatment the prognosis is still poor. The aim of our study was to evaluate the fetal prognosis, the complication's rate and the risk factors of complications of the intrauterine transfusion. METHODS: Retrospective study about 37 fetus and 86 intrauterine transfusions between 2001 and 2017. Our main criterion in judging was the occurrence of procedure related complications: premature membrane rupture or premature delivery within seven days from the procedure, chorioamnionitis, abnormal fetal heart rate indicating an emergency ceasarean section within the 24hours from the procedure, in utero death or neonatal death related to the procedure. RESULTS: The survival rate was about 88.9% with a severe complication's rate of 5.8% per intrauterine transfusion and 13.5% per pregnancy. Intrauterine transfusions before 18 weeks of pregnancies was a complication risk factor: 50% of complications before 18 weeks vs. 1.3%, P=0.8×10-3. On the contrary, hydrops did not seem to be a complication risk factor (16.7% of complication with hydrops vs. 3.9%, P=0.27). The localisation of the needle insertion, intra-abdominal or placental insertion, had no effect on the fetal prognosis. CONCLUSION: Intrauterine transfusion complications are rare and it enhances the fetal prognosis. However, an early procedure is related to a higher rate of complications.

[Caracterization of HLA allo-immunization and clinical impact in transfusion and organ transplantation]. / Caractérisation de l'allo-immunisation anti-HLA et impact clinique en transfusion et en transplantation d'organe.

Allo-immunizations against HLA antigens are known to be deleterious in transfusion and organ transplantation. The development of new tests based on solid phase assays for screening and identification of HLA antibodies in particular those using Luminex® bead based technology has completely changed the way of allo-immunization monitoring because of their extreme sensitivity. They allow a better characterization of these antibodies, identification of acceptable antigens and the use of virtual cross-matches. All these new possibilities improve the managing of patients before and after platelets transfusion or organ transplantation. However, this technology displays some limits that should be known in order to interpret correctly the results. Beside these bead based assays, cellular cross-matches based on Complement Dependent Cytotoxicity (CDC) and flow cytometry are still used and useful in organ transplantation since beads are produced in vitro and do not reflected exactly what happens physiologically. Moreover, differences of sensitivity between these methods make results interpretation and decision making difficult in some cases.

[Is transplantation an alternative to the transfusional impasse in sickle cell disease?] / Dans la drépanocytose, la greffe est-elle une alternative à l'impasse transfusionnelle ?

Sickle cell disease is the most frequent genetic disease in France, concerning 400 newborns each year. The management of these Afro-Caribbean patients requires frequent transfusions from Caucasian donors. Due to important erythroid antigenic differences between Caucasian and African, the prevalence of allo-immunization is high in this population with a risk of transfusional impasse. Allogeneic stem cell transplantation is the only curative treatment for this disease and the replacement of red cells and lymphocytes of the sickle cell patient by those of the donor can also resolve the transfusional impasse. However, a close consultation between physicians from the blood bank and transplantation unit will be required for the choice of conditioning regimen and GvH prophylaxis in order to ensure the transition from a mixed chimerism to the full donor curative graft.

Pattern and prevelence of alloimmunization in multiply transfused patients with sickle cell disease in Nigeria.

BACKGROUND AND STUDY OBJECTIVES: Blood transfusion is central in the prevention and treatment of certain chronic complications of sickle cell disease. It is indispensible in correcting anaemias as well as in the practice of exchange blood transfusion. These gains are largely limited by formation of allo-antibodies. Several studies demonstrated varying frequencies of allo-immunization in various patient groups. The effect of the racial differences between the donor and recipient pool, which has been subsumed in this study, has continuously created a confounding effect on the results of previous studies. AIM: This study was aimed at determining the pattern and frequency of allo-immunization in multiply transfused sickle cell patients, in a racially matched donor and recipient population. PATIENTS AND METHODS: This was a cross-sectional case-controlled study involving 80 Nigerian sickle cell disease patients who had received three or more units of packed red cells in the within 4 weeks of the study and 40 controls (who were SCD that had not been transfused in their life time). Antibody screening and identification was done using the Diamed microtyping system. RESULTS: Frequency of allo-immunization was determined to be 18.7 % (15/80) among the previously transfused and 5 % (15/120) in all sickle cell disease patients. Auto-antibodies were detected in 1.25 % of the study group and 2.5 % of the control, and all reacted with the Kell and Lutheran blood group antigens. The pattern of allo-antibodies found showed; 46.7 % Rhesus, 40 % Kell, while Lutheran and Duffy 13.3 %, each. CONCLUSION: Sickle cell disease patients are particularly susceptible to development of allo-antibodies despite racial similarities between the donor and recipient population. The most common allo-antibodies are Rhesus, Kell and Lutheran and Duffy respectively in order of decreasing frequency. Development of auto-antibodies seems to be independent of blood transfusion in sickle cell disease with possibly different pathogenetic mechanism. Policy on extended red cell phenotyping for common antigens will reduce allo-immunization among multiply transfused patients.

Approach to a case of multiple irregular red cell antibodies in a liver transplant recipient: Need for developing competence.

Liver transplant procedure acts as a challenge for transfusion services in terms of specialized blood components, serologic problems, and immunologic effects of transfusion. Red cell alloimmunization in patients awaiting a liver transplant complicate the process by undue delay or unavailability of compatible red blood cell units. Compatible blood units can be provided by well-equipped immunohematology laboratory, which has expertise in resolving these serological problems. This report illustrates resolution of a case with multiple alloantibodies using standard techniques, particularly rare antisera. Our case re-emphasizes the need for universal antibody screening in all patients as part of pretransfusion testing, which helps to identify atypical antibodies and plan for appropriate transfusion support well in time. We recommend that the centers, especially the ones that perform complex procedures like solid organ transplants and hematological transplants should have the necessary immunohematological reagents including rare antisera to resolve complex cases of multiple antibodies as illustrated in this case.

[Platelet allo-antibodies identification strategies for preventing and managing platelet refractoriness]. / Stratégies d'exploration de l'allo-immunisation plaquettaire pour la prévention et la prise en charge des inefficacités transfusionnelles plaquettaires.

Platelet refractoriness is a serious complication for patients receiving recurrent platelet transfusions, which can be explained by non-immune and immune causes. Human Leukocyte Antigens (HLA) allo-immunization, especially against HLA class I, is the major cause for immune platelet refractoriness. To a lesser extent, allo-antibodies against specific Human Platelet Antigen (HPA) are also involved. Pregnancy, transplantation and previous transfusions can lead to allo-immune reaction against platelet antigens. After transfusion, platelet count is decreased by accelerated platelet destruction related to antibodies fixation on incompatible platelet antigens. New laboratory tests for allo-antibodies identification were developed to improve sensibility and specificity, especially with the LUMINEX(®) technology. The good use and interpretation of these antibodies assays can improve strategies for platelet refractoriness prevention and management with a patient adapted response. Compatible platelets units can be selected according to their identity with recipient typing or immune compatibility regarding HLA or HPA antibodies or HLA epitope compatibility. Prospective studies are needed to further confirm the clinical benefit of new allo-antibodies identification methods and consensus strategies for immune platelet refractoriness management.

Allo-antibody identification: a software approach!

BACKGROUND: Unexpected allo-antibody identification is difficult serological test requiring in-depth knowledge of antibody behavior, identification rules, knowledge of zygosity of antigens and dosage phenomenon. Software which uses an algorithm based on characteristics of antibodies is now available to interpret specificity of allo-antibody. A study was undertaken to evaluate the effectiveness of one such software (Resolvigen) for antibody identification compared with manual antibody identification method. MATERIALS AND METHODS: The study was a retrospective observational study where 238 allo-antibody results were re-evaluated using Resolvigen software (Ortho Clinical Diagnostics, Johnson and Johnson, Raritan, NJ, USA) and agreement between manual and software approaches was studied. Resolvigen software was also evaluated for usefulness, ease of use and predicted future usage by administering investigators a questionnaire with Likert scale. RESULTS: Agreement between the results of manual and automated methods ranged from 98.6% for single antibody to 65% for two antibodies (p = 0.000). Resolvigen software came out as very useful, easy to use, and with high predicted future usage. CONCLUSION: This study concludes that Resolvigen can either replace manual method or be used as adjuvant to routine manual method.

[Non-invasive fetal RHD genotyping: Validation of the method with 200 patients]. / RHD fœtal sur plasma maternel : validation de méthode sur 200 patientes.

BACKGROUND: Non-invasive fetal RHD genotyping is an important tool to assess the risk of fetuse's hemolytic disease of anti-D allo-immunized pregnant woman by non-invasive method. A method of genotyping has been developed in the laboratory of Lyon-GHE according to Minon's team (J Gynecol Obstet Biol Reprod 2005): exon 4, 5, and 10 are amplified by real time PCR. At first, genotyping results of 200 pregnant women have been compared with RH1 phenotype at birth. The most important parameters of validation have been tested: the sensibility and the specificity; the negative predictive value; the correlation study permitted to define criteria of biological interpretation. The validation of this method permitted to determine critical points and the limits of the method due to the minor amount of fetal DNA in the maternal plasma and existence of many variant forms of the RHD gene. CONCLUSION: We worked too in the perspective to the accreditation for our genetic laboratory.

Presensitization revisited: pitfalls of vascular allografts in transplant candidates.

Vascular allografts in end-stage renal disease (ESRD) patients represent a particular immunological challenge. A broad HLA immunization led us to study in depth the history of two patients with vascular allografts. In Case 1 the allograft was added to a Gore-Tex graft used for haemodialysis access and no immunosuppression was administered. In Case 2 the allograft was used to prolong a renal artery from living donor and immunosuppression was suboptimal. In vascular surgery, immunosuppression is mainly used to improve graft patency. ESRD patients are potential organ recipients and immunosuppression should therefore be tailored to reduce HLA immunization.