[ABO incompatibility and complications in hematopoietic stem cell transplantation]

Background

Hematopoietic stem cell transplants (HSCT) can be performed regardless of the ABO group compatibility between donor and recipient. ABO incompatibility in HSCT is related to pure red cell aplasia (PRCA), or passenger lymphocyte syndrome. The impact of ABO incompatibility on graft-versus-host disease and transplant-related mortality is controversial due to the heterogeneity of procedures carried out in different transplant centers.

Objective

To determine the prevalence of ABO incompatibility and its complications in a hematopoietic stem transplant unit.

Material and methods

An observational, retrospective study was carried out in patients undergoing HSCT from January 2014 to January 2020. All trasplant patients were included. Qualitative variables were analyzed using chi-squared test, and Wilcoxon and Student's t tests were used for quantitative variables. A p < 0.05 was considered significant.

Results

124 patients undergoing HSCT were analyzed, out of which 31 had ABO incompatibility, with a punctual prevalence of 24.4%; among them, 54% presented with major incompatibility, 32% minor incompatibility and 13% bidirectional incompatibility. Three cases of PRCA were reported. There were no differences in survival at one year in both groups.

Conclusions

The ABO incompatibility ant its complications were not related to the increase in mortality. Randomized prospective studies are required to define the role of ABO incompatibility in HSCT prognosis.

Role of complement in alloimmunization and hyperhemolysis

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of complement in regulating the removal of a target alloantigen following an incompatible red blood cell (RBC) transfusion, the formation of alloantibodies following RBC alloantigen exposure, and the development of hyperhemolysis in patients with sickle cell disease (SCD).

RECENT FINDINGS

Recent studies demonstrate that complement can accelerate alloantibody-mediated removal of target alloantigens from the RBC surface following incompatible transfusion. Complement also influences alloantigen availability during developing alloimmune responses and serves as a unique mediator of CD4 T-cell-independent alloantibody formation following RBC alloantigen exposure. Finally, alternative complement pathway activation appears to play a key role in the development of acute hemolytic episodes in patients with SCD, providing a potential druggable target to prevent acute complications in patients with this disease.

SUMMARY

Recent studies suggest that complement can regulate a wide variety of processes germane to hematology, from transfusion complications to baseline hemolysis in patients with SCD. As the role of complement in various disease processes becomes more fully understood, the ability to leverage recently developed complement modulating drugs will only continue to enhance providers' ability to favorably intervene in many hematological diseases.

ABO hemolytic disease of newborn : Does newborn's blood group a risk factor?

BACKGROUND

Due to the marked decline of maternal-fetal rhesus incompatibility, ABO alloimmunization has become the leading cause of the newborn hemolytic disease. It is estimated that 15-25 % of all pregnancies are concerned by ABO incompatibility.

AIM

Neonatal blood group B seems to be more predisposing to acute hemolysis and severe hyperbilirubinemia. We propose to find if the newborn's blood group B represents a risk factor for severe hemolysis and/or severe hyperbilirubinemia.

METHODS

We conducted a comparative study in the pediatrics department "B" of the Children Hospital of Tunis. We collected retrospectively the medical files of the newborn hospitalized for ABO alloimmunization (January 2011 - March 2014), then we compared two groups, OA group with OA alloimmunization and OB group with OB alloimmunization. A significant threshold was fixed to 0.05.

RESULTS

We collected 98 cases of newborn ABO hemolytic disease. Both groups, OA and OB, were similar for the onset of jaundice, age of hospitalization, initial hemoglobin and indirect bilirubin levels. There were no statistically significant difference in the severity of hyperbilirubinemia and the use of exchange transfusion for the two groups. However, transfusion was statistically more frequent in the OB group compared to OA group (81.6‰ vs 10.2‰, p = 0,039, OR=2.9, 95% IC (1.1 - 7.8)).

CONCLUSION

OB alloimmunization seems to induce more active hemolysis than OA one, with no difference for severe hyperbilirubinemia in both groups.

Hemolytic transfusion reaction attributable to anti-Dia

In situations when a patient's antibody detection test is negative, many institutions have moved from an indirect antiglobulin test (IAT) crossmatch to an electronic crossmatch system. Here we report a case of an acute hemolytic transfusion reaction attributable to anti-Dia in a patient with a negative antibody detection test. A 22-year-old female patient with a diagnosis of β thalassemia and sickle cell anemia commenced a routine exchange transfusion of 5 units of red blood cells (RBCs) in the apheresis unit as part of her regular treatment. When the patient started receiving the implicated unit, she reported back pain, chest pain, and a feeling of anxiety, suggestive of an acute transfusion reaction. The transfusion was ceased and an investigation of an adverse event was commenced. This case illustrates that the presence of antibodies to low-prevalence antigens remains a significant issue for transfusion-dependent individuals. To prevent other transfusion reactions by anti-Dia, the addition of Di(a+) cells to the reagent RBCs used for the antibody detection test along with IAT-crossmatching of donor units for all patients with sickle cell disease is recommended.

Passenger lymphocyte syndrome in ABO and Rhesus D minor mismatched liver and kidney transplantation: A prospective analysis

The increasing demand for solid organs has necessitated the use of ABO and Rhesus (Rh) D minor mismatched transplants. The passenger lymphocyte syndrome (PLS) occurs when donor lymphocytes produce antibodies that react with host red blood cell (RBC) antigens and result in hemolysis. Our aim was to evaluate prospectively the role of PLS in post transplant anemia and hemolysis in ABO and RhD minor mismatched recipients of liver and kidney grafts and to study the association of PLS with donor lymphocyte microchimerism. We examined 11 liver and 10 kidney recipients at Day +15 for anemia, markers of hemolysis, direct antiglobulin test and eluates, and serum RBC antibodies. Microchimerism was determined in peripheral blood lymphocytes by genotyping of simple sequence length polymorphisms encoding short tandem repeats. Immune hemolytic anemia and anti-recipient RBC antibodies were observed in 2 out of 11 liver (18.2%) and 2 out of 10 kidney (20%) transplants. RBC antibody specificity reflected the donor to recipient transplant, with anti-blood group B antibodies identified in 2 cases of O to B and 1 case of A to AB transplants while anti-D antibodies were detected in 1 case of RhD-negative to RhD-positive transplant. Donor microchimerism was found in only 1 patient. In conclusion, passenger lymphocyte mediated hemolysis is frequent in minor mismatched liver and kidney transplantation. Recognizing PLS as a potential cause of post transplant anemia may allow for early diagnosis and management to decrease the morbidity and mortality in some patients.

Clinical features and risk factors of pure red cell aplasia following major ABO-incompatible allogeneic hematopoietic stem cell transplantation

The objective of this paper was to study the incidence, risk factors, clinical outcome, management and prevention of pure red cell aplasia (PRCA) following major ABO-incompatible allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed 11 cases of PRCA from a series of 42 patients undergoing major ABO-incompatible allo-HSCT from April 1997 to December 2005. Eleven out of the 42 patients developed PRCA (26.1%). All the 11 cases of PRCA were in blood group O recipients of grafts from blood group A donor (n = 9) or blood group B donor (n = 2). The following factors were associated with an increased risk of PRCA: (1) blood group O recipient; (2) blood group A donor; and (3) blood group O/A in recipient/donor pair. Only blood group O/A in recipient/donor pair was identified as being significantly associated with the occurrence of PRCA by multivariate analysis. Six patients who received donor-type plasma exchange did not develop PRCA and among them 5 cases were the blood group O recipients. Eight patients obtained spontaneous remission and in the remaining 3 patients 2 with long-lasting PRCA were successfully treated with plasma exchange with donor-type plasma replacement and the other one who was also complicated by EBV-associated lymphoproliferative disorder (EBV-PTLD) responded rapidly to anti-CD20 monoclonal antibody and achieved complete resolution of clinical finding and symptom of both EBV-PTLD and PRCA. We conclude that blood group A/O in donor/recipient pair is identified as being significantly associated with the occurrence of PRCA by multivariate analysis. Donor-type plasma exchange and anti-CD20 monoclonal antibody is an effective approach for the treatment of PRCA. PRCA could be prevented by plasma exchange prior to transplantation.

[Sickle cell anemia and transfusion safety in Bamako, Mali. Seroprevalence of HIV, HBV and HCV infections and alloimmunization belonged to Rh and Kell systems in sickle cell anemia patients]

Red cell transfusion is one of the main treatments in sickle cell disease. However there are potential risks of blood transfusions. In order to propose strategies to improve blood safety in sickle cell disease in Mali, we conducted a prospective study of 133 patients with sickle cell anemia recruited at the sickle cell disease research and control center of Bamako, November 2010 to October 2011. The study aimed to determine the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infections by serum screening and the frequency of red cell alloimmunization before and after blood transfusion. The diagnosis of sickle cell syndrome was made by HPLC, the detection of markers of viral infection was performed by ELISA, and the diagnosis of alloimmunization was conducted by the Indirect Coombs test. Prevalence of viral infections observed at the time of enrolment of patients in the study was 1%, 3% and 1% respectively for HIV, HBV and HCV. Three cases of seroconversion after blood transfusion were detected, including one for HIV, one for HBV and one another for HCV in sickle cell anemia patients. All these patients had received blood from occasional donors. The red cell alloimmunization was observed in 4.4% of patients. All antibodies belonged to Rh system only. Blood transfusion safety in sickle cell anemia patients in Mali should be improved by the introduction of at least the technique for detecting the viral genome in the panel of screening tests and a policy of transfusions of blood units only from regular blood donors.

Transfusion therapy for sickle cell disease: a balancing act

Transfusion therapy is a key intervention in decreasing morbidity and mortality in patients with sickle cell disease (SCD). Current indications for acute and chronic transfusion therapy have significantly increased the number of RBC units transfused to patients with SCD worldwide. This review summarizes transfusion management for the treatment or prevention of neurologic and perioperative complications, acute chest syndrome, and acute anemia associated with SCD. Despite the recognized benefits of transfusion therapy, it is not without the risks of iron overload, alloimmunization, and delayed hemolytic transfusion reactions. Transfusional iron overload management includes automated RBC exchange, noninvasive imaging to monitor iron burden, and iron chelation with parenteral or oral agents. Although limited and extended RBC antigen matching reduces antibody formation, the prevalence of RBC alloimmunization in patients with SCD remains high. Recent studies demonstrate that RH genetic diversity in patients with SCD contributes to Rh alloimmunization, suggesting that even more refined RBC matching strategies are needed. Advances in molecular blood group typing offer new opportunities to improve RBC matching of donors and recipients and can be of particular benefit to patients with SCD.

Immediate adverse reactions to platelet transfusions: whole blood derived versus apheresis platelets

The transfusion of whole blood derived platelets (WBDPs) or apheresis platelets (APs) is standard support for cancer patients. However, disputes remain about which type of platelets are ideal in terms of efficacy, cost, and the risk of adverse reactions. This cross sectional study included 141 cancer patients who underwent chemotherapy or hematopoietic progenitor cell transplantation and received platelet transfusions at The University of Texas M.D. Anderson Cancer Center between 2002 and 2003 were retrospectively evaluated. A total of 141 patients who did not differ significantly in terms of age or sex had a reaction to transfusions (WBDPs, n=123; APs, n=18), for a frequency of 0.66% in patients who received WBDPs and 0.45% in patients who received APs, but this difference was not statistically significant (p=0.13). More WBDP-related reactions occurred in patients transfused with older platelets (>2 days old) than in patients transfused with fresh platelets, but the difference compared with AP-associated reactions was not statistically significant. However, the rate of reactions to WBDP may increase if WBDPs are stored for a prolonged time (>2 days). Until evidence becomes available that clearly refutes this; the more fresh platelets as possible may be used.

Early death and late morbidity after blood transfusion of injured children: a pilot study

BACKGROUND/PURPOSE

Early postinjury death after packed red blood cell (pRBC) transfusion is attributed to uncontrolled hemorrhage and coagulopathy. The adverse immunomodulatory effects of blood transfusion are implicated in subsequent morbidity. We hypothesized that injured children requiring pRBC transfusion demonstrate patterns in outcome similar to those observed in adults.

METHODS

Our prospectively collected trauma registry was queried for demographics, treatment, and outcome (2006-2009). Outcomes of children who received pRBC transfusion were compared with those of age- and Injury Severity Score (ISS)-matched children who did not receive pRBC transfusion by both univariate and multivariable analysis.

RESULTS

Eight percent (43/512) of injured children received a pRBC transfusion: 20 early and 23 late. The likelihood of pRBC transfusion increased with increasing ISS (ISS <15, 2%; ISS 16-25, 17%; ISS >25, 72%). One-half of injured children who received an early pRBC transfusion died; however, most deaths were because of central nervous system injury. Both ventilator and intensive care unit days were increased in children who received pRBC transfusion as compared with those who did not.

CONCLUSION

Early pRBC transfusion is associated with a high mortality in children. Late blood transfusion is associated with worse outcomes, although this relationship may not be causal. This pilot study provides evidence of an association between pRBC transfusion, morbidity, and mortality among injured children that warrants refinement in larger, prospective investigations.

Transfusion practices for patients with sickle cell disease at major academic medical centers participating in the Atlanta Sickle Cell Consortium

The Atlanta Sickle Cell Consortium represents more than 2600 pediatric and adult patients with sickle cell disease (SCD) in the metropolitan Atlanta, Georgia, area receiving care at four major locations, each providing comprehensive care 24 hours a day, 7 days a week. Both transfusion services that support these sites use two levels of prospective phenotype matching to decrease the rates of alloimmunization. Although exact rates are unknown and are currently under investigation, alloimmunization occurs infrequently with the exception of chronically transfused SCD patients, who represent the minority of active SCD patients. With increasing availability, red blood cell genotyping will be used in the near future both for determination of predicted patient phenotypes and for provision of genotypically matched donor units.

Directed blood donor program decreases donor exposure for children with sickle cell disease requiring chronic transfusion

In children with sickle cell disease (SCD), primary and secondary prevention of strokes require indefinite regular blood transfusion therapy. The risks associated with repeated transfusions include alloimmunization and increased donor exposure. The Charles Drew Program is a directed blood donor program designed to lower donor exposure, decreasing the associated complications of transfusion; however, no evidence exists demonstrating the magnitude of the benefit to the recipient. Further, the use of extended red blood cell (RBC) antigen matching for C, E, and K has been well documented in a clinical trial setting but not extensively evaluated in a standard care setting. The goal of this study is to assess the effectiveness in reducing alloimmunization when matching for C, E, and K and the magnitude of the decrease in donor exposure in a directed blood donor program. The rate of alloimmunization and reduction of donor exposure were determined during the course of 1 year in a cohort of children with SCD who received regular directed donor blood transfusions. A total of 24 recipients were in the program, 16 females and 8 males, 4 to 20 years of age. During 2008, alloimmunization was 0 percent and donor exposure was reduced by 20 percent, compared with usual care. Extended RBC antigen matching has the same benefit as in a clinical trial setting for patients with SCD receiving blood transfusion therapy. Despite significant effort, we only achieved a modest decrease in donor exposure and cannot determine the immediate benefit of a directed blood donor program.

[Preventive measures against transfusion-associated complications and side effects]

The current efforts and strategies have greatly helped reduce transfusion-associated risks. Indeed, the risk of being infected by a contaminated blood unit today is lower than that thirty years ago. This improvement is due to the introduction of nucleic acid testing (NAT). Compatibility testing is designed to ensure that the patient receives the intended units of red cell concentrate (RCC) and that transfusion will be effective with minimum risk of adverse reactions. The process includes ABO and Rh typing of patients, testing recipient serum for clinically important alloantibodies, and crossmatching donor red cells with recipient serum by a technique that detects serological incompatibility.

Blood transfusions. 2: Signs and symptoms of acute reactions

This two-part unit focuses on monitoring patients who have blood transfusions. The first part emphasised the importance of visual observations and monitoring patients' vital signs to ensure rapid action should there be any adverse effects. This second part describes the physiology behind the signs and symptoms of a blood transfusion reaction.

Overt immediate hemolytic transfusion reaction attributable to anti-Wr(a)

Wr(a) is a low-prevalence antigen. Anti-Wr(a) is a relatively common antibody present in approximately 1 in 100 healthy blood donors. Anti-Wr(a) is reported to cause different degrees of hemolysis in transfusion and in HDN, ranging from benign to severe. This report describes an acute overt hemolytic transfusion reaction in a patient whose serum contained anti-Wr(a) and who received a Wr(a+) RBC component.

Hemolytic Transfusion Reaction After Preoperative Prophylactic Blood Transfusion for Sickle Cell Disease in Pregnancy

BACKGROUND

Preoperative transfusions are frequently given to prevent morbidity in nonpregnant patients with sickle cell disease. We describe a case of a life-threatening delayed hemolytic transfusion reaction with hyperhemolysis syndrome in pregnancy.

CASE

A multigravida with sickle cell disease underwent prophylactic blood transfusion before repeat cesarean delivery. Her immediate postpartum course was uneventful, but on postoperative day number 6 she presented in grave condition with what was thought initially to be an infection versus crisis. Delayed hemolytic transfusion reaction with hyperhemolysis was ultimately diagnosed.

CONCLUSION

In the gravida with sickle cell disease and known multiple red cell antibodies, blood transfusion may incur a higher risk for delayed transfusion reaction, hyperhemolysis syndrome, and possible death. Blood transfusion should be used cautiously in these patients.

Frequencies of blood type A, B and AB in non-pedigree domestic cats in Turkey

OBJECTIVES

To determine the distribution of blood types and to estimate the proportion of matings at risk for neonatal isoerythrolysis in non-pedigree domestic cats.

METHODS

The present survey determined the frequency of blood types in 301 cats from four distinct regions of Turkey. Ethylenediaminetetraacetic acid-anticoagulated blood samples were typed by simple tube and slide agglutination assays. Serum obtained from type B cats and an anti-B solution, prepared with Triticum vulgaris, were used to determine type A and type B blood, respectively.

RESULTS

Of the 301 cats typed, 220 had type A blood, 74 had type B and seven had type AB. There was a significant difference (P<0.01) between the locations of the cats, with fewer type B cats in the eastern than in the western parts of Turkey. Risk for the development of neonatal isoerythrolysis due to A-B mismatch was estimated to be 18.6 per cent.

CLINICAL SIGNIFICANCE

The overall type B frequency in Turkish domestic cats is high. Thus, untyped transfusions in these cats carry a high risk of life-threatening acute haemolytic transfusion reactions and neonatal isoerythrolysis. It is therefore strongly recommended that blood typing be performed before breeding or transfusing in order to minimise blood type incompatibility risks.

[Severe bleeding in a patient with anti-c alloantibodies and a rare Rhesus phenotype treated with compatible erythrocyte concentrate from the blood bank of the Council of Europe]

An 84-year-old women had repeated gastrointestinal bleeding from a Dieulafoy lesion, i.e. a gastric or duodenal ulcer containing an aberrant artery. Her blood group was AB-D negative; her Rhesus phenotype was CCdee. In addition, antibody screening revealed anti-c alloantibodies as the result of a previous transfusion. Donors negative for D and c are very rare in Caucasian populations. Compatible red cell concentrates are available only from the European Bank of Frozen Blood of the Council of Europe, located at Sanquin in Amsterdam, Tthe Netherlands. The patient could be saved by requesting compatible erythrocyte concentrate from this blood bank. Severe blood loss poses a serious challenge in patients who are positive for alloantibodies against blood group antigens with a high frequency in the population, and in patients who are themselves negative for such antigens. The presence of alloantibodies is often the result of previous blood transfusions. In view of the large number of antigens on erythrocytes, one should therefore be conservative as to blood transfusion in order to prevent alloantibody formation.

Transfusion errors in the Thai Anesthesia Incidents Study (THAI Study): three cases

Of 163,403 recorded cases of anesthesia in the Thai Anesthesia Incidents Study (THAI Study), transfusion errors occurred thrice. Case #1: a 68-year-old male, blood group A, undergoing hepatectomy, received two units of PRC and four units of FFP (all units were group A), but two of the FFP units were given to the wrong patient because the caregiver did not check the patient-identification on all of the blood bags. Case #2: a 42-year-old female, blood group A, undergoing emergency exploratory laparotomy, received 250 mL of group B-blood. Skin rashes, a clue for diagnosis of transfusion error were observed in the postoperative period. The error occurred because the caregiver did not check the patient-identification before starting the transfusion. Case #3: a 42-year-old female, blood group O, undergoing hysterectomy, received 430 mL of group AB-blood. More blood was requested in the ICU and it was discovered that the new bag was group O instead of AB. Mislabeling of the blood sample at the first blood request accounted for the error even though blood group O was recorded on the patient's OPD chart. The first two patients developed minor adverse reactions (grade 1) whereas the third developed a severe reaction (grade 3). All of the patients responded well to treatments. Accordingly, the system for preventing transfusion errors has been improved at both hospitals.

Transfusions de concentrés plaquettaires Rhésus incompatible au CHU de Rouen : pratiques et conséquences

INTRODUCTION

Guidelines for distribution and use of blood products have been established for both blood transfusion institution and hospitals, in particular for the use of Rh (D)-incompatible platelet concentrates. The aim of this study was to evaluate: 1) the rate of attribution for the Rh (D)-incompatible platelets concentrates, 2) the immunisation prophylaxis practices, 3) the immunological consequences using short and medium term follow-up of transfused patients.

METHODS

Patients with Rh (D)-incompatible platelets concentrate administered during the year 2003 at Rouen University Hospital were retrospectively selected. Patients on transfusion were described. The relationship of various factors with the injection as well as the appearance of allo-immunization was statistically tested.

RESULTS

During a year, 280 Rh (D)-incompatible platelets concentrates were administered to 67 patients. Immunisation prophylaxis by injection of Ig anti-D was not systematically performed. Four immunizations in the Rhesus group system were identified: 2 against D antigen (Ag), 1 against E Ag and 1 against C Ag. Immunisations against D Ag occurred for two younger women considered as immunodeficient. Immunization prophylaxis was more frequent in poly-transfused patients. However no difference was observed for the other factors.

CONCLUSION

Compatibility concerning Rhesus (D) is not always possible. The immunization against red cells persists, in particular against the antigens of the Rhesus group system and moreover for the immunodeficient patients. Recommendations for immunization prophylaxis by injection of specific anti-D immune-globulin (Ig) could be reconsidered.

A comprehensive analysis of DEL types: partial DEL individuals are prone to anti-D alloimmunization

BACKGROUND

The D antigen of the polymorphic Rh blood group system is of particular clinical importance regarding transfusion- and pregnancy-induced alloimmunization. Different RhD variants with specific clinical implications have been characterized. The least expressed D variants collectively called DEL are serologically detectable only by adsorption-elution techniques, with so far only poorly defined antigenic properties.

STUDY DESIGN AND METHODS

A comprehensive immunohematologic analysis of five of the six currently known DEL genotypes was performed. DEL phenotypes associated with the RHD(M295I), RHD(IVS3+1g>a), RHD(K409K), RHD(X418L), or RHD(IVS5-38del4) allele were characterized with extended serology and flow cytometry.

RESULTS

Epitope mapping with adsorption-elution revealed a prominent D epitope loss in the RHD(IVS3+1g>a)-associated DEL phenotype, whereas in the other four DEL types no signs of qualitative D antigen alteration were detected. The observation of alloanti-D in two RHD(IVS3+1g>a) cases confirmed the partial nature of this DEL phenotype. The RHD(M295I) phenotype exhibited the highest D antigen expression among all investigated DEL types, as determined by a semiquantitative adsorption-elution approach and flow cytometry.

CONCLUSION

In conclusion, evidence is provided that different DEL genotypes code either for partial or complete D antigen expression and that this finding is clinically relevant.

Partial D, weak D types, and novel RHD alleles among 33,864 multiethnic patients: implications for anti-D alloimmunization and prevention

BACKGROUND

The D antigen includes category D, partial D, and weak D types, which are important because anti-D alloimmunization can occur in some but not all persons that express a variant RHD allele. At present, there is little prospective information on the prevalence of D variants among obstetric patients and potential transfusion recipients.

STUDY DESIGN AND METHODS

The RHD alleles were prospectively examined in a large patient population identified on the basis of a difference in anti-D reactivity between two reagents.

RESULTS

Fifty-five discrepancies (0.96% of D-) were noted among 33,864 ethnically diverse patients over 18 months, of which 54 represented mutated RHD alleles. Seven obstetric patients were assigned D- status based on serology; only 1 patient had a partial RHD allele. Ten of 25 (36%) obstetric patients and 4 of 6 (67%) female potential transfusion recipients of childbearing age or younger were assigned D+ status, and they expressed a D variant known to permit anti-D alloimmunization. In total 20 RHD alleles were identified including category, DVa or DVa-like alleles (n = 7), DAR (n = 8), and four novel RHD alleles including two new DAU alleles.

CONCLUSION

Given the complexity of D antigen expression, it is concluded that some clinically important D variants identified by standard serologic analysis phenotype as D+ and are potentially at risk for the development of anti-D.

Alloimmunization to red blood cell antigens after universal leucodepletion. A regional multicentre retrospective study

Leucodepletion has been shown to reduce human leucocyte antigen immunization, but studies on the effect of leucodepletion on red cell alloimmunization reported discordant results. We conducted a retrospective multicentre study to determine whether prestorage filter leucodepletion alters the development of clinically significant red blood cell alloimmunization against the Rhesus, Kell, Duffy, Kidd and MSs blood group systems. Two periods were investigated, 2 years before and 2 years after universal leucodepletion. Comparisons were made between the transfused patient cohorts. To control for changes not related to leucoreduction, we compared antibody incidence with antibody prevalence in the two study periods. Newly detected antibodies (n = 4770) were found in 4115 patients from 19 participating hospitals. Of these, 857 antibodies in 659 patients were because of transfusions given in the study periods. The immunization risk was 0.13% for both periods. No differences were found regarding incidence of new antibodies, nor for patients regarding age, sex, previous antibodies, multiple antibodies, additional antibodies, number of transfusions, transfusions episodes and days from transfusion to date of immunization. In conclusion, compared with buffy-coat leucoreduction, universal prestorage filter leucodepletion did not alter the development of clinically significant red blood cell alloimmunization.

Levels of Anti-A/B Antibodies After ABO-Incompatible Hematopoietic Stem Cell Transplantation

In contrast to solid organ transplantation, ABO incompatibility is generally not associated with survival differences in hematopoietic stem cell transplantation. Therefore, patients receiving ABO-incompatible stem cell transplantation can be analyzed to study the mechanism of tolerance induction after antigen-mismatched transplantation. The goal of this study was to analyze the levels of anti-A/B antibodies after ABO-incompatible transplantation. Host-derived antidonor antibodies disappeared rapidly after transplantation and did not reappear in the further posttransplant course. Donor-derived antihost antibodies did not significantly increase and compatible anti-A/B antibodies remained positive after hematopoietic stem cell transplantation. Thus, there is no evidence for stimulation of donor B lymphocytes to produce antirecipient antibodies suggesting a potential B cell tolerance.

How safe is transfusion of uncross-matched group-specific blood?

OBJECTIVE

Uncross-matched blood either group specific or Group O is advocated in patients with exsanguinating haemorrhage when cross-matched blood cannot be made available rapidly. The risk of using uncross-matched blood is not known clearly. The purpose of this study is to attempt to quantify the risk of major transfusion reactions resulting from the use of uncross-matched group specific blood.

METHOD

The cross-matching record of Patan hospital for the period of two years was analysed looking at the number of units that had major or minor incompatibility among all the cross-matching done during this period.

RESULT

A total of 6027 units were cross-matched in two years. Only one unit of blood was found to have both major and minor incompatibility. All other units of blood taken out from the freeze for the purpose of cross-matching matched the patients blood. This puts the risk of having major transfusion reaction from incompatible blood when using uncross-matched group-specific blood at 1 in 6000.

CONCLUSION

Using uncross-matched group specific blood in patients with severe haemorrhage, when delay in transfusion can put life at risk, is justifiable and needs to be encouraged.

Case report: immune anti-D stimulated by transfusion of fresh frozen plasma

FFP has occasionally been reported to generate an immune response to RBC antigens (e.g., anti-D and anti-Fya). The Council of Europe requires that each unit of FFP have less than 6 x 10(9)/L RBCs. However, there is considerable variation internationally in the method of production and the level and assessment of RBC contamination of FFP. This study reports the case of a 63-year-old group B, D- man who received multiple transfusions of D- blood products over a 4-month period. Seven months later the patient's antibody screen remained negative and he was transfused with seven units of D- RBCs and six units of FFP, four of which were D+. Two months later anti-D, -E, and -K were detected in his plasma. Although the anti-E and anti-K could have resulted from transfusion of antigen-positive RBCs, the anti-D could have resulted only from transfusion of the D+ FFP. The D status of FFP is currently not considered when selecting products for transfusion even though the D antigen is highly immunogenic and the level of RBC contamination of FFP is not always known. This case highlights that transfusion of FFP is a stimulus for RBC antibodies and that when a patient has had a recent transfusion of FFP, consideration should be given to obtaining a sample for pretransfusion testing within 3 days before a scheduled RBC transfusion. In addition, the D status of FFP should be considered before administering FFP to premenopausal D- women.

[Blood transfusion safety: current progress]

For the past ten years, a real improvement in knowledge and methods concerning blood transfusion safety has been made. In this observation, concerning a polytraumatism patient who received massive blood transfusion with no immunologic nor infectious complications occurring one year later, brings evidence of real progress on blood transfusion safety for improvement in short and long term prognosis for polytransfused patients.

Factors influencing moderate to severe reactions to PLT transfusions: experience of the TRAP multicenter clinical trial

BACKGROUND

During the Trial to Reduce Alloimmunization to Platelets (TRAP Trial), data were prospectively collected for 8769 PLT transfusions regarding the frequency of moderate to severe PLT transfusion reactions.

STUDY DESIGN AND METHODS

At seven centers, 598 patients were randomly assigned to receive unmodified pooled random-donor PLT concentrates (PCs), UV-B-irradiated PCs, filtered PCs, or filtered random-donor apheresis PLTs.

RESULTS

Moderate to severe transfusion reactions were an increase in temperature of at least 2 degrees C, chills with rigors, extensive urticaria, dyspnea, cyanosis, or bronchospasm. These reactions occurred with 2.2 percent of the transfusions in 22 percent of the patients. Transfusion reactions were associated with WBC counts of more than 5 x 10(6) per transfusion (p = 0.002) and transfusions stored for more than 48 hours (p = 0.02). PLT counts before transfusion were significantly lower for transfusions associated with reactions (p = 0.005). Neither UV-B irradiation nor apheresis PLTs independently influenced reaction rates. The PLT increment at 1 hour after transfusion was lower for transfusions associated with reactions (p = 0.004), and the frequency of reactions was higher in PLT refractory patients (p < 0.001).

CONCLUSIONS

The provision of either fresh and/or WBC-reduced PLTs may decrease the frequency of PLT transfusion reactions and improve PLT transfusion efficacy.

Delayed hemolytic transfusion reaction/hyperhemolysis syndrome in children with sickle cell disease

OBJECTIVE

Alloimmunization in patients with sickle cell disease (SCD) has a reported incidence of 5% to 36%. One complication of alloimmunization is delayed hemolytic transfusion reaction/hyperhemolysis (DHTR/H) syndrome, which has a reported incidence of 11%. In patients with SCD, clinical findings in DHTR/H syndrome occur approximately 1 week after the red blood cell (RBC) transfusion and include the onset of increased hemolysis associated with pain and profound anemia. The hemoglobin (Hb) often drops below pretransfusion levels. In many reported adult cases, the direct antiglobulin test (DAT) remains negative and no new alloantibody is detected as the cause for these transfusion reactions. To date, few pediatric cases have been reported with this phenomenon. The objective of this study was to describe the clinical and laboratory findings of a case series in children who had SCD and experienced a DHTR/H syndrome at our institution.

METHODS

An 11-year retrospective chart review of patients with discharge diagnosis of SCD and transfusion reaction was performed. DHTR/H syndrome was defined as the abrupt onset of signs and symptoms of accelerated hemolysis evidenced by an unexplained fall in Hb, elevated lactic dehydrogenase, elevated bilirubin above baseline, and hemoglobinuria, all occurring between 4 and 10 days after an RBC transfusion. Patient characteristics, time from transfusion, symptoms, reported DAT, new autoantibody or alloantibody formation, laboratory abnormalities, and complications were recorded. Patients with acute transfusion reactions were excluded.

RESULTS

We encountered 7 patients who developed 9 episodes of DHTR/H syndrome occurring 6 to 10 days after RBC transfusion. Each presented with fever and hemoglobinuria. All but 1 patient experienced pain initially ascribed to vaso-occlusive crisis. The DAT was positive in only 2 of the 9 episodes. The presenting Hb was lower than pretransfusion levels in 8 of the 9 events. Severe complications were observed after the onset of DHTR/H: acute chest syndrome, n = 3; pancreatitis, n = 1; congestive heart failure, n = 1; and acute renal failure, n = 1.

CONCLUSIONS

DHTR/H syndrome occurs in pediatric SCD patients, typically 1 week posttransfusion, and presents with back, leg, or abdominal pain; fever; and hemoglobinuria that may mimic pain crisis. Hb is often lower than it was at the time of original transfusion, suggesting the hemolysis of the patient's own RBCs in addition to hemolysis of the transfused RBCs; a negative DAT and reticulocytopenia are often present. Severe complications including acute chest syndrome, congestive heart failure, pancreatitis, and acute renal failure were associated with DHTR/H syndrome in our patients. DHTR/H in the pediatric sickle cell population is a serious and potentially life-threatening complication of RBC transfusion. It is important to avoid additional transfusions in these patients, if possible, because these may exacerbate the hemolysis and worsen the degree of anemia. DHTR/H syndrome must be included in the differential of a patient who has SCD and vaso-occlusive crisis who has recently had a transfusion.

[Examination for prevent of blood transfusion errors]

Human error has identified as a major source of ABO incompatibility-related transfusion fatalities. Frequency of ABO-incompatible transfusion has been reported to range from 2.5 to 253 per 100,000 transfusion units. Transfusion error has developed various occasions, for example, wrong specimen and patients, specimen exchange and mistake of ABO compatibility test. In laboratory examination, many errors were occurred during night shift, because it was necessary to established the examination system. We discussed about examination for prevent of blood transfusion errors.

[Present state of transfusion errors]

Most serious transfusion error is ABO-incompatible transfusion. The Japanese Society of Blood Transfusion reported the results of the National Survey on the present state of ABO-incompatible blood transfusion in Japan. The targets of the survey were 777 hospitals with more than 300 beds, which have transfused more than 3,000 units of blood products per year. The answer could be obtained from 578(74%) hospitals among them. The questionnaire focused on the presence or absence of ABO-mismatched transfusion between January 1995 and December 1999. 115 hospitals(20%) have experienced ABO-mismatched transfusion in the period of the study. The frequency of ABO-mismatched transfusion increased with increasing the number of beds and the units of transfused blood. The ABO-mismatched transfusions were due to clerical or technical errors. The main causes of errors were misidentification of blood bags(42.8%), incorrect blood typing(15.1%) and failure to identify patient (11.5%). Incorrect blood typing errors were performed in 25 cases, and were caused by doctors in 17 cases, others by laboratory technicians. Majority of incorrect blood typing occurred during holidays or night shifts, and in emergency.