Characterization of three novel monoclonal anti-OKa

Anti-Ok(a) was first described by Morel and Hamilton in 1979. The Ok(a) antigen has a very high incidence, and only eight probands that are Ok(a-) have been found; all are of Japanese heritage. In this study,we describe the generation and characterization of three novel monoclonal antibodies (Mabs), MIMA-25, MIMA-144, and MIMA-149. The reactivity of these three Mabs was compared with the original human polyclonal anti-Ok(a). Mice were immunized with transfected HEK cells to induce an immune response, and the spleen B lymphocytes were fused with mouse myeloma X63-Ag8.653 cells to form antibody-secreting hybridomas. The resulting Mabs were tested serologically, by flow cytometry, and by immunoblotting. The specificity of each antibody was determined after excluding specificities to common antigens in the Rh, Kell, Duffy, Kidd, MNS, Lewis, Lutheran, P1, Colton, Diego, Xga, and Dombrock blood group systems. In each case only the Ok(a-)RBC sample was nonreactive. The Mabs and the original human anti-Ok(a) each have a unique pattern of reactivity when tested with enzyme-treated cells; however, none were reactive by immunoblotting. We have generated three novel anti-Ok(a) Mabs: MIMA-144 is an indirectly agglutinating IgG2b antibody, and MIMA-25 and MIMA-149 are directly agglutinating antibodies (IgM and IgA, respectively), underscoring their usefulness as typing reagents for the clinical laboratory.

A simple screening assay for the most common JK*0 alleles revealed compound heterozygosity in Jk(a-b-) probands from Guam

The Jk(a-b-) phenotype results from alterations in the JK gene and is characterized by absence of the RBC urea transporter in the cell membrane. The frequency of Jk(a-b-) varies among populations,but this phenotype is most commonly found in people of Polynesian and Finnish descent. Although rare, Jk(a-b-) individuals present a clinical challenge because anti-Jk3 is produced readily in response to transfusion and pregnancy, and Jk(a-b-) blood is not routinely available. Identification of Jk(a-b-) patients and donors is most often performed serologically. However, ten JK*0 alleles have been identified, and this information can be used in DNA-based typing. We selected five JK*0 alleles that had been encountered by our reference laboratory in two or more samples from unrelated individuals and designed an allele-specific primer PCR assay for use as an initial screening tool. After in-house validation,we tested genomic DNA from a family: a mother and her two sons referred to us for genetic investigation of their Jk(a-b-)phenotypes. Two different nucleotide substitutions, -1g>a in intron 5 (IVS5) and 956C>T in exon 10, originally associated with Polynesian and Indian/African populations respectively, were identified in the family. The mother and one son were compound heterozygotes, and the second son was homozygous for IVS5-1g>a. We conclude that the effort to design and validate such a screening assay was cost-efficient when compared with DNA sequencing costs. Furthermore, selection of the more common JK*0 mutations was a practical approach that resulted in rapid identification of the genetic bases behind the Jk(a-b-) phenotypes in this unusual family. Although an obvious target for eventual inclusion into high-throughput genotyping platforms for clinical diagnostic services, current systems are very limited. Our approach provides a simple and inexpensive method for the identification of these rare alleles.

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.

Antibody screening in repeatedly transfused patients

The purpose of pretransfusion compatibility testing is to prevent immune mediated hemolytic transfusion reactions. Our study aimed to evaluate the gel test for detection of clinically significant antibodies in repeatedly transfused patients. We investigated 200 thalassemic patients in whom, blood group, Rh-D, Rh phenotype determination, antibody screening and identification were done using an ID Microtyping System. Red cell alloantibodies were detected in 21 patients (10.5%). Among these patients, Anti-E was detected in 5 (23.8%), anti-D in 4 (19%), anti-K in 4 (19%), anti-e in 3 (14.3%) and each of anti-Fy(a), anti-Js(a), anti-Lu(a), anti-N and anti-s in one patient (4.8%). Anti-E showed the highest frequency in the 21 positive cases that developed clinically significant antibodies. The study revealed statistically significant correlation between development of transfusion reactions, frequency of blood transfusion and the duration of blood transfusion with the incidence of development of clinically significant alloantibodies. It is concluded that the gel test is an easy, quick and reliable method for detecting clinically significant antibodies. Antibody screening and identification is recommended prior to transfusion to detect if there is blood group incompatibility other than the ABO and Rh.

Severe HPA-15b related neonatal alloimmune thrombocytopenia

The HPA-15 platelet (PLT) group was recently described. Severe neonatal thrombocytopenia due to alloimmunization by HPA-15b has very rarely been observed. A 22-year-old mother, gravida 1/para 1, gave birth to a male infant who presented with a severe thrombocytopenia, the PLT count recorded to be 3 x10(9)/L. A few hours after birth, he developed purpura with extensive haematomas but without visceral or intracranial haemorrhage (ICH). Two PLT transfusions were given including one using maternal PLTs. The infant's PLT count was 267 x 10(9)/L on day 6. The maternal platelet group was HPA-15a/a and her infant was HPA-15a/b. Anti-HPA-15b antibodies was found in maternal serum.

CONCLUSION

HPA-15b maternal alloimmunization may induce severe neonatal thrombocytopenia. In order to establish the frequency of neonatal alloimmune thrombocytopenia (NAIT) due to anti-HPA-15b antibodies, an improved detection method is necessary.

Clinical characteristics of thrombotic microangiopathy following ABO incompatible living donor liver transplantation

Thrombotic microangiopathy (TMA) may develop after living donor liver transplantation (LDLT), but the mechanism is not fully understood. We retrospectively analyzed all patients undergoing LDLT at our center, including TMA patients, to elucidate the clinical characteristics and presentation and to determine which patients have a higher risk of occurrence of TMA. In all, 57 adult patients were reviewed after LDLT at our institution. TMA was diagnosed by sudden and severe thrombocytopenia, followed by hemolytic anemia with fractionated erythrocytes in the blood smear. Clinical features were compared between the TMA group and the non-TMA group. Of the 57 patients, 4 were diagnosed with posttransplantation TMA. ABO blood group (ABO)-incompatibility, cyclophosphamide (CPA), and recipient blood group (type O) were closely correlated with the occurrence of TMA. Thrombocytopenia appeared 1 to 5 days before hemolytic anemia. Coagulative function markers stayed at the same level after TMA, while marked elevation was shown in fibrinolytic function markers such as plasminogen activator inhibitor type 1 (PAI-1). TMA occurred at a higher prevalence in ABO-incompatible graft recipients. Additional factors associated with ABO-incompatible transplantation, such as an overdose of immunosuppressants, may affect the likelihood of TMA. Sudden and severe thrombocytopenia presented before hemolytic anemia and the serum levels of PAI-1 correlated well with the clinical course of TMA. In conclusion, early recognition of thrombocytopenia and elevation of PAI-1 is crucial to diagnose TMA especially in ABO-incompatible LDLT.

Errors in ABO labeling of deceased donor kidneys: case reports and approach to ensuring patient safety

Patient safety in transplantation depends on accurate testing, transcription and transmission of the ABO types of the donor and recipient. Similar to 'near-miss' transfusion labeling errors, three cases of mislabeled ABO types on deceased donor kidney containers were recognized through a pretransplant verification process. Six steps to confirming the organ and ABO identification were developed to ensure safety of the patient and prevent liability for the transplant team and facility. In each case, rapid recognition and documentation of the error source, on site confirmation of the ABO type of the accompanying blood specimen, and full disclosure to the patient and family permitted safe transplantation and avoided the need to pursue a more conservative course that would have required discarding the organs. We advocate following these measures in determining whether to persevere with transplantation of a mislabeled organ.

A confusion in antibody identification: anti-D production after anti-hrB

It is well known that certain combinations of alloantibodies are frequently found together. Patients with sickle cell disease (SCD) are mostly ofAfrican ancestry,and they may make anti-hrB. A transfusion of hrB- blood is often achieved by using e- (R2R2) RBCs; it is generally believed that hrB- patients readily make anti-E or a"broad-spectrum" anti-Rh34 (-HrB). We describe two multiply transfused D+ patients with SCD and a history of anti-hrB who subsequently produced anti- D. This raises the question whether anti-hrB together with anti-D is a more common antibody combination than anti-hrB with anti-E or anti-Rh34.

[A case of Edwards' syndrome in pregnancy complicated by serologic incompatibility and preeclampsia]

A case of Edwards' syndrome (trisomy 18) diagnosed in the third pregnancy trimester is described. The diagnosis was based on sonographic examination and cytogenetic amniocentesis. Lethal genetic fetal malformation determined the medical indication to preterm delivery. Additionally, serologic incompatibility during pregnancy was observed, as well as pregnancy induced hypertension turning into preeclampsia after the labour action was evoked. A caesarean section due to obstetric indications was done. Phenotype and lethal congenital malformations in the newborn have confirmed of the chromosome aberration prenatally diagnosed.

Anti-KEL7 (anti-Js(b)) alloimmunization diagnostic supported by molecular KEL*6,7 typing in a pregnant woman with previous intrauterine deaths

Anti-KEL7 (anti-Js(b)) is a rare antibody that has been related to haemolytic transfusion reactions and HDN. We report a case of anti-KEL7 alloimmunization detected in a pregnant woman who had an obstetric previous history of four miscarriages and one stillborn. Employing classical immunohematological techniques, we studied the propositus and her available relatives. Due to the unavailability of commercial anti-KEL6 and anti-KEL7 reagents, we used a KEL*6,7 genotyping method as an alternative tool to contribute with the identification of the alloantibody origin. The results of KEL genotyping showed that the propositus was KEL*6/6 homozygous, while her second partner was KEL*7/7 homozygous.

Detection of red cell antibodies: comparison of two low ionic strength diluents

Various low ionic strength diluents are used routinely for red cell alloantibody detection in the antiglobulin test to increase the rate of antibody association to antigen, thereby allowing a reduction in the incubation time while achieving optimal agglutination. Two commercial low ionic strength diluents (DiaMed ID-CellStab and Inverclyde LISS) were assessed using the DiaMed-ID LISS Coombs' microtube column system, to assess whether or not the choice of diluent influences red cell antibody detection. Effects of two low ionic strength diluents after 15-min incubation were assessed in 150 samples containing a wide range of typical red cell alloantibodies. Inverclyde LISS gave significantly higher reaction strengths in 25% of samples when compared with the same red cells suspended in ID-CellStab. Variation in reaction strengths ranged from 1+ to 2+, using Inverclyde LISS versus CellStab. Of 131 red cell alloantibodies directed against Rh, Kell, Kidd and Duffy antigens, Inverclyde LISS detected 90% after 15-min incubation, whereas 83% were detected with CellStab. This study suggests that Inverclyde LISS provides better red cell alloantibody detection than does ID-CellStab, and this may be due to the higher ionic strength of ID-CellStab.

Recent developments in fetal nucleic acids in maternal plasma: implications to noninvasive prenatal fetal blood group genotyping

The discovery of circulating cell-free fetal DNA in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. Fetal DNA in maternal plasma has been used for the noninvasive prenatal determination of the RhD status of fetuses carried by RhD-negative pregnant women. In such analysis, the possible need of an internal control for the presence of detectable amounts of fetal DNA in a particular maternal plasma sample has been actively discussed. Recently, the development of a robust method for discriminating single nucleotide differences in plasma DNA using single allele base extension reaction (SABER) followed by matrix-assisted laser-desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) has opened up the possibilities of using a panel of single nucleotide polymorphisms as such a positive control. A second approach is the recent successful development of fetal epigenetic markers which can be developed into universal fetal DNA markers. These developments hold promise to allow the eventual widespread utilization of maternal plasma DNA analysis for the noninvasive prenatal diagnosis of blood group mismatches between the mother and fetus.

Non-invasive antenatal RHD typing

The existence of cell free fetal DNA, derived from apoptotic syncytiotrophoblast, in the maternal circulation has opened new possibilities of non-invasive prenatal diagnosis. Although still some technical problems exists, especially the lack of a generic positive control on the presence of fetal DNA and the aspecific amplification of background maternal DNA, non-invasive prenatal RHD typing has been successfully introduced in several laboratories, especially in Europe. The diagnostic accuracy reaches>99%. In the Netherlands PCR guided administration of antenatal anti-D prophylaxis is cost-effective and nearby. In this review the main characteristics and applications of cell free fetal DNA are discussed, with an emphasis on prenatal RHD genotyping.

Possible insensitivity of the polybrene antibody screen to detect anti-Jka

An acute hemolytic transfusion reaction (AHTR) occurred in a 28-yr-old gravida immediately after transfusion with leukocyte-reduced red cells. The patient gave no history of prior transfusion. Initial serologic testing by the polybrene method was negative for both antibody screening and cross-matching. Further testing by the indirect anti-globulin test (IAT) demonstrated the presence of anti-Jka antibodies. These observations suggest a limitation in polybrene testing for Jka antibodies associated with hemolytic transfusions. Caution is advised when the polybrene test is used as the sole determinant for anti-Jka.

Overcoming Immunologic Incompatibility: Transplanting the Difficult to Transplant Patient

Immunologic incompatibilities between donor and recipient have limited the access to renal transplantation for many patients. Previously the presence of donor-specific alloantibodies directed against donor major histocompatibility complex (MHC) antigens or natural antibodies directed against donor ABO blood group antigens was considered an absolute contraindication to renal transplantation. However, with the current understanding of humoral immune responses, superior immunosuppressive agents, and improved diagnosis and treatment of antibody-mediated rejection, renal transplantation can be safely performed with outstanding results despite the presence of donor-specific antibody. In this review we discuss the biology of antibody-mediated rejection and sensitization. We discuss the diagnostic tests necessary to characterize the type, affinity, and avidity of the donor-directed antibodies. Current methods for performing renal transplants across ABO and human leukocyte antigen (HLA)-sensitized barriers are covered, including the potential morbidities. The rest of the review focuses on advances in managing these antibodies to increase the likelihood of receiving a deceased donor kidney or allow transplantation from a living donor against whom one has a prohibitive antibody.

[The practice guideline 'Blood transfusion' (third integral revision)]

The revised and expanded practice guideline 'Blood transfusion' describes the whole transfusion chain within the hospital for the first time. Despite compatibility tests before transfusion (determination of the ABO and Rhesus blood groups and detection of clinically relevant antibodies (C, c, D, E, e, Fy(a), Fy(b), Jk(a), Jk(b), M, S and s)), transfusion reactions can occur. So that a transfusion reaction can be recognised in time, the patient must be observed intensively for the first 5-10 minutes after the start of any new transfusion and the vital functions must be recorded. In patients with a Hb level of 4-6 mmol/l, the decision whether or not to transfuse should be made dependent on the patient's other characteristics. Thrombocyte transfusion is not indicated in case of thrombopenia due to increased breakdown or pooling. If leukaemia, tumour infiltration or drug toxicity is the underlying cause of thrombopenia, then a platelet count of 10 x 10(9)/l or 20 x 10(9)/l should be the transfusion trigger. Reduction of the number of blood transfusions can be achieved by the administration of epoetin in case of renal insufficiency: transfusion can thus be avoided in more than 70% of the patients concerned. Autotransfusion during surgery with severe blood loss also results in a reduction of the number of allogenic blood transfusions.

[Annual Report 2004 - French National Reference Centre for Rare Blood Groups and Immunohaematology (CNRGS)]

In 2004, the French Reference Centre for Rare Blood Groups and Immunohaematology (CNRGS) developed 7 types of activities: 1) Studies of complex Immunohaematology issues (IH), 2) Studies of rare blood phenotypes, 3) the transfusion of patients showing complex issues, 4) IH reactive control in consistency with the 98/79/CE European Directive, 5) European studies and expertise on reactives and techniques, 6) Biotechnologies applied to blood groups, in particular RH, KEL, FY, JK, DO and CO, 7) Implementation of allo-immunization research programs (cellular immunology and grafting issues). The CNRGS efficiency is based on the 'reference-research' link thanks to the Inserm partnership and direct applications to patients allowing to a better risk management and control.

[Foetomaternal erythrocyte incompatibilities: from immunohaematologic surveillance of pregnant women to haemolytic disease of the newborn]

Despite the generalization of prevention measures against foetomaternal alloimmunization with anti-D immunoprophylaxis since 1970s, retrospectively 30 years later, its complications (new-born child's severe haemolytic disease, foetal death by anemia or nuclear icterus by bilirubin encephalopathy) have not disappeared. At the same time, alloimmunizations against antigens other than D increase with no possible prevention. As part of the set up in France of regional files analysing and making an inventory of serious foetomaternal incompatibilities requiring in utero or neonatal transfusion, we felt the need to synthesize current data, biological profiles (early screening of erythrocytic alloimmunization and its follow up during pregnancy, father's immunohaematologic status, evaluation of in utero immune haemolysis and impact of new non invasive techniques of diagnosis-RH1 foetal genotypage from ADN foetal of RH1--mothers' maternal plasma), clinical and paraclinical data (evaluation of foetal haemolysis by echography, recording of foetal movements and foetal cardiac rhythm), therapeutic indicators (in utero foetal transfusions or exsanguinotransfusions, neo and postnatal transfusions or exsanguinotransfusions, induced premature labour, newborn's intensive continue phototherapy and Rhesus immunoprophylaxis) in order to enable medical and paramedical professionals to carry out the specific supervision of pregnancies with foetomaternal incompatibility, the in utero, neo- and postnatal treatment of child and the efficient therapeutic prevention of anti-D alloimmunization, in a cooperative way.

Analysis of ABO discrepancies occurring in 35 French hospitals

BACKGROUND

The risk of immunohemolytic reaction owing to ABO-mismatched mistransfusion is 100 to 1000 times higher than the risk of viral infection. Like analysis of incident reports, evaluation of near-miss events can provide useful insight into hazardous situations for mis-matched blood transfusion. The aim of this prospective study was to assess the incidence and root causes of all ABO discrepancies, detected by a central hematology laboratory, in blood samples referred from 35 district hospitals.

STUDY DESIGN AND METHODS

ABO discrepancies were detected by comparing either two current blood specimens or a current and historical specimen collected over a 5-year study period. Discrepancies were investigated by retyping new samples, checking sample identification, and reviewing previous hospital records.

RESULTS

A total of 118 ABO discrepancies were discovered in a series of 407,769 tests carried out during the study period. The incidence of ABO discrepancies was 1 per 3,400. This figure was 10 times higher than the incidence of ABO-mismatched transfusions. Most of these ABO discrepancies were due to phlebotomy errors, that is, collection from wrong patient. The second most common cause involved clerical errors during patient registration or identification.

CONCLUSION

ABO discrepancies can result from errors made not only by the medical staff during phlebotomy but also to by the clerical staff during registration and identification. These findings emphasize the need to standardize data transmission between health care personnel.

Evaluation of a modified IAT-gel with polyethylenglycol (PEG) addition method for red blood cell antibody identification

We aimed to evaluate whether a PEG-IAT method, modified for gel technique, could replace the two-stage enzyme method for routine identification of red blood cell (RBC) antibodies.A total of 161 selected patient samples were analyzed with the two-stage enzyme tube technique and the PEG-IAT in gel techniques. In 65 samples, identical antibody results were obtained by the two methods. An additional 28 antibodies were identified by either the PEG-IAT gel method or the enzyme method. Twenty antibodies were identified by the PEG-IAT gel method only (12 Rh antibodies, four anti-Kell, two anti-Fya, two anti-Jka), and eight antibodies by the enzyme method only (four Rh antibodies, one anti-K, one anti-Jka, two anti-Lea). The results in the remaining 68 samples were judged as nonspecific reactions, which were more common when the enzyme method was used. We concluded that the PEG-IAT in gel method identifies more RBC antibodies with less nonspecific reactions than the two-stage enzyme technique. However, no single method detected all clinical significant RBC antibodies.

False positive Kleihauer tests and unnecessary administration of anti-D immunoglobulin

This obstetric case shows two false negative Kleihauer tests and two persistently positive Kleihauer tests leading to unnecessary administration of anti-D immunoglobulin. A diagnosis of hereditary persistence foetal haemoglobin (HPFH) was only confirmed by access to flow cytometry making use of both anti-HbF and anti-D labels. The case highlights the importance of a high index of clinical suspicion for HPFH and the importance of access to flow cytometry estimation of minor RhD red cell populations postnatally in RhD-negative mothers.