Combined liver-kidney transplantation with positive crossmatch: Role of delayed kidney transplantation.

BACKGROUND: Positive crossmatch (XM+) combined liver-kidney transplantation due to preformed donor-specific human leukocyte antigen antibodies has produced mixed results. We sought to understand the role of delayed kidney transplant approach in XM+ combined liver-kidney transplantations. METHODS: XM+ combined liver-kidney transplantations were retrospectively reviewed. T- and B-cell XM, complement-dependent cytotoxic crossmatch, and flow cytometric crossmatch were performed prospectively. RESULTS: Of 183 combined liver-kidney transplantations performed (2002-2019), 114 (62%) were with "delayed" kidney transplant approach and 19 (19 of 183, 10%) were XM+. Of 19 XM+ combined liver-kidney transplantations, kidney transplant was "delayed" in 14 by an average of 47 hours (range 24-64 hours) from liver transplant. There was a significant reduction in both class I (mean pre-liver transplant mean fluorescence intensity (MFI) 26,230 versus mean post-liver transplant and pre-delayed kidney transplant MFI 3,272, P = .01) and total MFI (mean pre-liver transplant MFI 27,233 vs mean post liver transplant and predelayed kidney transplant MFI 11,469, P = .01). However, there was no significant change in the MFI of class II donor-specific antibodies (mean pre-liver transplant MFI 17,899 versus post-liver transplant and pre-delayed kidney transplant MFI 14,341, P = .19). None of XM+ delayed kidney transplants had delayed graft function, and there was no antibody-mediated rejection. One-year patient survival for the XM+ combined liver-kidney transplantation with delayed kidney transplant approach was 92.9%, which is comparable to patient survival of XM- combined liver-kidney transplantation. Whereas patient survival in recipients before "delayed" approach ("simultaneous"; n = 5) was 40% when liver-kidney transplants were performed simultaneously (P = .06). CONCLUSION: In sensitized combined liver-kidney transplantation recipients, the "delayed" kidney transplant approach is associated with a significant reduction in total and class I donor-specific antibodies after liver transplant before kidney transplant, enabling therapeutic interventions such as plasmapheresis, if needed, providing optimal outcomes similar to crossmatch recipients.

Optimizing transfusion management of multiple myeloma patients receiving daratumumab-based regimens.

BACKGROUND: Daratumumab, a human anti-CD38 monoclonal antibody used to treat multiple myeloma, interferes with pretransfusion testing and can mask alloantibodies. Incidence of alloimmunization in patients on daratumumab has not been well characterized, and optimal transfusion guidelines regarding prophylactic antigen matching, accounting for both patient safety and efficiency, have not been well established for these patients. METHODS: Records of patients who received daratumumab between January 1, 2014 and July 2, 2019 were reviewed. Daratumumab interference with pretransfusion testing was managed by testing with reagent red blood cells (RBCs) treated with 0.2 M dithiothreitol. When daratumumab was present during antibody testing, patients were transfused with RBC units prophylactically matched for D, C, c, E, e, and K antigens per hospital policy. RESULTS: Out of 90 patients identified, 52 received a total of 638 RBC transfusions (average of 12.3 units per patient, SD 17.2, range 1-105, median 5 among those transfused). Alloantibodies existing before daratumumab initiation were identified in seven patients. No new alloantibodies were detected in any patients after starting daratumumab treatment. CONCLUSIONS: The incidence of alloimmunization in patients receiving daratumumab is low. Whether this is due to the effect of daratumumab, underlying pathophysiology, or other factors, is unknown. Because these patients require a large number of RBC transfusions overall and have little observed alloimmunization, phenotype matching (beyond RhD) may be unnecessary. Since the use of dithiothreitol cannot rule out the presence of anti-K, we recommend transfusion of ABO-compatible units, prophylactically matched for the D and K antigens only.

HLA class I depletion by citric acid, and irradiation of apheresis platelets for transfusion of refractory patients.

BACKGROUND: Patients can form antibodies to foreign human leukocyte antigen (HLA) Class I antigens after exposure to allogeneic cells. These anti-HLA class I antibodies can bind transfused platelets (PLTs) and mediate their destruction, thus leading to PLT refractoriness. Patients with PLT refractoriness need HLA-matched PLTs, which require expensive HLA typing of donors, antibody analyses of patient sera and/or crossmatching. An alternative approach is to reduce PLT HLA Class I expression using a brief incubation in citric acid on ice at low pH. METHODS AND MATERIALS: Apheresis PLT concentrates were depleted of HLA Class I complexes by 5 minutes incubation in ice-cold citric acid, at pH 3.0. Surface expression of HLA Class I complexes, CD62P, CD63, phosphatidylserine, and complement factor C3c was analyzed by flow cytometry. PLT functionality was tested by thromboelastography (TEG). RESULTS: Acid treatment reduced the expression of HLA Class I complexes by 71% and potential for C3c binding by 11.5-fold compared to untreated PLTs. Acid-treated PLTs were significantly more activated than untreated PLTs, but irrespective of this increase in steady-state activation, CD62P and CD63 were strongly upregulated on both acid-treated and untreated PLTs after stimulation with thrombin receptor agonist peptide. Acid treatment did not induce apoptosis over time. X-ray irradiation did not significantly influence the expression of HLA Class I complexes, CD62P, CD63, and TEG variables on acid treated PLTs. CONCLUSION: The relatively simple acid stripping method can be used with irradiated apheresis PLTs and may prevent transfusion-associated HLA sensitization and overcome PLT refractoriness.

Divergence in phenotyping and genotyping analysis of the Lewis histo-blood group system.

OBJECTIVES: This study evaluated the red blood cell (RBC) Lewis phenotypes by simple haemagglutination technique and molecular genotyping in healthy individuals. BACKGROUND: The expression of Lewis antigen on RBCs is dependent on the interaction of FUT3 and FUT2 genes. Complexity of the genetic control of Lewis antigen expression and the error-prone nature of Lewis phenotyping result in non-genuine RBC Lewis phenotypes, which could be misleading. MATERIALS AND METHODS: ABO blood group and RBC Lewis phenotypes were determined by conventional haemagglutination tube techniques. FUT2 and FUT3 genotypes were analysed by polymerase chain reaction and direct DNA sequencing. The RBC Lewis phenotypes were also inferred from the FUT2 and FUT3 genotyping results. RESULTS: The frequencies of RBC Lewis phenotypes typed by the conventional tube test were Le(a+b-) 19.63%, Le(a-b+) 49.32% and Le(a-b-) 31.05%, whereas the frequencies inferred from the FUT2 and FUT3 genotypes were Le(a+b-) 20.09%, Le(a-b+), 59.82%; Le(a-b-), 17.81%; and Le(a+b+), 5 (2.28%). The Le(a+b+) phenotype was not detected by the tube test, and a significant difference was observed in the frequencies of the determined Le(a-b-) and Le(a-b+) phenotypes. CONCLUSION: The phenotyping and genotyping of Lewis blood group system reveal a high rate of discordance in the frequencies of Lewis phenotypes among the healthy individuals.

Understanding the demand for phenotyped red blood cell units and requests to perform molecular red blood cell typing for Australian patients.

BACKGROUND: Australian Red Cross Lifeblood has seen a 50 % increase in demand for phenotyped red blood cell (RBC) units between 2016-2018 and a 30 % increase in demand in 2018 to perform molecular RBC typing on patient samples. Lifeblood conducted a survey to understand transfusion laboratory practices for requesting patient phenotyping and/or molecular RBC typing and for selecting phenotyped RBC units in various patient groups. STUDY DESIGN AND METHODS: An electronic Qualtrics survey form was sent to 296 transfusion laboratories with questions designed to understand the practice of selecting phenotyped RBC units and reasons for requesting extended serology or molecular RBC typing. RESULTS: 49 (16.6 %) transfusion laboratories provided data. Reasons to request extended phenotyping and/or molecular RBC typing for patients included; chronic transfusion (n = 31 laboratories), sickle cell disease (n = 25), Thalassemia (n = 23), requirement for anti-CD38 or other MAB therapy (n = 23) or Myelodysplasia (n = 22). Forty-seven transfusion laboratories provided responses with reasons for requesting molecular RBC typing which included: predicting phenotype in patients with multiple antibodies (n = 31), prior to administering anti-CD38 or other MAB therapies (n = 29), for pregnancy related transfusions (n = 28) or for confirming the phenotype of recently transfused patients (n = 18). CONCLUSION: Transfusion laboratory practices indicated that phenotyped RBC units were selected for patients requiring chronic transfusion support and/or undergoing MAB therapy. Requests for molecular RBC typing occurred for more complex patient requirements where serological investigations were not suitable or possible due to reagent restrictions.

Identifying correlations between donor demographics and isohemagglutinin titers as a potential method to screen for low-titer group O whole blood.

BACKGROUND: With more hospitals using low-titer group O whole blood in trauma resuscitation, having an efficient screening method for low-titer donors is critical. Our blood center uses an automated screen for high-titer isohemagglutinins in our platelet donations while collecting detailed donor demographic information. Using this data, we can identify key demographics often associated with titer status, thereby helping develop a donor-triaging method for titering. STUDY DESIGN AND METHODS: Titer results were read with an automated microplate system as either high or low, based on agglutination, with a cutoff equivalent to 1:256 (both anti-A and anti-B). Donor demographic data analyzed included date of donation, blood group, age, gender, and ethnicity. RESULTS: 57,508 donations were collected from 2073 unique donors between 2014 and 2018. We found the following demographics to be correlated with titer status: gender, ABO blood group, age, and ethnicity. Variability in titer status was identified in 215 individuals. This represented around 10 % of the total unique donors and was split equally amongst gender. We also found that donors between the ages of 41-60 ha d the highest likelihood of having variability in titer status, peaking at 13 %, and this proportion declined past age 60. CONCLUSION: Titer status is associated with the following donor demographics: gender, ABO type, age, and ethnicity. We also discovered that variability in titer status is correlated with age. In blood centers that do not have automated and routine titer screening procedure, these findings could be used as a method to efficiently identify low-titer donors a-priori.

Correlation of platelet crossmatch results by Solid Phase Red Cell Adherence Assay (SPRCA) with post-transfusion platelet count increment in adult hemato-oncology patients of a tertiary care oncology centre in India.

AIMS: To assess platelet crossmatch result by SPRCA and find its correlation with post-transfusion platelet count increment among adult hemato-oncology patients. METHODS: A prospective observational pilot study of 50 adult hematologic malignancy patients previously transfused, but not already known to be transfusion-refractory and without any nonimmune causes for inadequate response to platelet transfusion were included after obtaining informed consent. They were transfused one unit of ABO identical single donor platelet. Ten minutes to 1 -h post-transfusion CCI was calculated. CCI ≥ 7500 was considered as adequate response. Post-transfusion crossmatching by SPRCA was performed by using preserved platelet samples from donor units with the serum of the respective patient. Statistical analysis of the correlation between platelet crossmatch results and CCI was done. RESULTS: Out of 50 crossmatches, 78% (39/50) showed compatible and 22% (11/50) showed incompatible results. Among 39 compatible results, 87.2% (34/39) showed adequate CCI and 12.8% (5/39) showed inadequate CCI. Among 11 incompatible results, 18.2% had adequate CCI and 81.8% had inadequate CCI. The difference between the response in terms of CCI to compatible and incompatible crossmatches was found to be statistically significant (p < 0.05). Other variables like age, sex, number of previous transfusions and underlying clinical condition of the patient were not found to have any effect on the compatibility of crossmatch. CONCLUSIONS: Transfusion of crossmatched platelets to non-refractory, multiply transfused hematological malignancy patients without serious illness might provide a small benefit over transfusing randomly selected platelets, though these data must be confirmed with a larger sample size.

Flow cytometry crossmatching to investigate kidney-biopsy-proven, antibody-mediated rejection in patients who develop de novo donor-specific antibodies.

INTRODUCTION: The appearance of de novo donor-specific anti-human leukocyte antigen antibodies (dnDSAs) after kidney transplantation is independently associated with poor long-term allograft outcomes. The objective of the present study was to evaluate the predictive value of a flow cytometry crossmatching (FC-XM) assay after the appearance of dnDSAs related to antibody-mediated allograft rejection (ABMR) after kidney transplantation. MATERIALS AND METHODS: A total of 89 recipients with dnDSAs after transplantation were included. The crossmatching results were compared with the dnDSA profile (the mean fluorescence intensity (MFI), the complement-binding activity, and the IgG subclass profile) and the biopsy's morphological features. RESULTS: Of the 89 patients, 59 (66%) were positive in an FC-XM assay, 17 (19%) had complement-binding DSAs, 55 (62%) were positive for IgG1 and/or IgG3 in a solid phase assay, and 45 (51%) had morphological biopsy features linked to ABMR. CONCLUSION: An FC-XM assay was unable to discriminate between cases with or without ABMR on biopsy findings; it had a low positive predictive value (<70%) and a low negative positive predictive value (<42.9%), taking into account the sensitivity of our assay (limit of detection: DSAs with an MFI >3000). In this context, the height of the MFI of the dnDSAs might be enough for a high positive predictive value for ABMR and additional testing for complement binding activity can remain optional.

Prevalence of clinically significant antibodies in patients undergoing elective surgery in a Nigerian teaching hospital: A case for the type and screen method.

BACKGROUND: Provision of safe and adequate blood is challenging in our environment due to paucity of voluntary donors as well as inappropriate blood ordering and utilization. The type and screen (TS) method (typing of blood group and screening for antibodies) reduces the demand for blood reservation in hospital blood banks. AIMS: The aim of this study is to determine the safety (detection clinically significant antibodies) and cost effectiveness of the TS method compared to the conventional antiglobulin crossmatch (ACM). SETTINGS AND DESIGN AND METHODS: This was a cross-sectional prospective study carried out at the University of Port Harcourt Teaching Hospital (UPTH). 124 participants booked for elective surgeries with no history of blood transfusion or pregnancy were investigated. ACM was performed on all participants' serum against 159 donor red cells. TS was also performed blindly on the same participants' sera, antibody screening was done with three-screen-cells using the gel method. An 11-cell panel was used for antibody identification. Blood utilization was calculated using the crossmatch: transfusion ratio (CTR), probability of transfusion (%T) and transfusion index (TI). RESULTS: Out of the 159 units crossmatched for 124 study participants, only 19 were actually transfused (88.1% not utilized). The prevalence of compatible ACM was 100%, however the TS detected one antibody (0.81%) in a male participant identified as anti-M. The overall CTR, %T and TI were 8.4, 15.6% and 0.16 respectively, with N384,750 ($963.1) wastage in terms of cost. The TS method would have saved N266,000{$665.9} (N1900{4.78} per un-transfused patient). CONCLUSIONS: There was improper utilization of blood in elective surgeries. The TS method identified an antibody not detected by ACM. This would have saved N266,000 {$665.9}, and reduced the demand for blood reservation in the bank. Although The TS method was found not to be significantly different in outcome compared to the ACM, it was found to be cost effective.

Efficacy of HLA virtual cross-matched platelet transfusions for platelet transfusion refractoriness in hematopoietic stem cell transplantation.

BACKGROUND: Cross-matched platelet (cross-matched PLT) transfusion is effective for immune-mediated platelet transfusion refractoriness (PTR), but is more costly and time-consuming for physical cross-match than using standard PLT units. Recent studies have reported the utility of human leucocyte antigens (HLA) virtual cross-matched PLT (HLA-matched PLT) that is defined as HLA-A/B matched or no antibody against donor-specific antigen. Here, we evaluated the effect of HLA-matched PLTs for PTR in post hematopoietic stem cell transplant (HSCT) recipients. STUDY DESIGN AND METHODS: Our study included a total of 241 PLTs in 16 patients who underwent HSCT at Okayama University Hospital between 2010 and 2017, receiving either HLA-matched or cross-matched PLTs. We calculated the 24-hour corrected count increments (CCI-24) to evaluate the effect of PLTs. A CCI-24 ≥ 4500 was considered to be a successful transfusion. RESULTS: We analyzed 139 cross-matched PLTs and 102 HLA-matched PLTs. In the immune-mediated PTR, the rate of successful transfusion was 60.5% for cross-matched PLT and 63.4% for HLA-matched PLT (p = 0.825). On the other hand, the median CCI-24 for cross-matched PLT transfusions and HLA-matched PLT transfusions were 1856 and 5824 (p < 0.001), with a success rate of 28.1 and 54.1% in cases with non-immune-mediated PTR, respectively (p = 0.001). CONCLUSION: The effectiveness of HLA-matched PLT is not inferior to cross-matched PLT. This result indicates that physical cross-match can be omitted in post HSCT PTR.

A novel approach to bedside pretransfusion identity check of blood and its components: the Sandesh Positive-Negative protocol.

BACKGROUND: Blood component mistransfusion is generally due to preventable clerical errors, specifically pretransfusion misidentification of patient/blood unit at bedside. Hence, electronic devices such as barcode scanners are recommended as the standard instrument used to check the patient's identity. However, several healthcare facilities in underdeveloped countries cannot afford this instrument; hence, they usually perform subjective visual assessment to check the patient's identity. This type of assessment is prone to clinical errors, which precipitates significant level of anxiety in the healthcare personnel transfusing the blood unit. Hence, a novel objective method in performing pretransfusion identity check, the 'Sandesh Positive-Negative (SPON) protocol,' was developed. METHODS: A nonrandomized study on bedside pretransfusion identity check was conducted, and 75 health care personnel performed transfusion. The intervention was performed by matching a custom-made negative label with blood component with the positive label of the same patient available at bedside who was about to receive transfusion. RESULTS: In total, 85.3% of the subjects were anxious while performing pretransfusion identity check based on the existing standard practice. After the implementation of the SPON protocol, only 38.7% experienced either mild, moderate or severe anxiety. The overall level of satisfaction also increased from 8.0% to 38.7% and none were dissatisfied. Although only 9.3% were dissatisfied about the existing practice, approximately 70.7% felt the need for a better/additional protocol. Clerical error was not observed. CONCLUSIONS: The SPON protocol is a cost-effective objective method that reduces anxiety and increases satisfaction levels when performing final bedside identity check of blood components.

Blood typing in positive DEA 1 dogs: comparative analysis between immunochromatography, hemagglutination and flow cytometry / Tipificação sanguínea em cães AEC 1 positivo: análise comparativa entre a imunocromatografia, hemoaglutinação e citometria de fluxo

Blood typing techniques have been improved to ensure greater safety for transfusion procedures. Typification for the DEA 1 antigen through flow cytometry should offer more reliability to routine immunohematology in donor and recipient dogs. Currently, the DEA 1 group is starting to be an autosomal dominant allelic system with the DEA 1 negative type and its variations of positivity. The present study investigated the DEA 1 antigen using the techniques of immunochromatography, hemagglutination and flow cytometry. Among the positive animals for the DEA 1 group, typified by flow cytometry, medium intensities of fluorescence were found, which are indicative of weak, moderate and strong antigenicity. This enabled the division of the DEA 1 group into weak positive, moderate positive and strong positive. The blood typing techniques for the DEA 1 group by flow cytometry, agglutination and immunochromatography had positive (Spearman r=0.70) and statistically significant (p>0.0001) correlations.(AU)

As técnicas de tipificação sanguínea vêm sendo aperfeiçoadas para garantir maior segurança aos procedimentos transfusionais. A tipificação para o antígeno AEC 1 com o emprego da citometria de fluxo poderá oferecer mais confiabilidade à rotina da imunohematologia em cães doadores e receptores. Na atualidade, o grupo AEC 1 passou a ser denominado como um sistema alélico autossômico dominante com o tipo AEC 1 negativo e suas variações de positividade. O presente trabalho comparou os resultados de três técnicas utilizadas para a pesquisa do antígeno AEC 1: cromatografia; hemoaglutinação e citometria de fluxo. Dentro dos indivíduos positivos para o grupo AEC 1, tipificados pela citometria de fluxo, foram encontradas intensidades médias de fluorescência indicadoras de antigenicidade fraca, moderada e forte, podendo-se dividir o grupo AEC 1 em positivo fraco, positivo moderado e positivo forte. As técnicas de tipificação sanguínea para o grupo AEC 1 por cromatografia, hemoaglutinação e citometria de fluxo apresentaram correlação positiva (Spearman r=0,70) e estatisticamente significativa (p<0,0001).(AU)

Impact of Novel Monoclonal Antibody Therapeutics on Blood Bank Pretransfusion Testing.

Novel monoclonal antibody therapies are increasing in number and clinical significance as their role in oncologic formularies expands. Anti-CD38 and anti-CD47/SIRPα agents commonly interfere with pretransfusion compatibility testing. Anti-CD38 interference is mitigated by dithiothreitol, which disrupts CD38 antigen on reagent red cells; however, this modification limits rule-out of all clinically significant antibodies. Several anti-CD47 agents are in clinical trials and demonstrate wide variability in pretransfusion testing interference. Modifications to pretransfusion testing can limit interference by anti-CD47 agents. Rapid dissemination of knowledge of these monoclonal antibody agents to the broader transfusion medicine community is paramount for continued patient transfusion safety.

Impact of Genotyping on Selection of Red Blood Cell Donors for Transfusion.

Red blood cell (RBC) antigen phenotyping is an essential component of transfusion compatibility testing. Serology has been the gold standard method, but its low throughput and risk of diagnostic interference in certain situations limits its applicability. Genotyping is useful for phenotyping in these cases, providing a high-throughput and reliable alternative to serology. Genotyping is indicated in several hematology and oncology patient populations. Because genotyping requires a complex testing environment and bears an additional risk of genotype-phenotype discrepancy, its use is currently limited, but it serves as a useful adjunct and may eventually supplant serology as a new gold standard.

Mass-scale red cell genotyping of blood donors: from data visualization to historical antigen labeling and donor recruitment.

Donor red cell genotyping provides efficiencies to identify "in demand" blood donors for transfusion recipients requiring antigen-negative blood. Donor red cell genotype information can be used to label units with historical types and introduced throughout the supply chain from the blood center to the hospital transfusion service and has potential to be used in recruitment strategies.

Linkage and sequence analysis of neutral oligosaccharides by negative-ion MALDI tandem mass spectrometry with laser-induced dissociation.

Mass spectrometry (MS) has become the primary method for high-sensitivity structural determination of oligosaccharides. Fragmentation in the negative-ion MS can provide a wealth of structural information and these can be used for sequence determination. However, although negative-ion MS of neutral oligosaccharide using the deprotonated molecule [M-H]- as the precursor has been very successful for electrospray ionization (ESI), it has only limited success for matrix-assisted laser desorption/ionization (MALDI). In the present study, the features of negative-ion MALDI primary spectra were investigated in detail and the product-ion spectra using [M-H]- and [M+Cl]- as the precursors were carefully compared. The formation of [M-H]- was the main difficulty for MALDI while [M+Cl]- was proved to be useful as alternative precursor anion for MALDI-MS/MS to produce similar fragmentation for sequencing of neutral oligosaccharides. N-(1-naphthyl)ethylenediamine dihydrochloride was then used as both the matrix and the Cl- dopant to evaluate the extent of structural information that can be obtained by negative-ion fragmentation from [M+Cl]- using laser-induced dissociation (LID)-MS/MS for linkage assignment of gluco-oligosaccharides and for typing of blood-group ABO(H) and Lewis antigens on either type 1 or type 2 backbone-chains.

Severe anti-D haemolytic disease of fetal and newborn in rhesus D negative primigravida.

INTRODUCTION: Anti-D alloimmunisation may occur from the blood transfusion or fetomaternal haemorrhage which can lead to haemolytic disease of fetal and newborn (HDFN). The morbidity and mortality of HDFN related to anti-D is significantly reduced after introduction of anti-D prophylaxis and furthermore, anti-D HDFN in RhD negative primigravida is uncommonly seen. CASE REPORT: A case of unusual severe HDFN due to anti-D alloimmunisation in undiagnosed RhD negative primigravida Malay woman is reported here. This case illustrates the possibility of an anamnestic response from previous unknown sensitisation event or the development of anti-D in mid trimester. The newborn expired due to hydrops fetalis and severe anaemia. Antenatally, the mother was identified as RhD positive and thus there was no antenatal antibody screening, antepartum anti-D prophylaxis or close fetal monitoring for HDFN. DISCUSSION: The thorough antenatal ABO and RhD blood grouping with antibody screening is mandatory as part of prevention and early detection of HDFN especially due to anti-D alloimmunisation. Improper management of RhD negative women might lead to severe HDFN including in primigravida.

Blood group genotyping.

Genomics is affecting all areas of medicine. In transfusion medicine, DNA-based genotyping is being used as an alternative to serological antibody-based methods to determine blood groups for matching donor to recipient. Most antigenic polymorphisms are due to single nucleotide polymorphism changes in the respective genes, and DNA arrays that target these changes have been validated by comparison with antibody-based typing. Importantly, the ability to test for antigens for which there are no serologic reagents is a major medical advance to identify antibodies and find compatible donor units, and can be life-saving. This review summarizes the evolving use and applications of genotyping for red cell and platelet blood group antigens affecting several areas of medicine. These include prenatal medicine for evaluating risk of fetal or neonatal disease and candidates for Rh-immune globulin; transplantation for bone marrow donor selection and transfusion support for highly alloimmunized patients and for confirmation of A2 status of kidney donors; hematology for comprehensive typing for patients with anemia requiring chronic transfusion; and oncology for patients receiving monoclonal antibody therapies that interfere with pretransfusion testing. A genomics approach allows, for the first time, the ability to routinely select donor units antigen matched to recipients for more than ABO/RhD to reduce complications. Of relevance, the growth of whole-genome sequencing in chronic disease and for general health will provide patients' comprehensive extended blood group profile as part of their medical record to be used to inform selection of the optimal transfusion therapy.

The disappearance of blood group antigens: A clue to the clinical diagnosis of leukemia.

A 54-year-old male patient was admitted with low-grade intermittent fever not associated with chills. The cell grouping of the patient sample showed O Rh D positive and serum grouping as B, with a discrepancy to be resolved. Series of immunohematological workup was performed to rule out the discrepancy. Reviewing the past proxy history revealed that the patient blood group was B Rh D positive. Bone marrow aspirate showed hypercellularity with increased myelopoiesis and markedly suppressed megakaryopoiesis giving an impression of acute myeloid leukemia and was confirmed by flow cytometry. Based on the current results and past history the blood group of the patient was confirmed to be B Rh D positive with loss of B and H antigens expression on the red cell surface due to underlying leukemia. Correlating the lab results with the clinical details and the case history is an important step in resolving blood grouping discrepancy.

Effects of ABO Matching of Platelet Transfusions in Critically Ill Children.

OBJECTIVES: To determine if transfusing ABO compatible platelets has a greater effect on incremental change in platelet count as compared to ABO incompatible platelets in critically ill children. DESIGN: Secondary analysis of a prospective, observational study. Transfusions were classified as either ABO compatible, major incompatibility, or minor incompatibility. The primary outcome was the incremental change in platelet count. Transfusion reactions were analyzed as a secondary outcome. SETTING: Eighty-two PICUs in 16 countries. PATIENTS: Children (3 d to 16 yr old) were enrolled if they received a platelet transfusion during one of the predefined screening weeks. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Five-hundred three children were enrolled and had complete ABO information for both donor and recipient, as well as laboratory data. Three-hundred forty-two (68%) received ABO-identical platelets, 133 (26%) received platelets with major incompatibility, and 28 (6%) received platelets with minor incompatibility. Age, weight, proportion with mechanical ventilation or underlying oncologic diagnosis did not differ between the groups. After adjustment for transfusion dose, there was no difference in the incremental change in platelet count between the groups; the median (interquartile range) change for ABO-identical transfusions was 28 × 10 cells/L (8-68 × 10 cells/L), for transfusions with major incompatibility 26 × 10 cells/L (7-74 × 10 cells/L), and for transfusions with minor incompatibility 54 × 10 cells/L (14-81 × 10 cells/L) (p = 0.37). No differences in count increment between the groups were noted for bleeding (p = 0.92) and nonbleeding patients (p = 0.29). There were also no differences observed between the groups for any transfusion reaction (p = 0.07). CONCLUSIONS: No differences were seen in the incremental change in platelet count nor in transfusion reactions when comparing major ABO incompatible platelet transfusions with ABO compatible transfusions in a large study of critically ill children. Studies in larger, prospectively enrolled cohorts should be performed to validate whether ABO matching for platelet transfusions in critically ill children is necessary.