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BACKGROUND: Weak D types are thought to express rather quantitative than qualitative D antigen variants. Distinct type-specific phenotypes and weak D cases with anti-D alloimmunization, however, suggest a variable degree of D antigen alteration. STUDY DESIGN AND METHODS: Variant D types were investigated by use of molecular typing, RHD sequencing, extended serologic D antigen investigations, and flow cytometric D antigen density determination. RESULTS: Two novel weak D types were discovered, termed weak D type 31 and 32 with single RHD nucleotide substitutions coding for amino acid exchanges in predicted intracellular RhD polypeptide stretches, with antigen densities of approximately 130 and 50 D sites per red blood cell, respectively. Adsorption-elution technique-supported D epitope mapping of these two weak D types, the recently described weak D type 26, and of the most common Central European weak D types (weak D types 1, 2, 3, 4.0, and 4.1) demonstrated the expression of all tested D epitopes. In contrast, a distinct D epitope loss was detected in weak D type 15 and partial D control samples. CONCLUSION: All novel and prevalent weak D types expressed all tested D epitopes. Our results indicate that adsorption-elution techniques may be of advantage whenever D epitope loss is suspected in extremely weak D variants. [ABSTRACT FROM AUTHOR]

Routine ABO blood group typing of apparently healthy individuals sporadically uncovers unexplained mixed-field reactions. Such blood group discrepancies can either result from a haematopoiesis-confined or body-wide dispersed chimerism or mosaicism. Taking the distinct clinical consequences of these four different possibilities into account, we explored the responsible cause in nine affected individuals. Genotype analyses revealed that more than three-quarters were chimaeras (two same-sex females, four same-sex males, one sex-mismatched male), while two were mosaics. Short tandem repeat analyses of buccal swab, hair root and nail DNA suggested a body-wide involvement in all instances. Moreover, genome-wide array analyses unveiled that in both mosaic cases the causative genetic defect was a unique copy-neutral loss of heterozygosity encompassing the entire long arm of chromosome 9. The practical transfusion- or transplantation-associated consequences of such incidental discoveries are well known and therefore easily manageable. Far less appreciated is the fact that such findings also call attention to potential problems that directly ensue from their specific genetic make-up. In case of chimerism, these are the appearance of seemingly implausible family relationships and pitfalls in forensic testing. In case of mosaicism, they concern with the necessity to delineate innocuous pre-existent or age-related from disease-predisposing and disease-indicating cell clones., (© 2024 The Author(s). British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Introduction: The coronavirus disease (COVID-19) pandemic gave rise to studies investigating the association of ABO blood group with COVID-19 susceptibility. It is hypothesized that ABO antibodies might play a role in neutralizing SARS-CoV-2. However, ABO antibodies were exclusively analyzed in blood samples. Investigation of ABO antibodies in saliva, an easy-to-obtain surrogate for respiratory secretions, may provide novel insights into mucosal immunity crucial in early defense against respiratory pathogens., Methods: In this study, saliva and serum samples from healthy individuals with known blood groups were investigated using a flow cytometric method for separate anti-A/anti-B IgA, IgM, and IgG class antibody detection. Saliva samples were additionally tested using hemagglutination-based neutral and indirect anti-human globulin test gel cards. This method comparison was complemented by dilution experiments with a high-titer anti-A/anti-B WHO standard., Results: In saliva, IgA was the most abundant ABO antibody class, followed by IgM; IgG was detected only in low levels in all non-AB blood types. In serum, IgM was the predominant ABO antibody class in all non-AB blood types, followed by IgA and IgG, the latter mainly detected in group O individuals. Saliva and serum samples of group O individuals yielded the highest variability of ABO-specific antibody levels. Regardless of sample material and blood type, major interindividual differences in ABO antibody reactivities were recorded. Antibody levels correlated moderately between these two body fluids. There were no significant sex and age-group differences in ABO antibody levels in both serum and saliva. WHO standard dilution experiments yielded technique-specific limits of detection, illustrating the inherent differences of immunofluorescence versus agglutination., Conclusion: For the first time, salivary ABO antibodies were investigated by separate detection of the three most relevant antibody classes IgA, IgM, and IgG in a healthy cohort. This study opens new perspectives regarding mucosal ABO antibody class profiles and their potential influence on respiratory infections., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2022 by The Author(s). Published by S. Karger AG, Basel.)

Individuals with ABO type O, naturally possessing anti-A and anti-B antibodies in their serum, are underrepresented among patients infected with SARS-CoV-2 compared with healthy controls. The ABO antibodies might play a role in the viral transmission. Therefore, we aimed to quantify anti-A/anti-B, including their subclasses IgM, IgG and IgA, in the serum and saliva of Caucasians (n = 187) after mild COVID-19 to compare them with individuals who had never been infected with SARS-CoV-2. Two samples were collected within two months after the diagnosis (median days: 44) and two months later. ABO antibodies were determined by flow cytometry. Additionally, total IgA in saliva and antibodies specific to SARS-CoV-2 were tested by ELISA. COVID-19 convalescents had significantly lower levels of anti-A/anti-B IgM, IgG and IgA in their serum than control subjects (p < 0.001). Interestingly, no significant differences were observed in saliva. ABO antibody levels remained stable over the period considered. No relation of ABO to the level of SARS-CoV-2-specific antibodies was observed. Total IgA was lower in convalescents than in controls (p = 0.038). Whereas ABO antibodies in the saliva may not contribute to the pathogenesis of COVID-19, individual pre-existing high serum concentrations of anti-A/anti-B may have a protective effect against SARS-CoV-2 infection.

Four new HLA class I alleles were characterized by next-generation sequencing and haplotypes determined., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: Medical laboratories may, at their own discretion, exceed but not undercut regulatory quality requirements. Available economic resources, however, may drive or hinder eagerness to exceed minimum requirements. Depending on the respective scopes of regulatory and economic framework conditions, differing levels of quality efforts to safeguard laboratory performance can be anticipated. However, this has not yet been investigated., Methods: Immunohaematology external quality assessment (EQA) results collected by 26 EQA providers from their participant laboratories in 73 countries from 2004 to 2019 were evaluated. Error rates were aggregated in groups according to the respective national regulatory and economic framework conditions, to whether or not expert advice was provided in case of incorrect results, and the frequency of EQA samples., Results: These representative data indicate no association between national regulatory (mandatory participation in EQA, monitoring of performance of individual laboratories by authorities, financial consequences of incorrect results) and economic (level of national income, share of national health expenditure) conditions to the quality performance of medical laboratories in immunohaematology. However, EQA providers' support for laboratories in the event of incorrect results appear to be associated with lower error rates, but a high EQA sample frequency with higher error rates., Conclusions: Further research into the impact of introducing or changing services of EQA providers is needed to confirm the results found in this first of its kind study., (© 2022 Walter de Gruyter GmbH, Berlin/Boston.)

Competing Interests: T.R.K. has Takeda stock interest. All other authors declare no conflict of interests.

The quantification of donor-derived cell-free DNA (ddcfDNA) in recipient's plasma is a novel, but technically challenging noninvasive method to assist the diagnosis of acute rejection (AR). A quantitative real-time PCR (qPCR) approach targeting insertion/deletion polymorphisms (INDEL) was adapted to measure ddcfNA in plasma samples from 29 kidney transplant recipients obtained at time of clinically indicated biopsies (eight patients with a histologically verified AR, nine with borderline rejection and 12 without evidence of rejection). Measured ddcfDNA levels of smaller INDEL amplicon targets differed significantly (P = 0.016, Kruskal-Wallis H test) between recipients with biopsy-proven AR (median 5.24%; range 1.00-9.03), patients without (1.50%; 0.41-6.50) and patients with borderline AR (1.91%; 0.58-5.38). Similarly, pairwise testing by Mann-Whitney U-tests revealed significant differences between recipients with AR and without AR (P = 0.012) as well as patients with AR and borderline histology (P = 0.015). Receiver operating characteristic (ROC) analysis revealed an area under the ROC curve for discriminating AR and non-AR biopsies of 0.84 (95% CI: 0.66-1.00). The determined cutoff value of 2.7% ddcfDNA showed a sensitivity of 0.88 (95% CI: 0.63-1.00) and specificity of 0.81 (95% CI: 0.64-0.98). INDEL qPCR represents a novel method to quantify ddcfDNA on standard qPCR instruments within 6-8 h with high sensitivity and specificity to detect AR., (© 2019 The Authors. Transplant International published by John Wiley & Sons Ltd on behalf of Steunstichting ESOT.)

Background: As some errors in pretransfusion testing remain unrecognized, error rates and the resulting need for corrective measures are probably underestimated. External quality assessment (EQA) schemes could provide valuable input for identifying error-prone laboratory tests because they are designed to monitor test performance and errors. So far, however, there are only limited published data on error rates in such schemes., Methods: The types and incidence of incorrect results in an EQA scheme for red cell immunohematology with 187 participating laboratories were examined. The results of 58 distributions between 1999 and 2017 were evaluated, considering also the employed determination methods., Results: Out of a total of 58,726 results, 563 (0.96%) were incorrect. Error rates were 5.45% for antibody identification, 1.39% for Rh phenotyping, 0.83% for serologic cross-match, 0.60% for direct antiglobulin test, 0.20% for Kell phenotyping, 0.16% for antibody screening, and 0.14% for ABO phenotyping. During the observation period, 53 participants reported error-free results, while 37 reported one incorrect result and 97 repeatedly reported incorrect results for one or more analytes. Error rates obtained by manual methods significantly surpassed those obtained by automated methods (1.04 vs. 0.42%). The introduction of double testing with two different systems reduced error rates in Rh phenotyping from 1.55 to 0.50%., Conclusion: Risk assessment should consider that error rates in pretransfusion test results vary. These data delineate the error risk potential of individual laboratory tests and thus should aid in tailoring appropriate improvement measures., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2019 by S. Karger AG, Basel.)

Spontaneous Rh blood group changes are a striking sign, reported to occur mainly in patients with hematologic disorders. Upon routine blood grouping, 2 unrelated individuals showed unexplained mixed red cell phenotype regarding the highly immunogenic c antigen (RH4), clinically relevant for blood transfusion and fetomaternal incompatibility. About half of their red cells were c-positive, whereas the other half were c-negative. These apparently hematologically healthy females had no history of transfusion or transplantation, and they tested negative for chimerism. Genotyping of flanking chromosome 1 microsatellites in blood, finger nails, hair, leukocyte subpopulations, and erythroid progenitor cells showed partial loss of heterozygosity encompassing the RHD/RHCE loci, spanning a 1p region of 26.7 or 42.4 Mb, respectively. Remarkably, in one case this was detected in all investigated tissues, whereas in the other, exclusively myeloid cells showed loss of heterozygosity. Both carried the RhD-positive haplotypes CDe and the RhD-negative haplotype cde RHD/RHCE genotypes of single erythroid colonies and dual-color fluorescent in situ hybridization analyses indicated loss of the cde haplotype and duplication of the CDe haplotype in the altered cell line. Accordingly, red cell C antigen (RH2) levels of both propositae were higher than those of heterozygous controls. Taken together, the Rhc phenotype splitting appeared to be caused by deletion of a part of 1p followed by duplication of homologous stretches of the sister chromosome. In one case, this phenomenon was confined to myeloid stem cells, while in the other, a pluripotent stem cell line was affected, demonstrating somatic mosaicism at different stages of ontogenesis., (Copyright© 2019 Ferrata Storti Foundation.)

Background and Objectives: Classical neutrophil-reactive antibody testing depends on the quick isolation of neutrophils from freshly taken whole blood. To allow a better logistic preparation before testing, the influence of time interval between venipuncture and cell isolation has been evaluated in this study., Materials and Methods: Neutrophils and whole leukocytes were isolated from EDTA whole blood immediately (T0) as well as 4, 8 and 24 h after blood donation (T4, T8 and T24). These cells were tested against reference sera containing antibodies against HNA-1b, -2, -3a and HLA class I using granulocyte aggregation test (GAT), microscopic granulocyte immunofluorescence test (GIFT) and flow-cytometric white blood cell immunofluorescence test (Flow-GIFT/WIFT)., Results: GAT was the most error-prone test displaying overall weaker aggregation strengths already at T4 (overall accuracy OA = 0.72, κ = 0.58). GIFT results showed good agreement at T4 (OA = 0.86, κ = 0.79) and remained stable until T8, while test results were slightly impaired at T24 (OA = 0.71, κ = 0.55). Flow-GIFT/WIFT was identified as the most robust screening method, remaining stable even at T24. Calculated ratios (sample/negative control) decreased non-significantly and remained highly above the cut-off in all samples., Conclusion: Acceptable time limits for cell isolation are different for each screening method investigated. For GAT, cell isolation should be performed within 4 h, while GIFT tolerates a neutrophil isolation delay of 8 h. Flow-GIFT/WIFT isolation can be performed even after 24 h without impairment of the results. Using the latter test as a stand-alone pre-screening test, whole blood can be used from donors who are not directly accessible., (Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Background ISO 9001 and ISO 15189 have been established as continuative models for quality systems beyond national laws, mandatory standards and guidelines of expert associations regarding analytical and organisational performance of medical laboratories and transfusion services. Although widely used, their impact on laboratory performance has not been investigated. Methods We retrospectively analysed the results of 167 laboratories in 59 distributions of the Austrian red cell immunohaematology external quality assessment (EQA) scheme in the years 1999-2017. The performance for each parameter and trends of individual participants were compared with respect to certification or accreditation status of participants' quality systems and to laboratory type. Results Considering more than 52,000 EQA results, the absence or presence of a laboratory quality management system showed different error rates. Laboratories with ISO 9001 or ISO 15189 certification/accreditation had 0.7% incorrect results, while this rate was doubled without such quality systems (1.4%, p=0.0002). Statistically significant error reductions were seen upon ISO 9001/ISO 15189 implementation (1.3% before vs. 0.7% after; p=0.0468). Transfusion services had fewer errors (0.9%) compared to hospital and independent laboratories (both 1.2%). Conclusions Implementation and maintenance of quality systems according to ISO 9001 or ISO 15189 as well as laboratory specialisation result in better analytical performance as can be seen in immunohaematology EQA results. The conclusion is that these results apply to other laboratory tests and perhaps to other areas of health care.

Linkage disequilibria (LD) between alleles and haplotypes of human leucocyte antigen, locus A (HLA) and STR loci located in the human major histocompatibility complex were analyzed in order to investigate whether or not HLA alleles and haplotypes are predictable by alleles or haplotypes of HLA STRs. Standardized genotyping of eight STR loci (D6S2972, D6S2906, D6S2691, D6S2678, D6S2792, D6S2789, D6S273, and DQIV) was performed by CE on 600 individuals from 150 Austrian Caucasoid families with known HLA-A,-B,-C and -DRB1 typing. From those, 576 full haplotypes of four HLA and eight STR loci were obtained. Haplotypes of two flanking STRs predicted HLA alleles and two-locus HLA haplotypes better than single STR alleles, except HLA-DRB1 alleles (92% were in LD with DQIV alleles only). A percentage of 65-86% of three and four-locus HLA haplotypes were in LD with haplotypes of three, four, and eight of their flanking STR loci including numerous clear-cut predictions (20-61%). All eight and a set of the four most informative STR loci D6S2972, D6S2678, D6S2792, and DQIV could identify all HLA identical and nonidentical siblings in 138 pairs of siblings. The results of this proof of concept study in Austrian Caucasoids show, that HLA STRs can aid the definition of HLA-A,-B,-C,-DRB1 haplotypes and the selection of sibling donors for stem cell transplantation., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Background and Objectives: Granulocyte-reactive antibodies can cause autoimmune and neonatal immune neutropenias as well as transfusion-related acute lung injury. The classical antibody-detection methods granulocyte aggregation test (GAT), granulocyte immunofluorescence test (GIFT) and monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) are time-consuming and technically challenging. In recent years, flow cytometric white blood cell immunofluorescence test (Flow-WIFT) and the microbeads assay LabScreen® Multi have emerged and are still subject of evaluation. These serological tests were compared on a screening and specification level., Materials and Methods: For screening, the combination of GAT/GIFT was compared to Flow-WIFT testing 333 samples. Positive samples were further analysed with MAIGA and LabScreen® Multi., Results: Granulocyte aggregation test/GIFT detected 77 positive samples, Flow-WIFT found 108 granulocyte-reactive samples. Six Samples were only positive in GAT/GIFT, and 37 samples were only positive in Flow-WIFT (κ = 0.682). Antibody specification with MAIGA and the microbeads assay confirmed granulocyte-reactivity in 83 cases with 70 matching results (κ = 0.742). However, out of six detected human neutrophil antigen (HNA) reactivities only two specificities matched in both assays., Conclusion: Flow-WIFT may be a valuable addition to GIFT for granulocyte-reactive antibody screening. MAIGA remains the most reliable laboratory method for antibody specification., (© 2014 International Society of Blood Transfusion.)

Eastern Austria is neighbouring regions with ongoing West Nile virus (WNV) transmissions. Three human WNV infections had been diagnosed during the past decade in Austria. The Austrian Red Cross Blood Service (ARC-BS) started a first voluntary screening for WNV in blood donors from Eastern Austria by Nucleic Acid Testing (NAT) in June 2014. This is also the most extensive WNV surveillance programme in humans in Austria so far. In August 2014, one autochthonous WNV infection was detected in a blood donor from Vienna. By now, one in 67,800 whole blood donations was found to be positive for WNV RNA., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Sequenced allelic ladders are a prerequisite for reliable genotyping of short tandem repeat (STR) polymorphisms and consistent results across instrument platforms. For eight STR-loci located on the short arm of chromosome 6 (6p21.3), a sequenced based nomenclature was established according to international recommendations. Publicly available reference DNA samples were sequenced enabling interested laboratories to construct their own allelic ladders. Three tetrameric (D6S2691, D6S2678, DQIV), one trimeric (D6S2906) and four dimeric repeat loci (D6S2972, D6S2792, D6S2789, D6S273) were investigated. Apart from the very complex sequence structure at the DQIV locus, three loci showed a compound and four loci a simple repeat pattern. In the flanking regions of some loci additional single nucleotide and insertion/deletion polymorphisms occurred as well as sequence polymorphisms within the repeat region of alleles with the same length. In an Austrian Caucasoid population sample (n=293) between eight and 22 alleles were found. No significant deviation from Hardy-Weinberg expectations was observed, the power of discrimination ranged from 0.826 to 0.978. The loci cover the HLA-coding region from HLA-A to HLA-DQB1 and can be used for a better definition of HLA haplotypes for population and disease association studies, recombination point mapping, haematopoietic stem cell transplantation as well as for identity and relationship testing., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Many different factors influence the propensity of transfusion recipients and pregnant women to form red blood cell alloantibodies (RBCA). RBCA may cause hemolytic transfusion reactions, hemolytic disease of the fetus and newborn and may be a complication in transplantation medicine. Antigenic differences between responder and foreign erythrocytes may lead to such an immune answer, in part with suspected specific HLA class II associations. Biochemical and conformational characteristics of red blood cell (RBC) antigens, their dose (number of transfusions and pregnancies, absolute number of antigens per RBC) and the mode of exposure impact on RBCA rates. In addition, individual circumstances determine the risk to form RBCA. Responder individuality in terms of age, sex, severity of underlying disease, disease- or therapy-induced immunosuppression and inflammation are discussed with respect to influencing RBC alloimmunization. For particular high-risk patients, extended phenotype matching of transfusion and recipient efficiently decreases RBCA induction and associated clinical risks.

The DNA Commission of the International Society of Forensic Genetics (ISFG) regularly publishes guidelines and recommendations concerning the application of DNA polymorphisms to the question of human identification. Previous recommendations published in 2000 addressed the analysis and interpretation of mitochondrial DNA (mtDNA) in forensic casework. While the foundations set forth in the earlier recommendations still apply, new approaches to the quality control, alignment and nomenclature of mitochondrial sequences, as well as the establishment of mtDNA reference population databases, have been developed. Here, we describe these developments and discuss their application to both mtDNA casework and mtDNA reference population databasing applications. While the generation of mtDNA for forensic casework has always been guided by specific standards, it is now well-established that data of the same quality are required for the mtDNA reference population data used to assess the statistical weight of the evidence. As a result, we introduce guidelines regarding sequence generation, as well as quality control measures based on the known worldwide mtDNA phylogeny, that can be applied to ensure the highest quality population data possible. For both casework and reference population databasing applications, the alignment and nomenclature of haplotypes is revised here and the phylogenetic alignment proffered as acceptable standard. In addition, the interpretation of heteroplasmy in the forensic context is updated, and the utility of alignment-free database searches for unbiased probability estimates is highlighted. Finally, we discuss statistical issues and define minimal standards for mtDNA database searches., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Granulocyte-reactive antibodies may cause transfusion-related acute lung injury (TRALI) and immune neutropenias. Risk factors for their acquisition other than previous alloexposition are largely unknown. In addition to the known association between human leucocyte antigen alloantibodies and red blood cell alloimmunization in selected cohorts of transfused patients, this study investigated a possible extension of this association to granulocyte-reactive antibodies in women with a history of pregnancy. The overall prevalence of granulocyte-reactive antibodies in 333 samples from women with a history of pregnancy (143 samples containing red cell alloantibodies) was 23·1%. The prevalence in the red cell-alloimmunized group (32·9%) was significantly higher than in controls (15·8%, P < 0·001). This could suggest that some individuals may be strong immunological responders, forming alloantibodies more readily than others., (© 2014 International Society of Blood Transfusion.)

The Major Histocompatibility Complex Class I Chain-Related Gene A (MICA) is located 46.4 Kb centromeric to HLA-B locus on chromosome 6; 84 alleles have been described so far. To assess the distribution of MICA alleles in an Austrian population, 322 unrelated Austrian blood donors have been typed for MICA by direct sequencing of amplified exons 2-5; sequencing of exon 6 and separating alleles by haplotype specific primers or by cloning was performed to resolve ambiguities. HLA-B was typed at low level resolution and linkage disequilibrium was determined. We observed 20 already known and four novel MICA alleles. MICA*008:01/04 was the most frequent allele (42%), followed by MICA*002:01 (11%) and MICA*009:01 (9%), three alleles (MICA*029, *067 and *068) were observed only once. No deviation from the Hardy Weinberg equilibrium was observed. Linkage disequilibrium between MICA and HLA-B alleles was observed, most extensively between MICA*008:01/04 and HLA-B*07. Our population data are in agreement with other European populations. The fact that four novel alleles have been observed indicates that the polymorphism of MICA is larger than currently estimated., (Copyright © 2013 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

DNA profiling of biological material from scenes of crimes is often complicated because the amount of DNA is limited and the quality of the DNA may be compromised. Furthermore, the sensitivity of STR typing kits has been continuously improved to detect low level DNA traces. This may lead to (1) partial DNA profiles and (2) detection of additional alleles. There are two key phenomena to consider: allelic or locus 'drop-out', i.e. 'missing' alleles at one or more genetic loci, while 'drop-in' may explain alleles in the DNA profile that are additional to the assumed main contributor(s). The drop-in phenomenon is restricted to 1 or 2 alleles per profile. If multiple alleles are observed at more than two loci then these are considered as alleles from an extra contributor and analysis can proceed as a mixture of two or more contributors. Here, we give recommendations on how to estimate probabilities considering drop-out, Pr(D), and drop-in, Pr(C). For reasons of clarity, we have deliberately restricted the current recommendations considering drop-out and/or drop-in at only one locus. Furthermore, we offer recommendations on how to use Pr(D) and Pr(C) with the likelihood ratio principles that are generally recommended by the International Society of Forensic Genetics (ISFG) as measure of the weight of the evidence in forensic genetics. Examples of calculations are included. An Excel spreadsheet is provided so that scientists and laboratories may explore the models and input their own data., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: Due to the fact that the ABO and D system is inherited independently from the HLA system, approximately 40% of allogeneic hematopoietic stem cell transplants (HSCT) are performed across the blood group barrier. Reports on the development of de novo anti-D in patients undergoing reduced-intensity conditioning (RIC) followed by D-mismatched allogeneic HSCT are rare. The objective of this study was to evaluate the frequency of anti-D alloimmunization after D-mismatched HSCT following RIC and its prognostic impact on transplant outcome., Study Design and Methods: Forty patients with hematologic diseases who underwent D-mismatched HSCT were retrospectively analyzed: 19 D- patients with a D+ donor and 21 D+ patients with a D- donor. Routine serologic testing for blood group typing and antibody screening was performed by a column agglutination method every time when transfusion of red blood cell units was requested and in the posttransplantation course to demonstrate establishment of donor ABO type and to detect alloimmunization., Results: After a median serologic follow-up of 21 (range, 0 to 73) months after HSCT, anti-D was identified in 2 of 21 (10%) D+ patients receiving a D- transplant, 23 and 34 months after HSCT. None of the 19 D- patients with a D+ donor developed an anti-D., Conclusion: We observed an infrequent de novo anti-D formation that is more likely in D+ recipients of D- grafts. However, the development of anti-D does not normally impair the transplant outcome and is not of clinical relevance in the posttransplant course., (© 2011 American Association of Blood Banks.)

Well defined estimates of mutation rates are a prerequisite for the use of short tandem repeat (STR-) loci in relationship testing. We investigated 65 isolated genetic inconsistencies, which were observed within 50,796 allelic transfers at 23 STR-loci (ACTBP2 (SE33), CD4, CSF1PO, F13A1, F13B, FES, FGA, vWA, TH01, TPOX, D2S1338, D3S1358, D5S818, D7S820, D8S1132, D8S1179, D12S391, D13S317, D16S539, D17S976, D18S51, D19S433, D21S11) in Caucasoid families residing in Austria and Switzerland. Sequencing data of repeat and flanking regions and the median of all theoretically possible mutational steps showed valuable information to characterise the mutational events with regard to parental origin, change of repeat number (mutational step size) and direction of mutation (losses and gains of repeats). Apart from predominant single-step mutations including one case with a double genetic inconsistency, two double-step and two apparent four-step mutations could be identified. More losses than gains of repeats and more mutations originating from the paternal than the maternal lineage were observed (31 losses, 22 gains, 12 losses or gains and 47 paternal, 11 maternal mutations and 7 unclear of parental origin). The mutation in the paternal germline was 3.3 times higher than in the maternal germline. The results of our study show, that apart from the vast majority of single-step mutations rare multi-step mutations can be observed. Therefore, the interpretation of mutational events should not rigidly be restricted to the shortest possible mutational step, because rare but true multi-step mutations can easily be overlooked, if haplotype analysis is not possible., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Background and Objectives: One to two per cent of patients in need of red cell transfusion carry irregular antibodies to red blood cell (RBC) antigens and have to be supplied with specially selected blood units. To be able to respond to those requests, blood centres have to screen a significant number of donors for a variety of antigens serologically, which is a costly and through the shortage of reagents, also limited procedure. To make this procedure more efficient, the Austrian Red Cross has developed a genotyping assay as an alternative approach for high throughput RBC typing., Materials and Methods: A multiplex polymerase chain reaction (PCR) assay was designed for typing 35 RBC antigens in six reaction mixes. The assay includes both common as well as high-frequency-alleles: MNS1, MNS2, MNS3 and MNS4; LU1, LU2, LU8 and LU14; KEL1, KEL2, KEL3, KEL4, KEL6, KEL7, KEL11, KEL17 and KEL21; FY1, FY2, FYB(WK) and FY0 (FYB(ES)); JK1 and JK2; DI1, DI2, DI3 and DI4; YT1 and YT2; DO1 and DO2; CO1 and CO2; IN1 and IN2. The assay was validated using 370 selected serologically typed samples. Subsequently 6000 individuals were screened to identify high frequency antigen (HFA)-negative donors and to facilitate the search for compatible blood for alloimmunized patients., Results: All controls showed complete concordance for the tested markers. The screening of 6000 donors revealed 57 new HFA-negative donors and the blood group database was extended by approximately 210,000 results., Conclusion: The study shows that in practice, this high-throughput genotyping assay is feasible, fast and provides reliable results. Compared to serological testing, this molecular approach is also very cost-efficient., (© 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.)

Between 1988 and 2007, international searches for matched unrelated donors (MUDs) were performed for 1586 Austrian patients. Between 2004 and 2007, a MUD was identified for 76.7% of the patients. Between 1996 and 2003, a donor was identified for 71.3% of the patients, and between 1988 and 1995, only for 53.4% of the patients. Search times of successful searches decreased from 7.7 months in the first period to 1.7 months in the period from 2004 to 2007. However, transplants were not performed in all cases in which a donor was found: only in 61.6% of the patients between 2004 and 2007, in 53.4% between 1996 and 2003 and in 29.6% between 1988 and 1995. Multivariate analysis determined that having a common HLA type was the most important variable impacting on finding a MUD for a patient. Factors that most strongly influence a patient's access to transplant were the patient's European origin and a short time between diagnosis and start of donor search. The strongest factor for both finding a donor and being transplanted was a search being performed during more recent years: patients' chances increased from year to year.