Consideration for alpha-gal syndrome in two critically ill persons with group O blood who received group B plasma.

BACKGROUND: The U.S. Centers for Disease Control and Prevention (CDC) has reported increasing rates of alpha-gal syndrome, an allergic response after meat ingestion (AGS). AGS has been associated with prior exposure to tick bites or other biologics characterized by a life-threatening immunoglobulin E (IgE)-mediated hypersensitivity to galactose-alpha-1,3-galactose (alpha-gal) an oligosaccharide structurally similar to the group B antigen on red blood cells (RBC) found in most non-primate mammalian meat and products derived from these mammals. In 2023, Transfusion reported 3 group O recipients of group B plasma in the Washington, D.C. metropolitan area with no history of meat allergy who had anaphylactic transfusion reactions compatible with AGS. AIMS: We investigated allergic reactions in 2 additional patients who received ABO minor-incompatible blood products at 2 hospitals in the D.C. area during fall 2023. METHODS: For both patients, a medical chart review was performed and IgE levels to alpha-gal were measured. RESULTS: The first patient, a 64-year-old, O-positive patient status post heart transplant with no known allergies, was admitted with acute COVID-19 induced antibody-mediated transplant rejection and placed on extracorporeal membrane oxygenation (ECMO). While undergoing plasma exchange (PLEX) (50% albumin/50% fresh frozen plasma (FFP)), the patient tolerated 2 units of group O FFP and 1 unit of group A FFP before becoming hemodynamically unstable during transfusion of 1 unit of B-positive FFP. PLEX was stopped. The patient later died of sepsis from underlying causes. The second patient, a 57-year-old O-positive man with a history of melanoma and neuro fibromatosis type 1, was undergoing an abdominal resection including transfusion of 3 units of O-positive RBC when he suffered hypotension and ventricular tachycardia requiring intraoperative code after receiving 2 units of group B FFP. Hiveswere noted after resuscitation. The patient had a history of tick bites but no known allergies. He is alive 5 months after the possible allergic event. Both patients had full transfusion reaction evaluations and immunology testing results above the positive cutoff for anti-alpha-gal IgE. DISCUSSION AND CONCLUSION: Two patients with O-positive blood and no known allergies experience danaphyl axis after transfusion with group B FFP. The symptoms cannot definitively be imputed to an allergic transfusion reaction, but the presence of IgE against alpha-gal supports an association. Medicating patients with antihistamines and IV steroids pre-transfusion may prevent allergic reactions. Restricting group B plasma-containing products (plasma, platelets, cryoprecipitate) for patients who experience AGS-like symptoms may be considered.

DNA Reference Reagents for Genotyping RH Variants.

Patients who carry Rhesus (RH) blood group variants may develop Rh alloantibodies requiring matched red blood cell transfusions. Serologic reagents for Rh variants often fail to specifically identify variant Rh antigens and are in limited supply. Therefore, red blood cell genotyping assays are essential for managing transfusions in patients with clinically relevant Rh variants. Well-characterized DNA reference reagents are needed to ensure quality and accuracy of the molecular tests. Eight lyophilized DNA reference reagents, representing 21 polymorphisms in RHD and RHCE, were produced from an existing repository of immortalized B-lymphoblastoid cell lines at the Center for Biologics Evaluation and Research/US Food and Drug Administration. The material was validated through an international collaborative study involving 17 laboratories that evaluated each DNA candidate using molecular assays to characterize RHD and RHCE alleles, including commercial platforms and laboratory-developed testing, such as Sanger sequencing, next-generation sequencing, and third-generation sequencing. The genotyping results showed 99.4% agreement with the expected results for the target RH polymorphisms and 87.9% for RH allele agreement. Most of the discordant RH alleles results were explained by a limited polymorphism coverage in some genotyping methods. Results of stability and accelerated degradation studies support the suitability of these reagents for use as reference standards. The collaborative study results demonstrate the qualification of these eight DNA reagents for use as reference standards for RH blood group genotyping assay development and analytical validation.

Clinical Features and Immunogenetic Risk Factors Associated With Additional Autoantibodies in Anti-Transcriptional Intermediary Factor 1γ Juvenile-Onset Dermatomyositis.

OBJECTIVE: Novel autoantibody specificities including anti-CCAR1 were recently discovered in adult patients with anti-transcriptional intermediary factor (TIF1)-positive dermatomyositis (DM) and were associated with attenuated cancer emergence. The aims of the present study were to examine whether these autoantibodies occur in patients with juvenile-onset DM (JDM) and to determine their associated features. METHODS: Sera from 150 patients with anti-TIF1γ autoantibody-positive JDM in a cross-sectional cohort and 90 juvenile healthy controls were assayed for anti-CCAR1, anti-C1Z1, anti-IMMT, anti-TBL1XR1, and anti-Sp4 autoantibodies. Demographics, myositis autoantibodies, clinical features, medications, outcomes, and HLA-DRB1 and HLA-DQA1 alleles were compared between those with and without these autoantibodies. RESULTS: Any one of the anti-TIF1γ-associated autoantibodies was present in 44 patients (29%) overall, including 25 (17%) with anti-Sp4, 22 (15%) with anti-TBL1XR1, 14 (9%) with anti-CCAR1, 2 (1%) with anti-C1Z1, and 2 (1%) with anti-IMMT autoantibodies. These anti-TIF1γ-associated autoantibodies frequently co-occurred. Patients with any of the anti-TIF1γ-associated autoantibodies had less frequent falling (34% [15] vs. 53% [56], P = 0.032) and lower peak muscle enzymes. None of the patients had cancer. Among White patients, HLA-DRB1*03 was protective against an anti-TIF1γ-associated autoantibody (odds ratio 0.20, 95% confidence interval 0.07-0.52). CONCLUSION: Autoantibodies associated with anti-TIF1γ were found in isolation and in combination among a subset of patients with JDM. Patients with these autoantibodies had less severe muscle disease and were not enriched for HLA-DRB1*03. Additional autoantibodies among patients with positive anti-TIF1γ with JDM likely contribute to the heterogeneity of the anti-TIF1γ serologic subgroup.

Breakpoint regions of an RHD-CE(4-9)-D allele and a rare JK allele in a Pacific Islander individual.

BACKGROUND: Among 710 RHD alleles, 3 alleles have been shown to express CcEe antigens and, among 67 hybrid alleles of the RHD gene, 2 alleles have evolved to include RHCE exons 4-9. No breakpoint region had been described for such RHD-CE(4-9)-D hybrid alleles. In the Kidd blood group system, the JK*02N.01 null allele is found with high prevalence in the Polynesian population. We investigated a self-identified Pacific Islander with discrepant serologic and molecular results for his C and Jkb antigens. Another 8 samples with genotype-phenotype discrepancies in the Kidd blood group system were assessed. MATERIALS AND METHODS: A combination of published molecular methods and commercial kits were applied to analyze the RHD, RHCE, and SLC14A1 gene sequences, as were hemagglutination tests to determine the serologic phenotypes. RESULTS: Nucleotide sequencing of the RHD gene in the index case, including relevant intronstretches, and cDNA identified an RHD-CE(4-9)-D hybrid allele. Nucleotide sequencing of his RHCE gene confirmed the presence of 2 RHCE*ce alleles despite expressing the C antigen. Sequencing of his SLC14A1 gene documented the JK*02N.01 null allele. In the other 8 samples, 5 previously known SLC14A1 nucleotide substitutions were identified. The JK*02N.17 allele was determined to be Jkb-positive. DISCUSSION: We determined the 2 breakpoint regions of his RHD-CE(4-9)-D hybrid allele, which was likely distinct from the 2 previously published hybrid alleles due to the differences in the linked RHCE allele. His RHD variant was shown to express the C antigen. An SLC14A1 substitution was underlying his unexpected Jkb-negative phenotype. In a quality improvement project, we resolved 8 samples with similarly discrepant results between Jk serology and red cell genotyping.

Primary oxidative phosphorylation defects lead to perturbations in the human B cell repertoire.

Introduction: The majority of studies on oxidative phosphorylation in immune cells have been performed in mouse models, necessitating human translation. To understand the impact of oxidative phosphorylation (OXPHOS) deficiency on human immunity, we studied children with primary mitochondrial disease (MtD). Methods: scRNAseq analysis of peripheral blood mononuclear cells was performed on matched children with MtD (N = 4) and controls (N = 4). To define B cell function we performed phage display immunoprecipitation sequencing on a cohort of children with MtD (N = 19) and controls (N = 16). Results: Via scRNAseq, we found marked reductions in select populations involved in the humoral immune response, especially antigen presenting cells, B cell and plasma populations, with sparing of T cell populations. MTRNR2L8, a marker of bioenergetic stress, was significantly elevated in populations that were most depleted. mir4485, a miRNA contained in the intron of MTRNR2L8, was co-expressed. Knockdown studies of mir4485 demonstrated its role in promoting survival by modulating apoptosis. To determine the functional consequences of our findings on humoral immunity, we studied the antiviral antibody repertoire in children with MtD and controls using phage display and immunoprecipitation sequencing. Despite similar viral exposomes, MtD displayed antiviral antibodies with less robust fold changes and limited polyclonality. Discussion: Overall, we show that children with MtD display perturbations in the B cell repertoire which may impact humoral immunity and the ability to clear viral infections.

Association of anti-TPM4 autoantibodies with vasculopathic cutaneous manifestations in juvenile dermatomyositis.

OBJECTIVES: AECAs are detected in multiple forms of vasculitis or vasculopathy, including JDM. High levels of tropomyosin alpha-4 chain (TPM4) gene expression in cutaneous lesions and TPM4 protein expression in some endothelial cells (ECs) have been proven. Furthermore, the presence of autoantibodies to tropomyosin proteins have been discovered in DM. We therefore investigated whether anti-TPM4 autoantibodies are an AECA in JDM and are correlated with clinical features of JDM. METHODS: The expression of TPM4 protein in cultured normal human dermal microvascular ECs was investigated by Western blotting. Plasma samples from 63 children with JDM, 50 children with polyarticular JIA (pJIA) and 40 healthy children (HC) were tested for the presence of anti-TPM4 autoantibodies using an ELISA. Clinical features were compared between JDM patients with and without anti-TPM4 autoantibodies. RESULTS: Autoantibodies to TPM4 were detected in the plasma of 30% of JDM, 2% of pJIA (P < 0.0001) and 0% of HC (P < 0.0001). In JDM, anti-TPM4 autoantibodies were associated with the presence of cutaneous ulcers (53%; P = 0.02), shawl sign rash (47%; P = 0.03), mucous membrane lesions (84%; P = 0.04) and subcutaneous edema (42%; P < 0.05). Anti-TPM4 autoantibodies significantly correlated with the use of intravenous steroids and IVIG therapy in JDM (both P = 0.01). The total number of medications received was higher in patients with anti-TPM4 autoantibodies (P = 0.02). CONCLUSION: Anti-TPM4 autoantibodies are detected frequently in children with JDM and are novel myositis-associated autoantibodies. Their presence correlates with vasculopathic and other cutaneous manifestations of JDM that may be indicative of more refractory disease.

Autoantibodies Recognizing Specificity Protein 4 Co-occur With Anti-Transcription Intermediary Factor 1 and Are Associated With Distinct Clinical Features and Immunogenetic Risk Factors in Juvenile Myositis.

OBJECTIVE: Autoantibodies recognizing specificity protein 4 (Sp4) were recently discovered in adults with idiopathic inflammatory myopathies (IIM). Anti-Sp4 autoantibodies co-occurred in patients with anti-transcription intermediary factor 1 (anti-TIF1) autoantibody-positive dermatomyositis (DM) and were associated with a reduced risk of cancer. In the present study, the prevalence and clinical features associated with anti-Sp4 autoantibodies in juvenile-onset IIM were investigated. METHODS: Serum samples from 336 patients with juvenile myositis in a cross-sectional cohort and 91 healthy controls were screened for anti-Sp4 autoantibodies using enzyme-linked immunosorbent assay. Clinical characteristics, outcomes, and HLA alleles of those with and those without anti-Sp4 autoantibodies were compared. RESULTS: Anti-Sp4 autoantibodies were present in 23 patients (7%) with juvenile myositis and were not present in any of the controls. Anti-Sp4 autoantibodies were found among each clinical myositis subgroup. The frequency of TIF1 autoantibody positivity was significantly higher among those with anti-Sp4 autoantibodies (21 [91%] versus 92 [30%], P < 0.001). In the anti-TIF1 autoantibody-positive subgroup, Raynaud's phenomenon (8 [38%] versus 2 [2%], P < 0.001) was more common and peak aspartate aminotransferase was significantly lower in those with anti-Sp4 autoantibodies. None of the patients with anti-Sp4 autoantibodies required a wheelchair. Among White patients, DQA1*04 and DRB1*08 were associated with anti-Sp4 autoantibodies. CONCLUSION: Anti-Sp4 autoantibodies were found in patients with juvenile-onset IIM, predominantly those with coexisting anti-TIF1 autoantibodies. Patients with anti-Sp4 autoantibodies represent a phenotypic subset of anti-TIF1 autoantibody-positive myositis characterized by frequent Raynaud's phenomenon and less pronounced muscle involvement, similar to adults with these autoantibodies. Novel immunogenetic risk factors for White patients with IIM were identified among juveniles with anti-Sp4 autoantibodies.

RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity.

Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.

Low copy numbers of complement C4 and C4A deficiency are risk factors for myositis, its subgroups and autoantibodies.

BACKGROUND: Idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases characterised by myositis-related autoantibodies plus infiltration of leucocytes into muscles and/or the skin, leading to the destruction of blood vessels and muscle fibres, chronic weakness and fatigue. While complement-mediated destruction of capillary endothelia is implicated in paediatric and adult dermatomyositis, the complex diversity of complement C4 in IIM pathology was unknown. METHODS: We elucidated the gene copy number (GCN) variations of total C4, C4A and C4B, long and short genes in 1644 Caucasian patients with IIM, plus 3526 matched healthy controls using real-time PCR or Southern blot analyses. Plasma complement levels were determined by single radial immunodiffusion. RESULTS: The large study populations helped establish the distribution patterns of various C4 GCN groups. Low GCNs of C4T (C4T=2+3) and C4A deficiency (C4A=0+1) were strongly correlated with increased risk of IIM with OR equalled to 2.58 (2.28-2.91), p=5.0×10-53 for C4T, and 2.82 (2.48-3.21), p=7.0×10-57 for C4A deficiency. Contingency and regression analyses showed that among patients with C4A deficiency, the presence of HLA-DR3 became insignificant as a risk factor in IIM except for inclusion body myositis (IBM), by which 98.2% had HLA-DR3 with an OR of 11.02 (1.44-84.4). Intragroup analyses of patients with IIM for C4 protein levels and IIM-related autoantibodies showed that those with anti-Jo-1 or with anti-PM/Scl had significantly lower C4 plasma concentrations than those without these autoantibodies. CONCLUSIONS: C4A deficiency is relevant in dermatomyositis, HLA-DRB1*03 is important in IBM and both C4A deficiency and HLA-DRB1*03 contribute interactively to risk of polymyositis.

Anti-FHL1 autoantibodies in juvenile myositis are associated with anti-Ro52 autoantibodies but not with severe disease features.

OBJECTIVES: Four-and-a-half LIM domains 1 (FHL1) is a muscle-specific protein. Autoantibodies against FHL1 were recently discovered in adults with idiopathic inflammatory myopathies (IIMs) and were found to be associated with clinical features and outcomes indicative of increased disease severity. Anti-FHL1 autoantibodies have not been described in children. Here, the prevalence and clinical features associated with anti-FHL1 autoantibodies were examined in a large North American cohort of juvenile patients with IIM. METHODS: Sera from 338 juvenile IIM patients and 91 juvenile healthy controls were screened for anti-FHL1 autoantibodies by ELISA. Clinical characteristics and HLA alleles of those with and without anti-FHL1 autoantibodies were compared among those with juvenile IIM. RESULTS: Anti-FHL1 autoantibodies were present in 10.9% of juvenile IIM patients and 1.1% of controls. The frequency of anti-FHL1 autoantibodies among clinical and serologic subgroups did not differ. A higher percentage of Asian patients had anti-FHL1 autoantibodies (11% vs 0.7%; P = 0.002). Myositis-associated autoantibodies (MAAs) [odds ratio (OR) 2.09 (CI 1.03, 4.32)], anti-Ro52 autoantibodies specifically [OR 4.17 (CI 1.83, 9.37)] and V-sign rash [OR 2.59 (CI 1.22, 5.40)] were associated with anti-FHL1 autoantibodies. There were no differences in other features or markers of disease severity. No HLA associations with anti-FHL1 autoantibodies in Caucasian myositis patients were identified. CONCLUSION: Anti-FHL1 autoantibodies are present in ∼11% of juvenile IIM patients and commonly co-occur with MAAs, including anti-Ro52 autoantibodies. In contrast to adult IIM, anti-FHL1 autoantibodies in juvenile myositis are associated with V-sign rash but not with other distinctive clinical features or worse outcomes.

International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology Report of Basel and three virtual business meetings: Update on blood group systems.

BACKGROUND AND OBJECTIVES: Under the ISBT, the Working Party (WP) for Red Cell Immunogenetics and Blood Group Terminology is charged with ratifying blood group systems, antigens and alleles. This report presents the outcomes from four WP business meetings, one located in Basel in 2019 and three held as virtual meetings during the COVID-19 pandemic in 2020 and 2021. MATERIALS AND METHODS: As in previous meetings, matters pertaining to blood group antigen nomenclature were discussed. New blood group systems and antigens were approved and named according to the serologic, genetic, biochemical and cell biological evidence presented. RESULTS: Seven new blood group systems, KANNO (defined numerically as ISBT 037), SID (038), CTL2 (039), PEL (040), MAM (041), EMM (042) and ABCC1 (043) were ratified. Two (039 and 043) were de novo discoveries, and the remainder comprised reported antigens where the causal genes were previously unknown. A further 15 blood group antigens were added to the existing blood group systems: MNS (002), RH (004), LU (005), DI (010), SC (013), GE (020), KN (022), JMH (026) and RHAG (030). CONCLUSION: The ISBT now recognizes 378 antigens, of which 345 are clustered within 43 blood group systems while 33 still have an unknown genetic basis. The ongoing discovery of new blood group systems and antigens underscores the diverse and complex biology of the red cell membrane. The WP continues to update the blood group antigen tables and the allele nomenclature tables. These can be found on the ISBT website (http://www.isbtweb.org/working-parties/red-cell-immunogenetics-and-blood-group-terminology/).

Erytra blood group analyser and kode technology testing of SARS-CoV-2 antibodies among convalescent patients and vaccinated individuals.

Surveillance of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic requires tests to monitor antibody formation and prevalence. We detected SARS-CoV-2 antibodies using red cells coated by Kode technology with short peptides derived from the SARS-CoV-2 spike protein (SP). Such modified red cells, called C19-kodecytes, can be used as reagent cells in any manual or automated column agglutination assay. We investigated the presence of SARS-CoV-2 antibodies in 130 samples from COVID-19 convalescent plasma donors using standard manual technique, two FDA-authorized enzyme-linked immunosorbent assay (ELISA) assays and a virus neutralisation assay. The sensitivity of the C19-kodecyte assay was 88%, comparable to the anti-SP and anti-nucleocapsid protein (NCP) ELISAs (86% and 83%) and the virus neutralisation assay (88%). The specificity of the C19-kodecyte assay was 90% (anti-SP 100% and anti-NCP 97%). Likewise, 231 samples from 73 vaccinated individuals were tested with an automated analyser, and we monitored the appearance and persistence of SARS-CoV-2 antibodies. The C19-kodecyte assay is a robust tool for SARS-CoV-2 antibody detection. Automated blood group analyser use enables large-scale SARS-CoV-2 antibody testing for vaccination monitoring in population surveys.

Association of anti-HSC70 autoantibodies with cutaneous ulceration and severe disease in juvenile dermatomyositis.

OBJECTIVES: JDM is an inflammatory myopathy characterized by prominent vasculopathy. AECAs are frequently detected in inflammatory and autoimmune diseases. We sought to determine whether AECAs correlate with clinical features of JDM, and thus serve as biomarkers to guide therapy or predict outcome. METHODS: Plasma samples from 63 patients with JDM, 49 patients with polyarticular JIA and 40 juvenile healthy controls were used to detect anti-heat shock cognate 71 kDa protein (HSC70) autoantibodies, a newly identified AECA, in ELISA assays. Clinical features were compared between JDM patients with and without anti-HSC70 autoantibodies. RESULTS: Anti-HSC70 autoantibodies were detected in 35% of patients with JDM, in 0% of patients with JIA (P < 0.0001) and in 0% of healthy donors (P < 0.0001). Both the presence of cutaneous ulcers (59% vs 17%, P < 0.002) and the use of wheelchairs and/or assistive devices (64% vs 27%, P < 0.007) were strongly associated with anti-HSC70 autoantibodies in JDM. High scores on the severity of myositis damage measures at the time of measurement of anti-HSC70 autoantibodies and an increased number of hospitalizations were also associated with anti-HSC70 autoantibodies. Intravenous immunoglobulin therapy was used more often in anti-HSC70 autoantibody-positive patients. CONCLUSION: Anti-HCS70 autoantibodies are detected frequently in children with JDM and are novel myositis-associated autoantibodies correlating with disease severity.

COVID-19 Antibody Detection and Assay Performance Using Red Cell Agglutination.

Red cells can be labeled with peptides from the SARS-CoV-2 spike protein (C-19 kodecytes) and used as reagent cells for serologic screening of SARS-CoV-2 antibodies. We evaluated 140 convalescent COVID-19 donors and 275 healthy controls using C19-kodecytes. The analytical performance of the C19-kodecyte assay was compared with a virus neutralizing assay and two commercial chemiluminescent antibody tests (Total assay and IgG assay, Ortho). The C19-kodecyte assay detected SARS-CoV-2 antibodies with a sensitivity of 92.8% and specificity of 96.3%, well within the minimum performance range required by FDA for EUA authorization of serologic tests. The Cohen's kappa coefficient was 0.90 indicating an almost perfect agreement with the Total assay. The Spearman's correlation coefficient was 0.20 with the neutralizing assay (0.49 with IgG, and 0.41 with Total assays). The limited correlation in assay reaction strengths suggested that the assays may be influenced by different antibody specificities. The C19-kodecyte assay is easily scalable and may vastly improve test capacity in any blood typing laboratory using its routine column agglutination platforms. IMPORTANCE We recently developed a red cell based assay to detect SARS-CoV-2 antibodies in human plasma. In the current study, we show the hands-on application of this assay in a group of COVID-19 convalescent plasma donors and healthy individuals. We compared our assay against three published assays, including two that are widely used for patient care in the United States. Our assay compared well with all three assays. Our easily scalable assay can be used for population-wide screening of SARS-CoV-2 antibody status. It can be readily established in any hospital blood bank worldwide using its routine equipment.

HLA associations, somatic loss of HLA expression, and clinical outcomes in immune aplastic anemia.

Immune aplastic anemia (AA) features somatic loss of HLA class I allele expression on bone marrow cells, consistent with a mechanism of escape from T-cell-mediated destruction of hematopoietic stem and progenitor cells. The clinical significance of HLA abnormalities has not been well characterized. We examined the somatic loss of HLA class I alleles and correlated HLA loss and mutation-associated HLA genotypes with clinical presentation and outcomes after immunosuppressive therapy in 544 AA patients. HLA class I allele loss was detected in 92 (22%) of the 412 patients tested, in whom there were 393 somatic HLA gene mutations and 40 instances of loss of heterozygosity. Most frequently affected was HLA-B*14:02, followed by HLA-A*02:01, HLA-B*40:02, HLA-B*08:01, and HLA-B*07:02. HLA-B*14:02, HLA-B*40:02, and HLA-B*07:02 were also overrepresented in AA. High-risk clonal evolution was correlated with HLA loss, HLA-B*14:02 genotype, and older age, which yielded a valid prediction model. In 2 patients, we traced monosomy 7 clonal evolution from preexisting clones harboring somatic mutations in HLA-A*02:01 and HLA-B*40:02. Loss of HLA-B*40:02 correlated with higher blood counts. HLA-B*07:02 and HLA-B*40:01 genotypes and their loss correlated with late-onset of AA. Our results suggest the presence of specific immune mechanisms of molecular pathogenesis with clinical implications. HLA genotyping and screening for HLA loss may be of value in the management of immune AA. This study was registered at clinicaltrials.gov as NCT00001964, NCT00061360, NCT00195624, NCT00260689, NCT00944749, NCT01193283, and NCT01623167.

Erytra Blood Group Analyser and Kode Technology testing of SARS-CoV-2 antibodies among convalescent patients and vaccinated individuals.

Surveillance of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic requires tests to monitor antibody formation and prevalence. We detected SARS-CoV-2 antibodies using red cells coated by Kode technology with short peptides derived from the SARS-CoV-2 spike protein. Such modified red cells, called C19-kodecytes, can be used as reagent cells in any manual or automated column agglutination assay. We investigated the presence of SARS-CoV-2 antibodies in 130 samples from COVID-19 convalescent plasma donors using standard manual technique, two FDA authorized ELISA assays and a virus neutralisation assay. The sensitivity of the C19-kodecyte assay was 88%, comparable to the anti-SP and anti-NCP ELISAs (86% and 83%) and the virus neutralisation assay (88%). The specificity of the C19-kodecyte assay was 90% (anti-SP 100% and anti-NCP 97%). Likewise, 231 samples from 73 vaccinated individuals were tested with an automated analyser and we monitored the appearance and persistence of SARS-CoV-2 antibodies. The C19-kodecyte assay is a robust tool for SARS-CoV-2 antibody detection. Automated blood group analyser use enables large-scale SARS-CoV-2 antibody testing for vaccination monitoring in population surveys.