Transfusions in autoimmune hemolytic anemias: Frequency and clinical significance of alloimmunization.

BACKGROUND: Autoimmune hemolytic anemia (AIHA) may be associated with transfusion reactions and risk of alloimmunization. OBJECTIVES: To evaluate the transfusion policy and rate of alloimmunization and its clinical significance in AIHA. METHODS: Data from 305 AIHA patients followed at a reference hematologic Center in Milan, Italy from 1997 to 2022 were retrospectively/prospectively collected (NCT05931718). RESULTS: Overall, 33% patients required transfusions with a response rate of 83% and eight transfusion reactions (7%), none hemolytic. Alloantibodies were detected in 19% of patients, being associated with higher transfusion burden (p = 0.01), lower Hb increase post-transfusion (p = 0.05), and transfusion reactions (p = 0.04). Along decades, the rate of RBC transfusions decreased from 53% to 20% and that of alloimmunization dropped from 30% to 6% likely due to the adoption of prestorage leukoreduction, the use of more restrictive Hb thresholds, and the implementation of molecular typing. CONCLUSIONS: Severe symptomatic AIHA may be safely transfused provided appropriate matching of patients and donors.

A real-life evaluation of two platelet cross-matching programmes for the treatment of patients refractory to platelet transfusions.

BACKGROUND AND OBJECTIVES: Strategies for overcoming alloimmune refractoriness to random donor platelets are based on the use of compatible platelets selected from large panels of HLA-typed donors or cross-matching (XM). The aim of this study was to review the effectiveness of a platelet XM programme for treating refractory haematological patients at Milan's Policlinico Hospital (PHM) 2002-2014 and Spedali Civili in Brescia (SCB) 2013-2016. MATERIALS AND METHODS: A commercially available solid-phase antibody detection system was used for platelet antibody detection and XM. Forty-nine alloimmune refractory patients at PHM and 13 at SCB, respectively, received a median [IQR] of 12 [6-13] and 18 [13-15] XM compatible platelet transfusions after the detection of refractoriness. The absolute increases in post-transfusion platelet counts obtained using random, and XM platelets were retrieved from the patients' hospital records. RESULTS: The critical review at SCB showed that the median [IQR] 1 h post-transfusion increase in platelet counts was 3 × 109 /L [1-5] after 47/47 random platelet transfusions, and 10 × 109 /L [2-25] after 325/326 XM compatible platelet transfusions. The documentation concerning the outcomes of XM platelet transfusions at PHM was incomplete, and so the findings of the review were inconclusive. CONCLUSION: This retrospective analysis confirmed the effectiveness of the XM programme at SCB, but revealed defective data collection and retrieval methods at PHM, thus underlining the importance of such methods. The literature review accompanying this retrospective analysis identified a recently described algorithm for ensuring platelet support in refractory patients that optimally integrates the combined use of XM and HLA typing.

Clinical heterogeneity and predictors of outcome in primary autoimmune hemolytic anemia: a GIMEMA study of 308 patients.

The clinical outcome, response to treatment, and occurrence of acute complications were retrospectively investigated in 308 primary autoimmune hemolytic anemia (AIHA) cases and correlated with serological characteristics and severity of anemia at onset. Patients had been followed up for a median of 33 months (range 12-372); 60% were warm AIHA, 27% cold hemagglutinin disease, 8% mixed, and 5% atypical (mostly direct antiglobulin test negative). The latter 2 categories more frequently showed a severe onset (hemoglobin [Hb] levels ≤6 g/dL) along with reticulocytopenia. The majority of warm AIHA patients received first-line steroid therapy only, whereas patients with mixed and atypical forms were more frequently treated with 2 or more therapy lines, including splenectomy, immunosuppressants, and rituximab. The cumulative incidence of relapse was increased in more severe cases (hazard ratio 3.08; 95% confidence interval, 1.44-6.57 for Hb ≤6 g/dL; P < .001). Thrombotic events were associated with Hb levels ≤6 g/dL at onset, intravascular hemolysis, and previous splenectomy. Predictors of a fatal outcome were severe infections, particularly in splenectomized cases, acute renal failure, Evans syndrome, and multitreatment (4 or more lines). The identification of severe and potentially fatal AIHA in a largely heterogeneous disease requires particular experienced attention by clinicians.

Identification of six new RHCE variant alleles in individuals of diverse racial origin.

BACKGROUND: The introduction of molecular methods into routine blood typing is prompting the identification of new blood group alleles. Discrepancies between the results of genotyping and serology or chance events uncovered during genotyping prompted additional investigations, which revealed six new RHCE variant alleles. STUDY DESIGN AND METHODS: Samples from eight blood donors, two patients (one prenatal), and a patient's relative, all of diverse racial origin, were analyzed by standard serology methods, targeted genotyping arrays, DNA sequencing, and allele-specific polymerase chain reaction. RESULTS: Six new RHCE alleles were identified, namely, RHCE*cE84A, RHCE*ce202G, RHCE*ce307T, RHCE*Ce377G, RHCE*ce697G,712G,733G,744C, and RHCE*Ce733G. CONCLUSION: While implementation of new assays in commercial genotyping platforms to detect the polymorphisms reported here may not be justified given their apparent rarity, software interpretative algorithms may benefit from the identification of new alleles for a more accurate determination of genotypes and prediction of phenotypes.

HEA BeadChip™ technology in immunohematology.

Classic methods to determine human red blood cell (RBC) antigens are based on serologic testing. Thanks to increased knowledge of the molecular basis associated with many blood group antigens, it is currently possible to predict their presence or absence on the red cell membrane. Several molecular techniques have been developed to detect the most important allelic variations attributable to single nucleotide polymorphisms. The human erythrocyte antigen (HEA) BeadChip™ system manufactured by BioArray Solutions (Immucor, Warren, NJ) is one of the commercial DNA array platforms currently available to predict HEAs by DNA analysis. This technology provides a useful tool to increase the inventory of antigen-negative RBC units and prevent immunization of patients who require chronic transfusion by providing compatible RBC units based on matching by DNA testing.

Use of steroids in the management of low-risk myelodysplastic syndromes with autoimmune features.

BACKGROUND: The boundaries between myelodysplastic syndromes (MDS) and immune-mediated cytopenias are often difficult to establish and both conditions may benefit from immunosuppressive therapy. The optimal timing and doses of immunosuppressants are largely unknown. MATERIALS AND METHODS: We systematically evaluated a retrospective cohort of 79 patients with low-risk MDS tested for anti-erythrocyte or anti-platelet autoantibodies to assess their frequency and the efficacy of immunosuppression, particularly with steroids. RESULTS: We found autoantibody positivity in 43% of cases and overt autoimmune diseases in 18%, including autoimmune hemolytic anemia, immune thromboctyopenia, and Evans syndrome. Steroid treatment improved cytopenia in about half of patients, with 26% achieving a complete recovery lasting for a median of 12 months. Better responses were observed in anemic patients with anti-erythrocyte autoantibodies than in those with anti-platelet autoantibodies, and the combination with recombinant erythropoietin (7/10) had a possible synergistic effect. Steroid doses were heterogeneous depending on the clinical intent (i.e., anti-inflammatory, immunosuppressive, anabolizing). Patients treated with a dose of 1 mg/kg day of prednisone for overt autoimmune cytopenia showed high rates of complete responses (60%). DISCUSSION: This observation suggests a trial with a short course (2-3 weeks) of standard steroid doses to ascertain efficacy and properly silence the autoimmune pathogenic mechanism. Steroid-related adverse events (16% of cases) should be monitored carefully in this elderly, frail population. In conclusion, features of autoimmunity are present in more than two-thirds of low-risk MDS patients and a trial with prednisone 0.5-1 mg/kg day for 2-3 weeks, with proper monitoring of adverse events, may be useful to improve cytopenias in selected cases.

Low-Risk Myelodysplastic Syndrome Revisited: Morphological, Autoimmune, and Molecular Features as Predictors of Outcome in a Single Center Experience.

Low-risk myelodysplastic syndromes (LR-MDS) are a very heterogeneous disease, with extremely variable clinical features and outcome. Therapeutic strategies are still limited and mainly consist of erythropoiesis-stimulating agents (ESAs) and transfusion support. The contribution of molecular lesions and of autoimmune phenomena to pathogenesis and clinical course, including leukemic evolution, is a field of open investigation. We analyzed data from a cohort of 226 patients with LR-MDS followed at our center in the last 20 years, focusing on morphological, immunological (antiplatelets and anti-erythrocyte autoantibodies, anti-erythroblast antibodies), and molecular features. Hypoplastic bone marrow was found in 7% of the cases correlating with younger age, deeper cytopenia, lower dysplasia, and worse response to ESAs. A marker of autoimmunity was observed in 46% of the tested cases, who were younger, were less frequent dysplastic changes, and responded better to ESAs and steroids. Finally, 68% of the tested cases displayed at least one somatic mutation, most commonly SF3B1, TET2, ASXL1, and SRSF2, associated with older age, presence of neutropenia, and lower response to ESAs. Leukemic evolution (2.2%) was associated with presence of somatic mutations, and survival was favorably related to response to ESAs and transfusion independence. Overall, granular evaluation and re-evaluation are pivotal in LR-MDS patients to optimize clinical management.

ABO antibody titres: a multisite comparative study of equivalency and reproducibility for automated solid-phase and haemagglutination titration, and manual dilution with gel column agglutination technology.

BACKGROUND: ABO antibody titres are important in many clinical decisions; however, much variability is observed in titre results. For reliable and reproducible titre results, automated ABO titration methods have been developed. In this 10-site study, we evaluated the equivalency of the automated ABO titration assays on the Galileo NEO, a fully automated blood bank analyzer (Immucor, Inc.) to manual titration with gel Column Agglutination Technology (CAT), as well as the reproducibility of both methods. MATERIALS AND METHODS: Ten different locations participated in this study. The equivalency study included 70 random samples at each site. The reproducibility study tested the same blinded 30-sample panel at each study site. Anti-A and anti-B IgM and IgG antibody titres were tested with both the automated and manual methods; additionally, dithiothreitol (DTT) treatment was used to inactivate IgM antibodies in the manual CAT method. RESULTS: The equivalency between CAT manual method and Galileo NEO automated titres at each site ranged from 38 to 88%; equivalency for each isotype was 66.2% for IgM, 60.6% for IgG, and 88.5% for DTT-treated IgG. The reproducibility study evaluated the titre variation of each sample obtained from the 10 sites. The average titre ranges (in doubling dilutions) for the automated and manual methods, respectively, were 2.15±1.0 and 4.03±1.8 for IgM, and 1.53±0.7 and 4.10±1.9 for IgG; for the manual DTT-treated IgG, the average titre range was 3.45±1.8 doubling dilutions. DISCUSSION: The results demonstrated that the Galileo NEO automated and manual CAT ABO titres are not equivalent. However, the study also demonstrated that titre reproducibility is enhanced with the Galileo NEO automated ABO titration assays relative to the manual CAT ABO titration method. Therefore, to improve management of patients receiving care across multiple institutions, our study supports the use of automated ABO titration.

Autoimmune Hemolytic Anemia as a Complication of Congenital Anemias. A Case Series and Review of the Literature.

Congenital anemias may be complicated by immune-mediated hemolytic crisis. Alloantibodies are usually seen in chronically transfused patients, and autoantibodies have also been described, although they are rarely associated with overt autoimmune hemolytic anemia (AIHA), a serious and potentially life-threatening complication. Given the lack of data on the AIHA diagnosis and management in congenital anemias, we retrospectively evaluated all clinically relevant AIHA cases occurring at a referral center for AIHA, hemoglobinopathies, and chronic hemolytic anemias, focusing on clinical management and outcome. In our cohort, AIHA had a prevalence of 1% (14/1410 patients). The majority were warm AIHA. Possible triggers were recent transfusion, infection, pregnancy, and surgery. All the patients received steroid therapy as the first line, and about 25% required further treatment, including rituximab, azathioprine, intravenous immunoglobulins, and cyclophosphamide. Transfusion support was required in 57% of the patients with non-transfusion-dependent anemia, and recombinant human erythropoietin was safely administered in one third of the patients. AIHA in congenital anemias may be challenging both from a diagnostic and a therapeutic point of view. A proper evaluation of hemolytic markers, bone marrow compensation, and assessment of the direct antiglobulin test is mandatory.

No changes of parameters nor coagulation activation in healthy subjects vaccinated for SARS-Cov-2.

Background: Recent reports of thrombotic events after SARS-Cov-2 vaccination raised concern. However, modifications of the most common coagulation parameters after vaccination are unknown. Aims: We measured parameters of coagulation including (i) basic coagulation tests, (ii) procedures aimed to assess the ex-vivo potential capacity to generate thrombin and (iii) in vivo thrombin activity. We also assessed anti-platelet factor 4 (aPF4) with two methods. Design: Laboratory measurements were performed for a cohort of subjects (n = 30) before (baseline) and after (7 and 21days after first dose, and 14days after second dose) SARS-Cov-2 vaccination. Results: All subjects received the Pfizer-BioNTech vaccine, and none developed symptomatic thrombotic events during the study period. None of the parameters showed clinically relevant variations at different time-points before and after vaccination. Only platelet count showed a slight increase, and F1.2 and the thrombin generation parameters ETP and ETP-TM ratio, showed a small decline, at the last time-point after vaccination when compared to baseline. aPF4 was negative in all the subjects, except two, who were positive (one with the chemiluminescent and the other with the ELISA assay). Conclusions: The study shows no modifications of the coagulation parameters nor the presence of biochemical signs of coagulation activation following the administration of the Pfizer-BioNTech vaccine.

Evaluation of red blood cell and platelet antigen genotyping platforms (ID CORE XT/ID HPA XT) in routine clinical practice.

BACKGROUND: High-throughput genotyping platforms enable simultaneous analysis of multiple polymorphisms for blood group typing. BLOODchip® ID is a genotyping platform based on Luminex® xMAP technology for simultaneous determination of 37 red blood cell (RBC) antigens (ID CORE XT) and 18 human platelet antigens (HPA) (ID HPA XT) using the BIDS XT software. MATERIALS AND METHODS: In this international multicentre study, the performance of ID CORE XT and ID HPA XT, using the centres' current genotyping methods as the reference for comparison, and the usability and practicality of these systems, were evaluated under working laboratory conditions. DNA was extracted from whole blood in EDTA with Qiagen methodologies. Ninety-six previously phenotyped/genotyped samples were processed per assay: 87 testing samples plus five positive controls and four negative controls. RESULTS: Results were available for 519 samples: 258 with ID CORE XT and 261 with ID HPA XT. There were three "no calls" that were either caused by human error or resolved after repeating the test. Agreement between the tests and reference methods was 99.94% for ID CORE XT (9,540/9,546 antigens determined) and 100% for ID HPA XT (all 4,698 alleles determined). There were six discrepancies in antigen results in five RBC samples, four of which (in VS, N, S and Do(a)) could not be investigated due to lack of sufficient sample to perform additional tests and two of which (in S and C) were resolved in favour of ID CORE XT (100% accuracy). The total hands-on time was 28-41 minutes for a batch of 16 samples. Compared with the reference platforms, ID CORE XT and ID HPA XT were considered simpler to use and had shorter processing times. DISCUSSION: ID CORE XT and ID HPA XT genotyping platforms for RBC and platelet systems were accurate and user-friendly in working laboratory settings.

The Lombardy Rare Donor Programme.

BACKGROUND: In 2005, the government of Lombardy, an Italian region with an ethnically varied population of approximately 9.8 million inhabitants including 250,000 blood donors, founded the Lombardy Rare Donor Programme, a regional network of 15 blood transfusion departments coordinated by the Immunohaematology Reference Laboratory of the Ca' Granda Ospedale Maggiore Policlinico in Milan. During 2005 to 2012, Lombardy funded LORD-P with 14.1 million euros. MATERIALS AND METHODS: During 2005-2012 the Lombardy Rare Donor Programme members developed a registry of blood donors and a bank of red blood cell units with either rare blood group phenotypes or IgA deficiency. To do this, the Immunohaematology Reference Laboratory performed extensive serological and molecular red blood cell typing in 59,738 group O or A, Rh CCDee, ccdee, ccDEE, ccDee, K- or k- donors aged 18-55 with a record of two or more blood donations, including both Caucasians and ethnic minorities. In parallel, the Immunohaematology Reference Laboratory implemented a 24/7 service of consultation, testing and distribution of rare units for anticipated or emergent transfusion needs in patients developing complex red blood cell alloimmunisation and lacking local compatible red blood cell or showing IgA deficiency. RESULTS: Red blood cell typing identified 8,747, 538 and 33 donors rare for a combination of common antigens, negative for high-frequency antigens and with a rare Rh phenotype, respectively. In June 2012, the Lombardy Rare Donor Programme frozen inventory included 1,157 red blood cell units. From March 2010 to June 2012 one IgA-deficient donor was detected among 1,941 screened donors and IgA deficiency was confirmed in four previously identified donors. From 2005 to June 2012, the Immunohaematology Reference Laboratory provided 281 complex red blood cell alloimmunisation consultations and distributed 8,008 Lombardy Rare Donor Programme red blood cell units within and outside the region, which were transfused to 2,365 patients with no untoward effects. DISCUSSION: Lombardy Rare Donor Programme, which recently joined the ISBT Working Party on Rare Donors, contributed to increase blood transfusion safety and efficacy inside and outside Lombardy.

Comparison of traditional methods and mitogen-stimulated direct antiglobulin test for detection of anti-red blood cell autoimmunity.

The diagnosis of autoimmune hemolytic anemia (AIHA) is based on a positive direct antiglobulin test (DAT), which is performed using various methods with different sensitivities. Recently, mitogen-stimulated (MS)-DAT was suggested to be able to identify latent anti-erythrocyte autoimmunity. Traditional methods (tube, microcolumn, and solid phase) and MS-DAT were compared in 54 consecutive cases of suspected AIHA, 28 idiopathic AIHA in clinical remission, and 12 difficult-to-diagnose cases of DAT-negative AIHA, and the results (all cases) were correlated with hematologic and hemolytic parameters. DAT tube was confirmed as the gold standard to diagnose AIHA since almost all positive cases showed hemolytic anemia and positive eluates; 10 out of 26 tube-negative cases were positive on microcolumn and solid phase antiglobulin tests, and 22 out of 26 using MS-DAT, although only half of them showed clear signs of hemolysis. Mitogen stimulation increased the amount of IgG bound to red blood cells in all groups; moreover, MS-DAT was the only positive test in 10 cases of AIHA, and mitogen stimulation facilitated the identification of autoantibody specificity in culture supernatants. We conclude that a battery of tests rather than a single test is useful for the diagnosis of AIHA, including MS-DAT as an additional test for selected cases, although the results have to be cautiously interpreted based on the overall clinical context.