Advances in Human Leukocyte Antigen Testing Technologies and Management Strategies for Platelet Transfusion Refractoriness.

CONTEXT.­: The blood bank is often consulted for transfusion support of patients with suspected platelet transfusion refractoriness (PTR). The workup is complex because testing includes specialized assays that are uncommonly ordered with limited availability. Add to this the variety of possible products-crossmatched platelets, human leukocyte antigen (HLA)-matched platelets, HLA antigen-negative platelets-and the approach to PTR can be overwhelming. Moreover, most literature on the subject is published in transfusion medicine journals aimed at transfusion medicine physicians and blood bank specialists in academic settings. Resources tailored to community hospital blood banks are lacking. OBJECTIVE.­: To provide pathologists who may not have subspecialized training in transfusion medicine and who direct blood banks algorithmic workflows based on clinical scenario and test availability to provide appropriate transfusion support for patients with PTR. DATA SOURCES.­: This review is a comprehensive overview of terminology, HLA testing procedures, interpretations, and practical recommendations for managing PTR in various scenarios based on expert opinion as well as relevant medical literature published from 2007 to 2022. CONCLUSIONS.­: Consultation on PTR is complicated and encompasses many clinical and laboratory aspects. The lack of guidelines derived from high-quality prospective studies poses challenges in the workup and management of PTR. Hindering the process further are limited test availability, unfamiliarity with the technical assays, and the various specialized platelet products. The clinical evaluation algorithm presented herein along with the workflow pathways offer pathologists user-friendly and best-practice guidelines with different options based on the clinical scenario and the tests available.

Comprehensive guide to managing a chronic automated red cell exchange program in sickle cell disease.

Sickle cell disease (SCD) is associated with significant morbidity and mortality, and limits both the quality and quantity of life. Transfusion therapy, specifically automated red cell exchange (aRCE), plays a key role in management of SCD and is beneficial for certain indications in the chronic, outpatient setting. The approach to maintain a successful chronic aRCE program for SCD is multifaceted. This review will highlight important considerations including indications for aRCE, patient selection, transfusion medicine pearls, vascular access needs, complications of therapy, aRCE prescription, and therapy optimization. Moreover, the importance of a multidisciplinary approach with frequent communication between the services involved cannot be overstated. Ultimately, the underlying goal of a chronic RCE program is to improve the quality of life and longevity of patients with SCD.

Economic implications of FDA platelet bacterial guidance compliance options: Comparison of single-step strategies.

BACKGROUND: Bloodborne pathogens pose a major safety risk in transfusion medicine. To mitigate the risk of bacterial contamination in platelet units, FDA issues updated guidance materials on various bacterial risk control strategies (BRCS). This analysis presents results of a budget impact model updated to include 5- and 7-day pathogen reduced (PR) and large volumed delayed sampling (LVDS) BRCS. STUDY DESIGN AND METHODS: Model base-case parameter inputs were based on scientific literature, a survey distributed to 27 US hospitals, and transfusion experts' opinion. The outputs include hospital budget and shelf-life impacts for 5- and 7-day LVDS, and 5- and 7-day PR units under three different scenarios: (1) 100% LVDS, (2) 100% PR, and (3) mix of 50% LVDS - and 50% PR. RESULTS: Total annual costs from the hospital perspective were highest for 100% LVDS platelets (US$2.325M) and lowest for 100% PR-7 units (US$2.170M). Net budget impact after offsetting annual costs by outpatient reimbursements was 5.5% lower for 5-day PR platelets as compared to 5-day LVDS (US$1.663 vs. US$1.760M). A mix of 7-day LVDS and 5-day PR platelets had net annual costs that were 1.3% lower than for 100% 7-day LVDS, but 1.3% higher than for 100% 5-day PR. 7-day PR platelets had the longest shelf life (4.63 days), while 5-day LVDS had the shortest (2.00 days). DISCUSSION: The model identifies opportunities to minimize transfusion center costs for 5- and 7-day platelets. Budget impact models such as this are important for understanding the financial implications of evolving FDA guidance and new platelet technologies.

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.

ABO maternal-child discordance: Evidence of variable allelic expression and considerations for investigation.

BACKGROUND: We report a case of apparent mother-child ABO group noninheritance. A Caucasian mother initially typed as group O and her infant group AB. Investigation ruled out preanalytical causes such as mislabeled samples and in vitro fertilization. MATERIALS AND METHODS: Red blood cells were characterized by routine serologic testing. Genomic data were analyzed by targeted polymerase chain reaction-restriction fragment length polymorphism and Sanger sequencing. Transferase structures were modeled using PyMOL molecular visualization software. RESULTS: Serologic testing initially demonstrated the mother was group O, father group AB, and infant group AB. Further testing of the maternal sample with anti-A,B demonstrated weak A expression. Molecular testing revealed the maternal sample had an ABO*O.01.01 allele in trans to an A allele, ABO*AW.29 (c.311T>A, p.Ile104Asn), determined by gene sequencing. The sample from the infant carried the same ABO*AW.29 allele in trans to a B allele, ABO*B.01. CONCLUSION: ABO genotyping revealed an A transferase encoded by ABO*AW.29, with apparent variable activity. Although A antigen expression is well known to be weak in newborns, it was robust on the red blood cells (RBCs) of the AB infant and undetectable with anti-A on the mother. Variable expression of weak subgroups may reflect competition or enhancement by a codominant allele, as well as glycan chain maturation on red cells. Previous examples in group AB mothers with Aweak infants suggested that the decreased expression is primarily due to glycan immaturity. To our knowledge, this is the first reported case of the ABO*AW.29 allele presenting with weak A expression in a group Aweak mother and robust A expression in a group AB infant, suggesting the in trans allele is an important factor in determining transferase activity and may override age-related effects.

Lack of persistent microchimerism in contemporary transfused trauma patients.

BACKGROUND: Following transfusion, donor white blood cells (WBCs) can persist long-term in the recipient, a phenomenon termed transfusion-associated microchimerism (TA-MC). Prior studies suggest TA-MC is limited to transfusion following traumatic injury, and is not prevented by leukoreduction. STUDY DESIGN AND METHODS: We conducted a prospective cohort study at a major trauma center to evaluate TA-MC following injury. Index samples were collected upon arrival, prior to transfusion. Follow-up samples were collected at intervals up to one year, and beyond for those testing positive for TA-MC. TA-MC was detected by real-time quantitative allele-specific polymerase chain reaction assays at the HLA-DR locus and several polymorphic insertion deletion sites screening for non-recipient alleles. RESULTS: A total of 378 trauma patients were enrolled (324 transfused cases and 54 non-transfused controls). Mean age was 42 ± 18 years, 74% were male, and 80% were injured by blunt mechanism. Mean Injury Severity Score was 20 ± 12. Among transfused patients, the median (interquartile range) number of red cell units transfused was 6 (3,12), and median time to first transfusion was 9 (0.8,45) hours. Only one case of long-term TA-MC was confirmed in our cohort. We detected short-term TA-MC in 6.5% of transfused subjects and 5.6% on non-transfused controls. CONCLUSIONS: In contrast to earlier studies, persistent TA-MC was not observed in our cohort of trauma subjects. Short-term TA-MC was detected, but at a lower frequency than previously observed, and rates were not significantly different than what was observed in non-transfused controls. The reduction in TA-MC occurrence may be attributable to changes in leukoreduction or other blood processing methods.

Phased implementation of pathogen-reduced platelets in a health system facilitates increased manufacturing at the blood center.

BACKGROUND: Pathogen reduction treatment (PRT) reduces the risk of transfusion-transmitted infections from established and emerging organisms. Manufacturing, however, is complex. In our university health system, we phased in pathogen-reduced platelets (PR PLTs) by patient population. We then assessed the implementation strategy and investigated factors in the supply chain that prevented us from meeting the goal of providing greater than 90% PR PLTs within 6 months. STUDY DESIGN AND METHODS: In Phase 1, PR PLTs were provided in the outpatient cancer center. Phase 2 added inpatients undergoing bone marrow transplantation, and Phase 3 included all patients. In Phase 4, the blood center implemented manufacturing optimization strategies. Product supply and usage during the first 23 months after implementation were evaluated. Investigation of the supply chain included analysis of (1) the number of in-state hospitals receiving PR PLTs; (2) the fraction of products eligible for PRT before and after manufacturing improvements. RESULTS: During Phases 1 and 2, PR products comprised 44% and 53% of PLTs transfused in the phased-in areas. At 6 months, 41% of PLTs were PR, and at 23 months, 92%. The fraction of PR PLTs transfused in our system correlated logarithmically with the number of in-state hospitals receiving them (R2 = 0.71) and the number of PR PLTs sold to those hospitals (R2 = 0.80). CONCLUSION: Phased implementation is a practical and ethical way to introduce PR PLTs in a health system and facilitates scalability at the blood center. Widespread availability of PR products may require collective action and can be increased by optimization strategies during manufacturing.

Transfusion Support for ABO-Incompatible Progenitor Cell Transplantation.

ABO-incompatible transplants comprise up to 50% of allogeneic progenitor cell transplants. Major, minor and bidirectional ABO-incompatible transplants each have unique complications that can occur, including hemolysis at the time of progenitor cell infusion, hemolysis during donor engraftment, passenger lymphocyte syndrome, delayed red blood cell engraftment, and pure red cell aplasia. Appropriate transfusion support during the different phases of the allogeneic progenitor cell transplant process is an important part of ABO-incompatible transplantation.

Methods for the selection of platelet products for alloimmune-refractory patients.

The ability to efficiently and accurately diagnose the cause(s) of platelet (PLT) refractoriness is paramount in providing effective PLT products for transfusion. Recent advances in methods for detecting and identifying alloantibodies against human leukocyte antigens (HLAs) and human PLT antigens, combined with accurate molecular techniques for HLA typing, have provided a framework for the development of clinical algorithms to support such patients. Alloantibodies may be detected and/or identified by several methods, including complement-dependent cytotoxicity, enzyme-linked immunosorbent assays (ELISA), and microbead-based assays using Luminex or flow cytometry. The primary difference in these assays is the sensitivity of detection and the range of antibody specificities that may be reliably identified. Direct PLT cross-matching to identify compatible PLTs can be accomplished by several methods, including solid-phase red cell adherence, modified antigen capture ELISA, and flow cytometry. A survey of blood centers and laboratories providing transfusion support has identified the heterogeneity of testing options available, areas of concern and need for improvement, and common obstacles in providing appropriate and timely support to immune-refractory PLT patients. Depending on the testing methods and the pool of HLA-typed PLT donors available, there are numerous options for developing suitable algorithms to provide effective support to immune-refractory PLT patients.

Transfusion-related acute lung injury.

Transfusion-related acute lung injury is a clinical syndrome that occurs within 6 hours of transfusion. It is the leading cause of transfusion-related mortality. It presents with shortness of breath, acute pulmonary edema, fever, hypotension, or hypertension followed by hypotension. Treatment consists of respiratory support and fluid administration to support blood pressure. A majority of cases are associated with antibodies to white blood cells in the blood donor. Blood centers in the United States are currently taking measures to reduce the risk of transfusion-related acute lung injury from blood components.

Donor antibodies to HNA-3a implicated in TRALI reactions prime neutrophils and cause PMN-mediated damage to human pulmonary microvascular endothelial cells in a two-event in vitro model.

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. Antibodies to HNA-3a are commonly implicated in TRALI. We hypothesized that HNA-3a antibodies prime neutrophils (PMNs) and cause PMN-mediated cytotoxicity through a two-event pathogenesis. Isolated HNA-3a+ or HNA-3a- PMNs were incubated with plasma containing HNA-3a antibodies implicated in TRALI, and their ability to prime the oxidase was measured. Human pulmonary microvascular endothelial cells (HMVECs) were activated with endotoxin or buffer, HNA-3a+ or HNA-3a- PMNs were added, and the coculture was incubated with plasma+/-antibodies to HNA-3a. PMN-mediated damage was measured by counting viable HMVECs/mm2. Plasma containing HNA-3a antibodies primed the fMLP-activated respiratory burst of HNA-3a+, but not HNA-3a-, PMNs and elicited PMN-mediated damage of LPS-activated HMVECs when HNA-3a+, but not HNA-3a-, PMNs were used. Thus, antibodies to HNA-3a primed PMNs and caused PMN-mediated HMVEC cytotoxicity in a two-event model identical to biologic response modifiers implicated in TRALI.

Transfusion-related acute lung injury: definition and review.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is now the leading cause of transfusion-associated mortality, even though it is probably still underdiagnosed and underreported. NATIONAL HEART, LUNG, AND BLOOD INSTITUTE ACTION: The National Heart, Lung, and Blood Institute convened a working group to identify areas of research needed in TRALI. The working group identified the immediate need for a common definition and thus developed the clinical definition in this report. MAJOR CONCEPTS IN THE DEFINITION: The major concept is that TRALI is defined as new acute lung injury occurring during or within 6 hrs after a transfusion, with a clear temporal relationship to the transfusion. Also, another important concept is that acute lung injury temporally associated with multiple transfusions can be TRALI, because each unit of blood or blood component can carry one or more of the possible causative agents: antileukocyte antibody, biologically active substances, and other yet unidentified agents. RECOMMENDATION: Using the definition in this report, clinicians can diagnose and report TRALI cases to the blood bank; importantly, researchers can use this definition to determine incidence, pathophysiology, and strategies to prevent this leading cause of transfusion-associated mortality.

Leukocyte antibodies and biologically active mediators in the pathogenesis of transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) is a clinical constellation of signs and symptoms associated with transfusion. In severe cases, the most prominent feature is acute onset of pulmonary edema. Two mechanisms have been advanced to explain pulmonary injury in this syndrome. One mechanism involves the presence of antibodies to white blood cells, usually in a transfused blood component. Interaction of antibodies, with white blood cells in the transfusion recipient, is hypothesized to cause cellular activation with release of cytokines resulting in pulmonary vascular endothelial damage and exudation of fluid across the pulmonary basement membrane. In the biologically active mediator mechanism, two events are hypothesized to cause TRALI. In the first event, polymorphonuclear cells become primed and pulmonary vascular endothelium becomes activated secondary to the production of biologically active mediators, as a result of physiologic stress. The second event is the infusion of biologically active mediators in a stored cellular blood product. The second event causes release of cellular activators with subsequent endothelial damage and exudation of fluid into the pulmonary alveoli.

Pulmonary injury from transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) can be a life-threatening complication of transfusion. In its severe form, it is clinically indistinguishable from acute respiratory distress syndrome. Symptoms typically begin within 4 hours of transfusion. TRALI has been reported after transfusion of all plasma-containing blood components. TRALI is associated with antibodies to white blood cells and biologically active lipids in trans-fused blood components.

TRALI: correlation of antigen-antibody and monocyte activation in donor-recipient pairs.

BACKGROUND: TRALI may be a severe reaction associated with transfusion of plasma-containing blood components. TRALI has usually been associated with antibodies against granulocytes and HLA class I antigens, but more recently with antibodies against HLA class II and monocytes. TRALI cases were investigated to determine correlation between antigen and antibody. Additionally, activation of monocytes by TRALI serums was studied. STUDY DESIGN AND METHODS: Sixteen cases of TRALI were investigated. All patients were typed for HLA antigens. Implicated donors were screened for HLA antigens and antibodies against granulocytes and monocytes. In 6 cases, recipient monocyte activation was measured in vitro after incubation with TRALI and control serums. In four cases, monocyte activation was measured after incubation of TRALI serums against a panel of monocytes of known HLA antigen type. RESULTS: In 14 of the 16 cases (87.5%), antigen-antibody correlation was identified. TRALI monocytes, incubated with implicated TRALI serum (n = 6), expressed significantly greater cytokine and tissue factor (p < 0.05, repeated-measures ANOVA) than controls. Panel monocytes incubated with TRALI serum showed increased expression of cytokine and/or tissue factor when corresponding antigen was present. CONCLUSION: In most cases of TRALI, a correlation between antigen and antibody can be identified. Activation of monocytes and their subsequent release of cytokines may play a role in the pathogenesis of TRALI.

Early diagnosis and successful treatment of a patient with transfusion-associated GVHD with autologous peripheral blood progenitor cell transplantation.

BACKGROUND: Transfusion-associated GVHD (TA-GVHD) is an uncommon complication of blood transfusion. Diagnosis of TA-GVHD is difficult, and it is usually rapidly fatal. There are few documented sur- vivors of TA-GVHD. CASE REPORT: A 61-year-old woman with chronic lymphocytic leukemia (CLL) was treated with fludarabine followed by combination chemotherapy and high-dose radioimmunotherapy and peripheral blood progenitor cell (PBPC) rescue. She was transfused with nonirradiated blood components at an outside hospital and presented 10 days later with rash, elevated liver enzymes, and progressive pancytopenia. Skin biopsy was consistent with GVHD, and HLA typing of lymphocytes from the patient demonstrated mixed chimerism. The patient was treated with solumedrol and cyclosporin A, followed by high-dose cyclophosphamide and antithymocyte globulin and autologous PBPC infusion. She had rapid engraftment, resolution of skin rash, and normalization of liver function abnormalities. She is in good health with normal blood counts and no evidence of CLL 34 months after transplantation. CONCLUSION: TA-GVHD occurs in the setting of an immunocompromised recipient receiving nonirradiated blood components. A typical presentation includes skin rash, liver function abnormalities, and pancytopenia. Demonstration of mixed chimerism by HLA typing facilitated diagnosis in this patient. High-dose immunosuppression, facilitated by the availability of autologous PBPCs, resulted in a successful outcome.

Transfusion-related acute lung injury: report of a clinical look-back investigation.

CONTEXT: Transfusion-related acute lung injury (TRALI) is a syndrome that includes dyspnea, hypotension, bilateral pulmonary edema, and fever. TRALI is the third leading cause of transfusion-related mortality, but it is probably underdiagnosed and underreported. OBJECTIVE: To determine if blood products from a frequent plasma donor, whose blood product was implicated in a fatal case of TRALI, caused symptoms of TRALI in other recipients of her plasma. DESIGN, SETTING, AND PARTICIPANTS: Retrospective chart review (conducted from November 2000 through April 2001) of 50 patients who received blood components within 2 years (October 1998 through October 2000) from a donor linked to a transfusion-related fatality. MAIN OUTCOME MEASURE: Occurrence of mild/moderate (dyspnea with fever, chills, hypotension, and/or hypoxemia) or severe (acute pulmonary edema or need for mechanical ventilation) reaction associated with transfusion. RESULTS: Superimposed illness prevented assessment of TRALI in 14 patients. Of the 36 patient charts that could be reviewed, 7 mild/moderate reactions were reported in 6 patients (16.7%) and 8 severe reactions were reported in 8 patients (22.2%). Of 5 patients who received multiple transfusions from the same donor, 2 experienced 2 reactions: one had 2 mild/moderate reactions and the other had both a mild/moderate and a severe reaction. While 5 of the 7 mild/moderate reactions were reported to the hospital transfusion service, only 2 of the 8 severe reactions were reported. Only 2 reactions (1 mild/moderate and 1 severe) were reported to the regional blood collection facility. CONCLUSIONS: TRALI was frequently underdiagnosed and underreported in recipients of blood products from a donor whose blood products may have caused TRALI in several transfusion recipients. Clinical education and awareness of this often-overlooked diagnosis are imperative for appropriate prevention and treatment.