Warm autoimmune hemolytic anemia with anti-Jka specificity following babesiosis masquerading as a delayed hemolytic transfusion reaction.

BACKGROUND: Warm autoimmune hemolytic anemia (WAIHA) is characterized by the development of autoantibodies that react with red blood cells (RBCs) optimally at physiologic temperature, classically resulting in a positive direct antiglobulin test (DAT) for IgG and a panreactive eluate. Babesiosis has been described as a potentiator of WAIHA, and all cases have shown classic blood bank findings. Only rare reports have described autoantibodies, both secondary to babesiosis and overall, with specificity for Kidd antigens. METHODS: Antibody detection and identification were performed using IgG-specific column agglutination technology. Jka antigen phenotyping was assessed using monoclonal reagents and genotypic analysis was performed at an immunohematology reference laboratory. DATs were performed via standard tube methods. The elution was performed using the ELUclear glycine acid red cell elution kit. RESULTS: We report a case of WAIHA induced by Babesia microti infection with an autoantibody with Jka specificity, originally believed to be a delayed hemolytic transfusion reaction, given the detection of an RBC antibody in close proximity to numerous RBC transfusions. Determination of autoantibody status with anti-Jka -like reactivity was only confirmed after Kidd antigen genotyping predicted expression of the Jka antigen. DISCUSSION: Healthcare providers should be cognizant of the potential for babesiosis-induced WAIHA, particularly in individuals who continue to hemolyze despite undetectable parasitemia. Furthermore, this case highlights the possibility for warm autoantibodies to demonstrate Kidd antigen specificity. Though Kidd antigen variants are rare, antigen genotyping may be beneficial, particularly in the context of recent RBC transfusions, which typically preclude accurate serological phenotypic assessment.

Alloimmunization following antigen-negative red blood cell transfusion.

BACKGROUND: Red blood cell (RBC) alloimmunization can occur secondary to transfusion or pregnancy. It is observed most frequently among patients with hemoglobinopathies and myeloid neoplasms. Although previous antigen exposure is generally required for alloimmunization, some alloantibodies may develop naturally without prior exposure. Other alloantibodies may become evanescent, only to reemerge at a detectable titer following a stimulatory event. In a minute fraction of cases, 'non-naturally occurring' alloantibodies may appear without a known antigenic stimulus. METHODS AND MATERIALS: All testing (antibody detection tests and identification, antigen phenotyping, and crossmatching) was performed using the same method and reagents, but occurred at two hospitals within the Yale New Haven Hospital delivery network, and was performed by technologists utilizing different instruments and reagent lots. RESULTS: We present two cases of seemingly de novo alloimmunization (anti-E and anti-K), and one case of re-emergence of a known, previously evanescent alloantibody (anti-K) following transfusion of RBCs that were antigen-negative for the corresponding antibodies. CONCLUSION: While the exact mechanism underlying the development and/or re-emergence of RBC alloantibodies in the absence of antigenic stimulation remains unclear, these cases highlight this unusual phenomenon, underscoring the general immunogenicity, as well as the potential consequences, of RBC transfusion and reiterates the importance of concluding an alloantibody specificity, even in the absence of known transfusion of RBCs with a particular antigen.

Passive transfer of alloantibodies through breast milk as a mediator of hemolytic anemia.

BACKGROUND: Hemolytic disease of the fetus and newborn (HDFN) is characterized by destruction of fetal/neonatal red blood cells (RBCs) secondary to maternally derived antibodies, which are typically thought to be passively acquired via placental transfer. Few cases have examined the possibility of HDFN mediated by maternal antibodies passively transferred via breast milk. METHODS: We describe two cases of persistent HDFN in infants potentially mediated by passively acquired antibodies via maternal breast milk. We discuss supporting and refuting evidence that may account for this possibility and describe testing methodology illustrating how maternal alloantibodies can be detected in breast milk. RESULTS: In both cases, anti-D antibodies were detected in maternal breast milk. One patient experienced a significant decrease in anti-D plasma titer from 64 to 4 dilutions following 2 weeks of breastfeeding cessation. The other patient experienced a resolution of anemia without breastfeeding cessation. CONCLUSION: There is a paucity of data regarding the lifespan of passively acquired RBC antibodies in neonatal circulation, with significant variation noted between passively acquired IgG based on studies utilizing intravenous immunoglobulin compared to studies of maternally-acquired antiviral IgG antibodies. While our data do not definitively implicate passive transfer of alloantibodies in breast milk as a mediator of HDFN, they do illustrate the need for further investigation into the mechanisms and kinetics of passively acquired antibodies in neonatal circulation.

Immunity in the balance: Fatal disseminated adenovirus infection in a patient undergoing plasma exchange and immunosuppressive chemotherapy for anti-glomerular basement membrane disease.

Anti-glomerular basement membrane (anti-GBM) disease (formerly known as Goodpasture's syndrome) is a rare autoinflammatory condition that affects the renal and/or pulmonary capillaries. The standard therapeutic regimen for anti-GBM disease involves therapeutic plasma exchange (TPE), cyclophosphamide, and corticosteroids to rapidly remove and inhibit autoantibody production and reduce organ inflammation. Herein we report an 82-year-old female who developed anti-GBM disease but expired despite therapy, secondary to multi-organ failure in the setting of disseminated adenovirus disease. We discuss the utility and potential adverse effect of daily TPE for a protracted course (ie, 10-14 days), the recommended TPE intensity in the 2023 American Society for Apheresis guidelines, updated from every-other-day TPE in the 2019 guidelines, despite no new data. We also highlight the potential for unusual infections to occur in these patients due to the profound immunosuppression, and discuss the importance of balancing immunosuppression to treat the disease with close surveillance of any potential opportunistic infections.

Botulism mimicking Guillain-Barre syndrome: The question of plasma exchange in an unusual case of acute paralysis.

Guillain-Barré syndrome (GBS) is an immune-mediated polyradiculoneuropathy and the most common cause of acute flaccid paralysis worldwide. GBS classically presents with acute, progressive, ascending weakness, reduced to absent reflexes, and albuminocytological dissociation on cerebrospinal fluid (CSF) analysis. Botulism is a neurotoxin-mediated acute descending flaccid paralysis with cranial nerve palsies and dysautonomia. Botulism in adults is caused by ingestion/inhalation of botulinum toxin or wound infection with Clostridium botulinum. Both GBS and botulism can rapidly precipitate respiratory failure; thus, prompt diagnosis and treatment are crucial to mitigate poor outcomes. Herein, we describe a case of botulism initially diagnosed as GBS given classic laboratory features, and describe the importance of careful consideration of the most appropriate therapeutic modalities in cases of acute flaccid paralysis, particularly regarding empiric administration of botulinum antitoxin and use of intravenous immune globulin in lieu of plasma exchange for potential GBS to prevent removal of antitoxin.

Blood conservation strategies at United States hospitals during the COVID-19 pandemic: Findings from a multi-institutional analysis - International Society of Blood Transfusion survey.

BACKGROUND: Due to the coronavirus disease 2019 (COVID-19) pandemic, the transfusion medicine community has experienced unprecedented blood supply shortages since March 2020. As such, numerous changes to everyday practice have occurred with a specific emphasis on blood conservation. We sought to determine the strategies used to mitigate blood shortages and promote blood conservation during the pandemic. METHODS: An anonymous, 37-question survey was developed using Research Electronic Data Capture and distributed via e-mail to transfusion medicine specialists across the US obtained via publicly available databases. RESULTS: Amongst surveyed [41.1% response rate (51/124 institutions)], 98.0% experienced a product shortage, with the greatest number reporting red blood cell (RBC) shortages (92.0%). This led to 35.3% of institutions altering the composition and/or number of blood product suppliers, including a 100% increase in the number of institutions acquiring blood from organizations that connect hospital transfusion services with blood collection centers (e.g., Blood Buy) compared to before March 2020. Prospective triaging of blood products was the most common blood conservation strategy (68.1%), though 35.4% altered their RBC exchange or transfusion program for patients receiving chronic RBC transfusion/exchange. As a result of these changes, 78.6% of institutions reported that these changes resulted in a reduction in blood product usage, and 38.1% reported a decrease in product wastage. CONCLUSIONS: Most hospitals experienced the effects of the supply shortage, and many of them implemented blood conserving measures. Conservation strategies were associated with decreased blood utilization and waste, and future studies could evaluate whether these changes persist.

Development of a prognostic model for mortality in COVID-19 infection using machine learning.

Coronavirus disease 2019 (COVID-19) is a novel disease resulting from infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has quickly risen since the beginning of 2020 to become a global pandemic. As a result of the rapid growth of COVID-19, hospitals are tasked with managing an increasing volume of these cases with neither a known effective therapy, an existing vaccine, nor well-established guidelines for clinical management. The need for actionable knowledge amidst the COVID-19 pandemic is dire and yet, given the urgency of this illness and the speed with which the healthcare workforce must devise useful policies for its management, there is insufficient time to await the conclusions of detailed, controlled, prospective clinical research. Thus, we present a retrospective study evaluating laboratory data and mortality from patients with positive RT-PCR assay results for SARS-CoV-2. The objective of this study is to identify prognostic serum biomarkers in patients at greatest risk of mortality. To this end, we develop a machine learning model using five serum chemistry laboratory parameters (c-reactive protein, blood urea nitrogen, serum calcium, serum albumin, and lactic acid) from 398 patients (43 expired and 355 non-expired) for the prediction of death up to 48 h prior to patient expiration. The resulting support vector machine model achieved 91% sensitivity and 91% specificity (AUC 0.93) for predicting patient expiration status on held-out testing data. Finally, we examine the impact of each feature and feature combination in light of different model predictions, highlighting important patterns of laboratory values that impact outcomes in SARS-CoV-2 infection.

Management of Red Cell Alloimmunization in Pregnancy.

Rhesus immune globulin has resulted in a marked decrease in the prevalence of RhD alloimmunization in pregnancy; however, antibody formation to other red cell antigens continues to occur. Evaluation for the presence of anti-red cell antibodies should be routinely undertaken at the first prenatal visit. If anti-red cell antibodies are detected, consideration of a consultation or referral to a maternal-fetal medicine specialist with experience in the monitoring and treatment of these patients is warranted. Cell-free DNA can be used to determine fetal red cell antigen status to determine whether the pregnancy is at risk of complications from the red cell antibodies. First-time sensitized pregnancies are followed up with serial maternal titers, and, when indicated, serial Doppler assessment of the peak systolic velocity in the middle cerebral artery should be initiated by 16 weeks of gestation. When there is a history of an affected fetus or neonate, maternal titers are less predictive of fetal risk; if the fetus is antigen positive, serial peak systolic velocity in the middle cerebral artery measurements should be initiated by 15 weeks of gestation because intraperitoneal intrauterine blood transfusions can be used at this gestation if needed. The mainstay of fetal therapy involves intrauterine transfusion through ultrasound-directed puncture of the umbilical cord with the direct intravascular injection of red cells. A perinatal survival rate exceeding 95% can be expected at experienced centers. Neonatal phototherapy and "top-up" transfusions attributable to suppressed reticulocytosis often are still required for therapy after delivery.

Assessing Recommendations for Determining Fetal Risk in Alloimmunized Pregnancies in the United States: Is It Time to Update a Decades-Old Practice?

The current recommended testing algorithm for assessing the alloimmunized pregnancy utilized by many obstetricians in the United States (US) fails to consider the most recent evidence, placing fetuses, and mothers at unnecessary risk of poor outcome or death. This narrative review of the current landscape of fetal red blood cell (RBC) antigen testing evaluates the history of hemolytic disease of the fetus and newborn (HDFN) and how its discovery has continued to influence practices in the US today. We compare current US-based HDFN practice guidelines with those in Europe. We also provide transfusion medicine and hematology perspectives and recommendations addressing the limitations of US practice, particularly regarding paternal RBC antigen testing, and discuss the most valuable alternatives based on decades of data and evidence-based recommendations from Europe.

Maternal red blood cell alloimmunization prevalence in the United States.

ABSTRACT: Hemolytic disease of fetus and newborn (HDFN) is a life-threatening disease mediated by maternal alloimmunization to red blood cell (RBC) antigens. Studies of maternal alloimmunization prevalence in the United States lack national data. This study describes prevalence and trends in alloimmunization in pregnancy in the United States. RBC antibodies (abs) were identified in a large, nationwide, commercial laboratory database from 2010 through 2021. The cohort comprised pregnancies for which the year of laboratory collection and patient's state of residence were available. Data were normalized based on US Centers for Disease Control and Prevention estimates of live births and weighted by year and US Census Division. Cochrane-Armitage tests assessed temporal trends of alloimmunization. Of 9 876 196 pregnancies, 147 262 (1.5%) screened positive for RBC abs, corresponding to an estimated prevalence of 1518 of 100 000 pregnancies. Of identified RBC abs, anti-D comprised 64.1% pregnancies (586/100 000). Prevalence of other high-risk RBC abs for HDFN included anti-K (68/100 000) and anti-c (29/100 000). Incidence of all 3 high-risk abs increased from 2010 to 2021 (all P < .001). Among almost 10 million pregnancies in the United States, comprising an estimated 14.4% of all pregnancies, 1.5% screened positive for RBC abs. Almost three-quarters (679/100 000 [74.3%]) of RBC abs identified were high risk for HDFN. Although prevalence of anti-D is difficult to interpret without the ability to distinguish alloimmunization from passive immunity, it remains problematic in HDFN, ranking second only to anti-K in critical titers. Given the sequelae of HDFN, new initiatives are required to reduce the incidence of alloimmunization in patients of reproductive potential.

Heidenhain variant of Creutzfeldt-Jakob disease masquerading as neuromyelitis optica spectrum disorder: recognizing when apheresis is not the answer.

The Heidenhain variant of Creutzfeld-Jakob disease (CJD) is a rare form that initially presents with visual disturbances. In early stages, the presentation can mimic neuromyelitis optica spectrum disorders (NMOSD) and lead to unnecessary treatment modalities. Herein, we describe a case of a 66-year-old man who presented with bilateral vision loss and retro-orbital discomfort. In addition to immunosuppressive therapy, he received 4 rounds of therapeutic plasma exchange after his preliminary diagnosis of NMOSD. We were surprised to note that his condition did not show improvement but deteriorated, with severe neurocognitive symptoms. Eventually, CJD was suspected, and real-time quaking-induced conversion (RT-QuIC) was performed. By the time the diagnosis of Heidenhain variant of CJD was confirmed, the patient was discharged to hospice care and died shortly after.

Warm autoantibodies mimicking alloantibodies: Three cases of autoantibodies with unusual antigenic specificity.

OBJECTIVES: We describe 3 cases of red blood cell (RBC) autoantibodies with unusual apparent antigenic specificity and discuss the testing methodology and implications of these findings. METHODS: All immunohematologic testing, including ABO and RhD typing, antibody detection and identification, RBC antigen phenotyping and genotyping, direct antiglobulin tests, and elution studies were performed using standardized and validated methods and reagents. RESULTS: Three patients were found to have autoantibodies, which were originally presumed to be alloantibodies. Case 1 was a 60-year-old man with autoanti-Jka following babesiosis; case 2 was a 79-year-old woman with an autoanti-f; and case 3 was a 28-year-old pregnant woman with an autoanti-S. Cases 1 and 2 required RBC transfusions, which were performed with Jka-negative and f-positive RBC units, respectively. No transfusion reactions were reported, and the hemoglobin responded appropriately in both cases. CONCLUSIONS: These 3 cases complement the minimal literature regarding warm autoantibodies with unusual antigenic specificity and their potential to mediate clinically significant hemolysis. There are only rare reports of warm autoantibodies with specificity for non-Rh antigens, and prior authors have suggested that autoantibodies with mimicking specificity are usually detected only serologically; in contrast, 2 of the 3 patients herein experienced autoimmune hemolytic anemia.