Biology subjects

Hendrickson, J. E.

Publications and source records attributed to Hendrickson, J. E..

6 recordsLinked to original sources

bioRxiv2025

Predicting Risk of Transfusion-Induced Red Blood Cell Alloimmunization Using Statistical and Machine Learning Approaches in the Recipient Epidemiology and Donor Evaluation Study (REDS-III) Database

Red blood cell (RBC) alloimmunization is a common complication from blood transfusion, often resulting in accelerated donor RBC destruction. Patients show substantial variation in their predisposition to RBC alloimmunization. Previous studies have identified several risk factors, but to our knowledge, there have been no studies that predict risk of RBC alloimmunization by modeling multiple potential risk factors simultaneously. Here, our study represents the first attempt to build prediction models for RBC alloimmunization using the large sample size and rich set of potential risk factors available in the Recipient Epidemiology and Donor Evaluation Study (REDS-III) recipient database. To develop the prediction models, we applied a range of approaches, including traditional statistical models (logistic regression), and modern machine learning (including gradient boosting, random forest, and XGBoost), deep learning (the multilayer perceptron method), and large language models (LLM). XGBoost demonstrates the overall best performance among models providing uncertainty quantification (F1= 0.672 and area under the ROC curve [AUC-ROC]=0.752). LLMs show promising results with the best F1 scores (0.677-0.687), though they are limited by their inability to provide uncertainty estimates, they hold the potential for use as an interactive chatbot for patients. Although there is ample room for performance improvement, limiting the analysis to patients predicted with >80% confidence by XGBoost resulted in a substantially improved AUC-ROC of 0.919, which can be of potential clinical significance.

immunology↗

bioRxiv2025

Red Blood Cell Transfusion is a Non-Canonical Immune Stimulus Characterized by the Suboptimal Induction of CD4+ T Cell Help

Red blood cell (RBC) alloimmunization to non-ABO antigens is a major clinical complication for chronically transfused patients. When exposed to transfused RBCs carrying foreign antigens, some patients generate IgG antibodies that target these antigens, creating potential barriers to future transfusions. Interestingly, other patients produce only IgM antibodies against the same non-ABO antigens, which generally have fewer clinical consequences. Despite the stark differences in their impact, the factors regulating IgM versus IgG production in response to transfused RBCs remain poorly understood. This study explores the balance between IgM and IgG production following transfusion, comparing it to the well-characterized antibody response induced by vaccination in mouse models. By directly assessing antibody levels following RBC transfusion versus Alum-adjuvanted vaccination, we demonstrate that transfusion of RBCs expressing a model antigen is a relatively weak inducer of IgG class switching. Additionally, loss-of-function experiments using CD40L blockade and CD4 depletion confirmed that T cell help is essential for class switching after transfusion but has no effect on IgM production. Most notably, providing supra-physiological levels of T cell help enhanced class switching in a dose-dependent manner after transfusion, whereas vaccination-induced class switching remained unaffected. These findings support a model in which the limited IgG class switching following transfusion stems from suboptimal T cell help compared to vaccination. Furthermore, they suggest that transfusion activates T cells through a non-canonical pathway, distinct from the mechanisms driving immune responses to standard Alum vaccination.

immunology↗

bioRxiv2025

Splenic MARCO+ marginal zone macrophages regulate rapid production of MCP-1 and KC but are dispensable for alloantibody generation in response to stored RBCs in a murine model.

BACKGROUNDAlloimmunization to transfused red blood cells (RBCs) remains a significant clinical problem. However, the cells that initiate immune responses to transfused RBCs remain incompletely characterized. Recently published work has identified splenic marginal zone B (MZB) cells as being critically required for the production of anti-RBC alloantibodies in response to RBCs. In infectious models, MZB cell activation has been shown to depend on a unique population of marginal zone macrophages (MZMs). We hypothesized that MZMs would capture stored RBCs and present them to MZBs, and ultimately MZMs would be required for generation of anti-RBC alloantibodies in response to stored RBC transfusion. STUDY DESIGN AND METHODSStored GFP+ murine RBCs were utilized to determine the splenic localization and erythrophagocytosis by splenic macrophage populations. To determine the functional impact of MZMs, we compared LXR-KO mice, which have been reported to lack MZMs, with wild type mice. Both innate and adaptive immune responses to stored HOD allogenic RBC transfusion were measured in LXR-KO and wild type mice. RESULTSRBC storage leads to a significant increase in the phagocytosis of transfused RBCs by splenic MZMs. LXR-KO mice demonstrated a lack of MZMs and had significantly decreased rapid phase production of cytokines MCP-1 and KC, but similar levels of IL-6. Surprisingly, anti-RBC alloantibody levels were unaffected by the absence of splenic MZMs. CONCLUSIONSSplenic MZMs are involved in the innate response to transfused stored HOD RBCs, contributing to both MCP-1 and KC cytokine production. However, MZMs are dispensable for anti-RBC alloantibody production.

immunology↗

bioRxiv2025

Transfusion of allogenic murine HOD red blood cells preferentially induces low-affinity, short-lived IgG antibodies that are germinal center independent

Transfusion-induced anti-red blood cell (RBC) alloantibodies pose a significant risk to patients who require chronic transfusions. Anti-RBC alloantibodies can be remarkably short-lived (i.e. evanescent), leading to clinically relevant alloantibodies that are not detected in later pre-transfusion antibody screens. Subsequent transfusion of alloantigen-positive RBCs stimulates a rapid memory antibody response that may induce a delayed hemolytic transfusion reaction (DHTR), causing morbidity and occasional mortality in chronically transfused patients. It is unclear why transfusions favor evanescent antibody responses over long-lived antibodies typically observed upon infections and vaccinations. We therefore turned to the HOD mouse model of RBC alloimmunization to elucidate regulators of antibody persistence in response to allogenic transfusions. By following antibody responses over time in transfused mice, we found that HOD-specific alloantibodies rapidly decay within three months while vaccination-induced antibodies remain constant. Thus, the HOD model recapitulates RBC antibody evanescence. The rapid antibody evanescence suggests that transfusion is a poor inducer of germinal centers (GCs), specialized immunological structures where B cells differentiate into germinal center B (GC B) cells and undergo iterative rounds of affinity maturation, ultimately differentiating into long-lived plasma cells that can produce antibodies for decades. Consistent with this hypothesis, we failed to observe an increase in GC B cell formation in response to transfusion, and the majority of anti-RBC alloantibodies were low affinity when compared to vaccination. To formally test the functional requirement for GCs in anti-RBC alloantibody production, we employed two orthogonal approaches to disrupt GC formation: i) day 4 CD40L blockade and ii) genetic disruption of the GC-transcription factor BCL6 selectively in B cells. Both approaches fully blocked GC formation, yet anti-RBC alloantibody production was unchanged. Collectively, our data demonstrate that anti-HOD RBC alloantibodies are GC-independent, low affinity and short-lived. The GC-independence of HOD RBC IgG responses has important implications for understanding the cellular and molecular pathways that regulate the humoral immune response to transfused RBCs, potentially explaining anti-RBC alloantibody evanescence patterns in patients.

immunology↗

bioRxiv2023

Class switching is differentially regulated in RBC alloimmunization and vaccination

BackgroundStudies of human patients have shown that most anti-RBC alloantibodies are IgG1 or IgG3 subclasses, though it is unclear why transfused RBCs preferentially drive these subclasses over others. Though mouse models allow for the mechanistic exploration of class-switching, previous studies of RBC alloimmunization in mice have focused more on the total IgG response than the relative distribution, abundance, or mechanism of IgG subclass generation. Given this major gap, we compared the IgG subclass distribution generated in response to transfused RBCs relative to protein in alum vaccination, and determined the role of STAT6 in their generation. Study Design and MethodsWT mice were either immunized with Alum/HEL-OVA or transfused with HOD RBCs and levels of anti-HEL IgG subtypes were measured using end-point dilution ELISAs. To study the role of STAT6 in IgG class-switching, we first generated and validated novel STAT6 KO mice using CRISPR/cas9 gene editing. STAT6 KO mice were then transfused with HOD RBCs or immunized with Alum/HEL-OVA, and IgG subclasses were quantified by ELISA. ResultsWhen compared to antibody responses to Alum/HEL-OVA, transfusion of HOD RBCs induced lower levels of IgG1, IgG2b and IgG2c but similar levels of IgG3. Class switching to most IgG subtypes remained largely unaffected in STAT6 deficient mice in response to HOD RBC transfusion, with the one exception being IgG2b. In contrast, STAT6 deficient mice showed altered levels of all IgG subtypes following Alum vaccination. DiscussionOur results show that anti-RBC class-switching occurs via alternate mechanisms when compared to the well-studied immunogen alum vaccination.

immunology↗

bioRxiv2021

Innate and adaptive immunity to transfused allogenic red blood cells in mice requires MyD88

Red blood cell (RBC) transfusion therapy is essential for the survival of patients with hematological disorders such as sickle cell anemia. A potentially fatal complication of transfusion is development of non-ABO alloantibodies to polymorphic RBC antigens, yet mechanisms of alloantibody formation remain unclear. Human and mouse RBCs acquire a "storage lesion" prior to transfusion, which in mice contributes to immunogenicity. We previously reported that mouse splenic dendritic cells (DCs) are required for RBC alloimmunization and are activated by sterile and leukoreduced mouse RBCs after storage. Yet how syngeneic RBCs activate innate immune pathways to induce DC activation is unknown. We now show that DC activation to transfused RBCs occurs regardless of alloantigen presence, suggesting that RBC damage induced during storage triggers innate immune receptors. We discovered an unexpected dependence of RBC alloimmunization on the Toll-like receptor (TLR) signaling adaptor molecule MyD88. TLRs are a class of pattern recognition receptors (PRRs) that regulate DC activation and signal through two adaptor molecules, MyD88 and TRIF. We show that the inflammatory cytokine response, DC activation, and the subsequent alloantibody response to transfused syngeneic RBCs require MyD88 but not TRIF, suggesting a restricted set of PRRs are responsible for sensing RBCs and triggering alloimmunization.

immunology↗