Red blood cell (RBC) transfusion exposes recipients to hundreds of unmatched minor RBC antigens. This exposure can lead to production of alloantibodies that promote clinically significant hemolytic events. Multiple studies have reported an increased frequency of RBC alloimmunization in patients with autoimmunity. However, cellular and molecular mechanisms that underlie autoimmunity-induced alloimmunization have not been reported. Patients with systemic lupus erythematosus (SLE) have a high frequency of alloimmunization and express a type 1 interferon (IFNα/β) gene signature. Thus, we utilized the pristane-induced lupus mouse model to test the hypothesis that inflammation in lupus promotes RBC alloimmunization, and to examine the potential role of IFNα/β. Intraperitoneal injection of pristane, a hydrocarbon oil, led to autoantibody production, glomerulonephritis, and pulmonary hemorrhage in wild type (WT) mice. Pristane treatment significantly induced serum IFNα and expression of multiple interferon-stimulated genes (ISGs) in peripheral blood and peritoneal fluid cells, including inflammatory macrophages. Following transfusion with allogeneic RBCs expressing the KEL glycoprotein, pristane-treated WT mice produced significantly elevated levels of anti-KEL IgM and anti-KEL IgG, compared to untreated mice. Pristane induced comparable levels of inflammatory cells and cytokines in mice lacking the IFNα/β receptor (IFNAR1 −/−) or the IFNα/β-inducing transcriptions factors (IRF3/7 −/−), compared to WT mice. However, pristane-treated IFNAR1 −/− and IRF3/7 −/− mice failed to produce ISGs and produced significantly lower levels of transfusion-induced anti-KEL IgG, compared to WT mice. Thus, pristane induction of a lupus-like phenotype promoted alloimmunization to the KEL RBC antigen in an IFNα/β-dependent manner. To our knowledge, this is the first examination of molecular mechanisms contributing to RBC alloimmunization in a model of autoimmunity. These results warrant further investigation of the role of IFNα/β in alloimmunization to other RBC antigens and the contribution of the IFNα/β gene signature to the elevated frequency of alloimmunization in patients with SLE.
Background: Red blood cell (RBC) alloimmunization can follow exposure to foreign RBC antigens during transfusion therapy and during pregnancy/delivery. Alloantibodies against RBC antigens can cause potentially fatal hemolytic transfusion reactions and hemolytic disease of the newborn. Recent studies indicate that inflammatory states, including autoimmunity, promote RBC alloimmunization. For example, patients with systemic lupus erythematosus (SLE) have an elevated risk of RBC alloimmunization. Approximately 50% of SLE patients have a pro-inflammatory type 1 interferon (IFNα/β) gene signature, defined as the expression of interferon stimulated genes (ISGs), that is associated with disease severity. Recent studies in mouse transfusion models indicate that IFNα/β significantly promotes RBC alloimmunization. Thus, we hypothesized that IFNα/β produced in a lupus mouse model would promote RBC alloimmunization following transfusion. Methods: To test this hypothesis, we utilized the pristane-induced lupus mouse model, known to manifest lupus autoantibodies and a lupus-like phenotype. Mice lacking the IFNα/β receptor (IFNAR1-/-), mice lacking transcription factors required for IFNα/β production (IRF3/7-/-) and wildtype (WT) mice were administered an intraperitoneal injection of pristane 14 days prior to transfusion with transgenic RBCs expressing the KEL antigen. At the time of transfusion, serum IFNα levels were measured by ELISA, and expression of interferon stimulated gene 15 (ISG15) was measured by quantitative PCR. The mean fluorescence intensity (MFI) of the anti-KEL IgM and IgG responses were measured by flow cytometry 5 days and 7-28 days, respectively, following transfusion. A Mann-Whitney U test and a Kruskall-Wallis test with a Dunn's post-test was used to compare 2 or more than 2 groups, respectively. Results: Pristane induced serum IFNα in WT mice (Day 14 post-pristane, mean IFNα=127.3 Units/ml ± 28.21 standard error of the mean, SEM, p<0.01), which was undetectable in untreated mice. Pristane treatment also resulted in a non-significant trend toward upregulated expression of ISG15, post-pristane ISG15 =2.94 ± 1.16 SEM; no pristane ISG15 = 1.4 ± 0.2 SEM). Following transfusion, untreated mice did not form anti-KEL IgG. However, pristane-treated WT mice produced significantly elevated levels of anti-KEL IgM and anti-KEL IgG in 3 out of 3 experiments (untreated IgM MFI = 79.1 ± 13.5, pristane-treated IgM MFI = 142.7 ± 21.6, p<0.01; untreated IgG MFI = 10.7± 4.6, pristane-treated IgG MFI= 203.9 ± 99.6, p<0.05, Figure 1). Pristane-treated IFNAR1-/- and IRF3/7-/- mice produced significantly lower levels of anti-KEL IgG (IFNAR1-/- MFI = 39.0 ± 35.6, p<0.05; IRF3/7-/- MFI = 36.1 ± 16.3, p<0.02) compared to WT mice (MFI = 361 ± 148). Conclusion: Pristane induction of a lupus-like phenotype promoted alloimmunization to the KEL RBC antigen in an IFNα/β-dependent manner. These results warrant further investigation of the role of IFNα/β in alloimmunization to other RBC antigens, and the investigation of the contribution of IFNα/β responses to increased frequency of alloimmunization in patients with SLE. Disclosures No relevant conflicts of interest to declare.
Red blood cell (RBC) transfusion exposes recipients to hundreds of unmatched minor RBC antigens. This exposure can lead to production of alloantibodies that can cause potentially fatal hemolytic events. Prior studies have reported that inflammatory states, including autoimmune disease, in the transfusion recipient can promote alloimmunization. Recent studies reported that pro-inflammatory type 1 interferons (IFNα/β) regulated RBC alloimmunization in multiple mouse transfusion models. Interestingly, patients with systemic lupus erythematosus (SLE) have an increased frequency of alloimmunization and express an IFNα/β gene signature. Thus, we tested the hypothesis that IFNα/β activation in lupus promotes RBC alloimmunization by utilizing the pristane-induced lupus mouse model. Pristane significantly induced serum IFNα and expression of multiple interferon-stimulated genes (ISG) in peritoneal fluid cells, including inflammatory macrophages. Following transfusion with allogeneic RBCs expressing the KEL antigen, pristane-treated WT mice produced significantly elevated levels of anti-KEL IgM and anti-KEL IgG, compared to untreated mice. Pristane-treated mice lacking the IFNα/β receptor (IFNAR1−/−) or IFNα/β-inducing transcription factors (IRF3/7−/−) mice failed to produce ISGs and produced significantly lower levels of anti-KEL IgG compared to WT mice. In conclusion, pristane induction of a lupus-like phenotype promoted alloimmunization to the KEL RBC antigen in an IFNα/β-dependent manner. These results warrant further investigation of the role of IFNα/β in alloimmunization to other RBC antigens and the contribution of IFNα/β responses to the increased frequency of alloimmunization in patients with SLE.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.