B cells require Type 1 interferon to produce alloantibodies to transfused KEL‐expressing red blood cells in mice

Abstract

Background Alloantibodies to RBC antigens can cause significant hemolytic events. Prior studies have demonstrated that inflammatory stimuli in animal models and inflammatory states in humans, including autoimmunity and viremia, promote alloimmunization. However, molecular mechanisms underlying these findings are poorly understood. Given that type 1 interferons (IFNα/β) regulate antiviral immunity and autoimmune pathology, the hypothesis that IFNα/β regulates RBC alloimmunization was tested in a murine model. Study Design and Methods Leuko-reduced murine RBCs expressing the human KEL glycoprotein were transfused into control mice (WT), mice lacking the unique IFNα/β receptor (IFNAR1−/−), or bone marrow chimeric mice lacking IFNAR1 on specific cell populations. Anti-KEL IgG production, expressed as mean fluorescence intensity (MFI), and B cell differentiation were examined. Results Transfused WT mice produced anti-KEL IgG alloantibodies (peak response MFI=50.4). However, the alloimmune response of IFNAR1−/− mice was almost completely abrogated (MFI=4.2, p<0.05). The response of bone marrow chimeric mice lacking IFNAR1 expression in all hematopoietic cells or specifically in B cells was also diminished (MFI=3.8 and 5.4, respectively, compared to control chimeras, MFI=65.6, p<0.01). Accordingly, transfusion-induced differentiation of IFNAR1−/− B cells into germinal center B cells and plasma cells was significantly reduced, compared to WT B cells. Conclusions This study demonstrates that B cells require signaling from IFNα/β to produce alloantibodies to the human KEL glycoprotein in mice. These findings provide a potential mechanistic basis for inflammation-induced alloimmunization. If these findings extend to human studies, patients with IFNα/β-associated conditions may have an elevated risk of alloimmunization and benefit from personalized transfusion protocols.

Red blood cell alloimmunization is associated with lower expression of FcγR1 on monocyte subsets in patients with sickle cell disease

“…CD64 expression is typically observed in response to IFNγ stimulation of monocytes, and recent in vitro data has shown that IFNα/β suppresses IFNγ responses in macrophages, leading to CD64 downregulation . Although we did not find differences in measured IFNγ levels between responders and non‐responders, our findings in sickle cell patients may be consistent with recent work from our laboratory showing that IFNα/β impacts the ability of a murine transfusion recipient to form RBC alloantibodies to the KEL human blood group antigen expressed on murine RBCs . Taken together, these data suggest that alloimmunized patients with SCD may have higher IFNα/β levels that prevent IFNγ from leading to the same increase in CD64 expression as would be seen in the absence of IFNα/β.…”

“…Recently, studies in an animal model related IFNα/β and RBC alloimmunization, with exogenous IFNα/β increasing the likelihood of a transfusion recipient becoming alloimmunized. Further, recipients lacking type 1 IFN receptors failed to become alloimmunized . Other cytokine genes also have been shown to be more prevalent in alloimmunized patients with SCD compared to non‐alloimmunized patients …”

Type 1 IFN signaling critically regulates influenza‐induced alloimmunization to transfused KEL RBCs in a murine model

“…Influenza infection induces Type 1 interferons (IFN‐α/β) and NFkB‐inducible cytokines, including tumor necrosis factor‐α) and IL‐6, and influenza has also been shown to activate inflammasomes . Given our recent reports suggesting the importance of IFN‐α/β on RBC alloimmunization, we hypothesized that the mechanism through which influenza regulates RBC alloimmunization in this murine model is at least in part dependent on recipient IFN‐α/β signaling. To investigate this hypothesis, we infected wild‐type C57BL/6 mice or mice lacking IFN‐α1 receptors (IFNAR KO) with influenza and transfused them 3 days later with K1 RBCs.…”

Risk factors for red blood cell alloimmunization in the Recipient Epidemiology and Donor Evaluation Study (REDS‐III) database

“…Multiple studies have also described a close association between RBC alloantibodies and RBC autoantibodies (Dhawan et al , ; Nickel et al , ). Animal studies (Gibb et al , ,b) suggest that a potential unifying hypothesis for the connection between some types of autoimmunity (Crow, ) and alloimmunization may involve type 1 interferon signalling.…”