RT Journal Article SR Electronic T1 Effects of targeting the transcription factors Ikaros and Aiolos on B cell activation and differentiation in systemic lupus erythematosus JF Lupus Science & Medicine JO Lupus Sci Med FD Lupus Foundation of America SP e000445 DO 10.1136/lupus-2020-000445 VO 8 IS 1 A1 Felice Rivellese A1 Sotiria Manou-Stathopoulou A1 Daniele Mauro A1 Katriona Goldmann A1 Debasish Pyne A1 Ravindra Rajakariar A1 Patrick Gordon A1 Peter Schafer A1 Michele Bombardieri A1 Costantino Pitzalis A1 Myles J Lewis YR 2021 UL http://lupus.bmj.com/content/8/1/e000445.abstract AB Objective To evaluate the effects of targeting Ikaros and Aiolos by cereblon modulator iberdomide on the activation and differentiation of B-cells from patients with systemic lupus erythematosus (SLE).Methods CD19+ B-cells isolated from the peripheral blood of patients with SLE (n=41) were cultured with TLR7 ligand resiquimod ±IFNα together with iberdomide or control from day 0 (n=16). Additionally, in vitro B-cell differentiation was induced by stimulation with IL-2/IL-10/IL-15/CD40L/resiquimod with iberdomide or control, given at day 0 or at day 4. At day 5, immunoglobulins were measured by ELISA and cells analysed by flow cytometry. RNA-Seq was performed on fluorescence-activated cell-sorted CD27-IgD+ naïve-B-cells and CD20lowCD27+CD38+ plasmablasts to investigate the transcriptional consequences of iberdomide.Results Iberdomide significantly inhibited the TLR7 and IFNα-mediated production of immunoglobulins from SLE B-cells and the production of antinuclear antibodies as well as significantly reducing the number of CD27+CD38+ plasmablasts (0.3±0.18, vehicle 1.01±0.56, p=0.011) and CD138+ plasma cells (0.12±0.06, vehicle 0.28±0.02, p=0.03). Additionally, treatment with iberdomide from day 0 significantly inhibited the differentiation of SLE B-cells into plasmablasts (6.4±13.5 vs vehicle 34.9±20.1, p=0.013) and antibody production. When given at later stages of differentiation, iberdomide did not affect the numbers of plasmablasts or the production of antibodies; however, it induced a significant modulation of gene expression involving IKZF1 and IKZF3 transcriptional programmes in both naïve B-cells and plasmablasts (400 and 461 differentially modulated genes, respectively, false discovery rate<0.05).Conclusion These results demonstrate the relevance of Ikaros and Aiolos as therapeutic targets in SLE due to their ability to modulate B cell activation and differentiation downstream of TLR7.