Drug repurposing for cytokine storm: baricitinib, ciclesonide, and acalabrutinib modulate cytokine release in a translational in vitro lymphoblastoid cell line model

Cytokine storm, a life-threatening hyperinflammatory response seen in severe infections like COVID-19, autoimmune diseases, and certain therapies, remains difficult to treat due to limited approved therapeutics. To support preclinical drug development and repurposing in line with 3R principles, we present a novel in vitro model for screening of cytokine-modulating compounds. Herein, we demonstrate that lymphoblastoid cell lines (LCL cells), derived from healthy donors, provide a translationally relevant and phenotypically diverse platform for cytokine profiling and drug screening. Upon stimulation with PMA/ionomycin, LCL cells exhibited a robust secretion of pro-inflammatory (IL-6, IL-8, TNF-α) and anti-inflammatory (IL-10) cytokines, closely mirroring the cytokine profile of activated whole blood. Compared to established immune cell lines THP-1 and Jurkat, LCL cells showed broader cytokine responses and retained interindividual variability. We validated the model for cytokine-modulating drug screening using two well-established immunosuppressants, dexamethasone and cyclosporin A. Dexamethasone reduced IL-6 by 21 %, IL-8 by 71 %, IL-12 by 68 %, TNF-α by 83 %, and increased IL-10 by 51 %. Cyclosporin A lowered IL-6 by 34 %, IL-8 by 69 %, IL-10 by 48 %, and TNF-α by 41 %. Subsequently, we tested a panel of clinically investigated COVID-19 therapies, selected based on a comprehensive literature review. Ciclesonide and acalabrutinib showed strong suppression of all measured cytokines by more than 60 %, while baricitinib, which has become a standard of care for severe COVID-19, reduced IL-6 by 70 %, IL-12 by 68 %, and TNF-α by 47 %, but had minimal effect on IL-8. Notably, LCL cells retained interindividual variability, as demonstrated by diverse cytokine as well as divergent NF-κB nuclear translocation responses, supporting the model's capacity to reveal real-world patient heterogeneity. Collectively, our findings establish LCL cells as a reproducible, immunologically responsive, and patient-representative platform for cytokine storm research and high-content drug testing, providing both mechanistic insight and translational relevance.