In a separate evaluation, it was found that endothelial cells can produce NF-κB-inducing kinase, a key player in non-classical NF-κB signaling triggered by LTβ receptor signaling, which contributes to the formation of TLSs in RA.437 This highlights the complexity of cellular interactions and signaling pathways involved in the progression and severity of RA, underscoring the importance of TLSs and mast cells in the disease’s pathology. The gene discussed is NFKB1; the disease is rheumatoid arthritis.