For example, SAA released from rheumatoid arthritis synoviocytes have been shown to interact with SR-B1 and FPR2 expressed on endothelial cells to induce the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) degradation, and upregulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression. Here, SAA2 is linked to rheumatoid arthritis.