Measurement of serum GM3 species will potentially allow evaluation of hidden risks of TLR4‐signaling‐related inflammatory diseases (e.g., inflammatory bowel disease, chronic kidney disease, rheumatoid arthritis, cancer metastasis) via LPS and endogenous ligands such as HMGB1, S100A8/9 (Mrp8/14), and SAA3 (Vogl et al, 2007; Hiratsuka et al, 2008; Harris et al, 2012). Here, SAA3P is linked to rheumatoid arthritis.