We found that patients who have hyposialylated pc IgGs in addition to mc IgGs secrete several pro-inflammatory cytokines (IL-6, TNF-α, TGF-β, IL-17, and IL-33) or cytokines involved in MM progression (HGF) at significantly higher levels than patients with hyper-sialylated pc IgGs. Here, IL6 is linked to Miyoshi myopathy.