The different stages of disease progression from MGUS to smoldering/symptomatic-MM are related to a progressive increase in cytokine levels (e.g., IL-1, IL-6, IL-12, IL-15, IL-17, IL-18, IL-22, IL-23, TNF-a and IFN-g) in the serum of MM patients. Here, IL15 is linked to Miyoshi myopathy.