GRN and type 2 diabetes mellitus: Few other members of the adipokine family, namely adiponectin, progranulin (PGRN), and lipocalin-2 (LCN2) are also found to exhibit vital links between immune system and obesity, thus making adipokines attractive biomarkers for obesity-related diseases, such as Type 2 diabetes mellitus, osteoarthritis, and rheumatoid arthritis [18,19,20].