IL21 and autoimmune disease: In addition, it has been proved that PCs effectively equilibrate T cells and attenuate inflammatory factors (such as IL-17, IL-21, IL-22, IL-23, etc.), suggesting that PC have a favorable prospect in the treatment of inflammatory and autoimmune diseases [39]; Park et al., for instance, discovered that PCs obviously alleviated the clinical symptoms of collagen-induced arthritis in mice via inhibition of IL-17 inflammatory mediator [40].