CXCL8 and obesity due to melanocortin 4 receptor deficiency: The immune cell infiltration of adipose tissue increased production of pro-inflammatory cytokines (e.g., TNF-α, IL-1, IL-6, and IL-8) that were reported to be associated with increased risk of nephritis in HSP [17,18], which may be a potential mechanism to explain the relationship between obesity and HSPN.