Interleukin-34 (IL-34) is a new proinflammatory factor found in the interleukin family in recent years. It is found in human spleen, thymus, liver, large intestine, small intestine, lung, heart, prostate, brain, kidney, Found in testis, ovary and skin, secreted by keratinocytes, spleen sinus epithelial cells, synovial fibroblasts and neurons, can stimulate the differentiation, proliferation and survival of monocytes and macrophages, and also promote colony giants. The phagocytes release pro-inflammatory cytokines. There are data showing that IL-34 is present in diseases such as rheumatoid arthritis, Sjogren's syndrome, and cancer.