Studies have shown that immune cells, especially T cells, B cells, and myeloid-derived cells, play a significant role in influencing bone metabolism in a study that looked at the role of T regulatory cells (Tregs) in osteogenesis imperfecta (OI), OI mice had a reduced number of Tregs, which led to increased activation of T cells and higher levels of pro-inflammatory cytokines, such as IFN-g and TNF-a. The gene discussed is TNF; the disease is osteogenesis imperfecta.