IL-4 (Interleukin 4) is a potent lymphoid cell growth factor th at stimulates the growth and survivability of certain B cells and T cells. It exhibits anti-inflammatory responses and participates in immune processes by providing protection from intracellular pathogens. IL-4 also plays an important role in Th2 (T helper cells) differentiation. Additionally, it can suppress pro-inflammatory cytokines. IL-4 is associated with pemphigus. Also, mutation in the gene is linked with risk of dental implant loss. In children, IL-4 might be involved with risk of asthma and Mycoplasma pneumoniae infection.