AbstractNeurotrophins (NTs), including nerve growth factor (NGF), are multifunctional: in addition to their well‐characterized neurotrophic functions they are known to regulate and to be regulated by cytokines, components of the immune system. In line with this we have found expression of a functional trk proto‐oncogene, constituting the signal transducing‐receptor for NGF, on monocytes/macrophages, lymphocytes and basophils. Moreover, NGF synthesis is regulated by a cytokine cascade including inflammatory mediators such as interleukin‐1 and tumor necrosis factor‐α. The fact that NGF levels are markedly elevated in cerebrospinal fluid of patiens with multiple sclerosis and in serum of patients with systemic lupus erythematosus strongly indicates a role for NGF in immunopathology as well as in normal immune function.