Lymphotoxin alpha1/bate2 (LT α1/β1) are members of the tumor necrosis factor (TNF) superfamily, and plays a pivotal role in the establishment and regulation of the immune system. The predominant form on the lymphocyte surface is the lymphotoxin alpha 1/beta 2 complex (e.g. 1 molecule alpha/2 molecules beta) and this complex is the primary ligand for the lymphotoxin beta receptor (LTβR). The minor complex is lymphotoxin alpha 2/beta 1. Lymphotoxin alpha mediates a large variety of inflammatory, immunostimulatory, and antiviral responses, is involved in the formation of secondary lymphoid organs during development and plays a role in apoptosis. Genetic variations in this gene are associated with susceptibility to leprosy type 4, myocardial infarction, non-Hodgkin's lymphoma, and psoriatic arthritis. Lymphotoxin beta is an inducer of the inflammatory response system and involved in normal development of lymphoid tissue.