Low degree of DNA polymorphism in the HLA-linked lymphotoxin (tumour necrosis factor beta) gene.

Tumour necrosis factors (TNF) alpha (cachectin) and beta (lymphotoxin) are lymphokines with many biological activities. For example, the molecules regulate the immune system, which is of special interest since the genes for the TNF are located within the human major histocompatibility complex (MHC). The MHC encodes HLA-molecules that play a critical role in the cellular interactions of the immune response. To test whether genetic polymorphism in the TNF genes may be involved in the associations between HLA and autoimmune diseases, we here describe an analysis of DNA polymorphism in the human TNF-beta gene. The results show that the TNF-beta gene has only a low degree of DNA polymorphism, and that this is not associated with HLA antigens showing a strong association with autoimmune-like diseases.