Tumour necrosis factor alpha and mucocutaneous leishmaniasis

Allelic associations between polymorphisms at the tumour necrosis factor (TNF) locus within the major histocompatibility complex (MHC) and susceptibility to a range of autoimmune and infectious diseases have been established in humans. Among these is the severe and debilitating mucocutaneous form of leishmaniasis (MCL) caused by Leishmania braziliensis. This was pre-empted by the demonstration of high levels of circulating TNF-alpha in the sera of patients presenting with clinical mucocutaneous disease. Here, Jennie Blackwell looks at the implications this might have for the diagnosis and treatment of mucocutaneous disease, and the broader implications that the positive and negative immunomodulatory roles of TNF-alpha have in maintaining apparently detrimental alleles in the population.