TNF and psoriasis: Some studies have shown that cigarette smoking induces an overproduction of interleukin 1β (IL-1β) and increases the production of tumor necrosis factor α (TNF-α) and transforming growth factor β (TGF-β), which have been associated with the severity of the psoriasis [3] and also explains some of the associated comorbidities: cardiovascular disease, inflammatory bowel disease and several cancers [4].