TNF and psoriasis: Among the pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin 1-β (IL-1β) have a wide range of biological activities on numerous cell types and are reported to be involved in the pathogenesis of various inflammatory disorders, such as rheumatoid arthritis, inflammatory bowel disease, osteoarthritis, psoriasis, endotoxemia, and/or toxic shock syndrome, different types of cancer, and degenerative diseases of the central nervous system [3,6,7].