TNF and asthma: VEGF is upregulated by inflammatory cytokines such as IL-6 [9], tumor necrosis factor-α (TNF-α) [10], and IL-8 [11], and may play a major role in inflammatory diseases such as rheumatoid arthritis [12], asthma [13], Churg-Strauss syndrome [14] and Behcet's disease [15].