There is good evidence from the murine passive cutaneous anaphylaxis model and delayed hypersensitivity reactions in skin, that leukocyte recruitment is dependent on MC-derived TNFα (51, 133), and that CD8+ dendritic cell migration to draining lymph nodes of the skin also relies on MC TNFα (68, 134) (Figure 1). This evidence concerns the gene TNF and type IV hypersensitivity disease.