Patients with certain chronic autoimmune disorders such as rheumatoid arthritis and psoriasis can have increased levels of GM-CSF in serum and affected tissues, suggesting a possible role for this cytokine in the pathogenesis of these conditions and providing the rationale for therapeutic targeting of GM-CSF using exogenous GM-CSF monoclonal antibodies (115, 116). Here, CSF2 is linked to psoriasis.