To explore the immune response to CS, we prospectively measured, in 24 consecutive CS patients, differential white blood cell (WBC) counts and the cytokines IL-1β, IL-5, IL-6, IL-10, TNFα, IFNγ, MCP-1 and eotaxin (CCL11), at Day 1 (T1), day 3 (T2) and day 6-8 (T3). The gene discussed is IL5; the disease is Cowden syndrome 1.