As anti-IL-5 therapy is now in the clinic, it will be interesting to assess the expression and function of ITIM-bearing receptors in eosinophils from human patients before and after treatment and to assess whether any metabolic (e.g. obesity, diabetes) alterations occur in individuals chronically treated with anti-IL-5 therapy. This evidence concerns the gene IL5 and obesity due to melanocortin 4 receptor deficiency.