Interestingly, while no changes in HFD were seen on HDM-induced changes in markers of Th2 response (eosinophilic and CD4+ T cell infiltration, levels of allergen-specific IgE, and the expression of Il5 and Il13 cytokines), obesity markedly increased cytokines such as Tnfa, Il-1b, Tgf-b and Il17 when compared to HDM-exposed and -sensitised lean mice. This evidence concerns the gene IL17A and obesity due to melanocortin 4 receptor deficiency.