Further protein network analysis showed that PPARD directly interacts with several allergy and inflammation proteins such as fatty acid-binding protein (FABP5) (80, 81), retinoic acid receptor RXR-alpha (RXRA) (82), pyruvate dehydrogenase E1 component (PDHX) (83), catenin beta-1 (CTNNB1) (84–86), mothers against decapentaplegic homolog 4 (SMAD4) (87, 88) and retinoic acid receptor RXR-beta (RXRB) (89) (Figure 8G) confirming its association with allergy. This evidence concerns the gene SMAD4 and Allergy.