To explore the site of ICAM-1 and PDGF-B expression and its relationship with NOD2 expression in Blau syndrome lesions, ICAM-1 and PDGF-B protein expression in the lesional skin specimen of a Blau syndrome patient harboring the NOD2 R334W mutation was examined immunohistochemically and by double-immunofluorescence staining with NOD2. The gene discussed is NOD2; the disease is Blau syndrome.