In severe ROP vs no ROP, IGF-1, MIP (macrophage inflammatory protein)-1β, IL-1β and IL-8 were different in cord blood, BDNF (brain-derived neurotrophic factor) and IGF-1 differed in peripheral blood on day one and IGF-1 differed in the period of first month after birth (Table 3). This evidence concerns the gene CXCL8 and retinopathy of prematurity.