One day after secondary skin infection, the paracortical zone showed a decrease in the surface area positively stained for the presence of T helper cells (CD4+), dendritic cells (OX62+), stem cells, immature B cells and thymocytes (CD90+), and endothelial cells (CD31+) compared with the early evaluation (day 8) after the initial infection. The gene discussed is PECAM1; the disease is skin infection.