Kirchner F, et al. - Authors evaluated the dynamics of innate immunity markers collected from the surface of infant skin during the first 36 months of life. Using transdermal analysis patches from the skin surface of the posterior lower leg area human beta defensin-1 and interleukin 1 alpha and its receptor antagonist were extracted. Results demonstrated that like skin structure and functional properties, cutaneous innate immunity also appeared to undergo a maturation period during infancy, with innate immunity slowly declining as adaptive immunity took over. Sex-dependent susceptibilities to infection could be explained by the sex differences in immune markers.