The experiments performed on C57Bl/6J (wild-type controls), nude (B6.Cg—Foxn1 nu), immunodeficient SCID (B6.CB17—Prkdc SCID/SzJ), Rag (B6.129S7—Rag1tm1Mom) (lack of B and T cells), athymic (thymectomized neonates and adults C57Bl/6J) and cyclosporine A-treated mice were designed to test the hypothesis that T-cell deficiency and/or lack of a thymus promote scar-less skin repair in mice. The gene discussed is FOXN1; the disease is congenital T-cell immunodeficiency.