Early life determinants of skin-resident T cells

Recent research has shown that sequential colonization of the skin by various subsets of immune cells, particularly T cells, during perinatal stages forms layered surveillance networks crucial for maintaining skin tissue integrity and function. Here, we review our current understanding of key epigenetic and molecular mechanisms, along with maternal/external environmental factors, that regulate the sequential colonization of skin by different T cell subsets and their roles in establishing and maintaining skin tissue homeostasis. We propose that establishment of a skin-resident T cell system is developmentally programmed in coordination with maturation of skin structural barriers to adapt to environmental changes during perinatal stages, while dysregulation during this critical 'window of opportunity' could have lifelong impacts on the health of both the skin and body.