The potential immunomodulatory effects of topical retinoids

When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...

Acne is a multifactorial skin condition primarily affecting adolescents and young adults, with a global prevalence estimated to exceed 75% in this demographic. The condition is characterized by the formation of comedones (blackheads and whiteheads), papules, pustules, nodules, and, in severe cases, cysts, particularly in areas rich in sebaceous glands such as the face, neck, chest, and back. The pathogenesis involves increased sebum production, follicular hyperkeratinization, colonization by...

The papillary and reticular dermis are the two layers of the dermis. They are made of connective tissue with fibers of collagen extending from one to the other, making the border between the two somewhat indistinct. The dermal papillae extending into the epidermis belong to the papillary layer, whereas the dense collagen fiber bundles below belong to the reticular layer.
Reticular Layer
Underlying the papillary layer is the much thicker reticular layer, composed of dense, irregular connective...