Role of non-classical T cells in skin immunity

Immune watchdogs: Tissue-resident lymphocytes as key players in cancer defense

Tissue-resident lymphocytes play a crucial role in immune surveillance against cancer, yet their complex interactions and regulatory pathways remain underexplored, highlighting the need for a deeper understanding to enhance cancer immunotherapy strategies. Lymphocytes across the range of innate-adaptive responses can establish long-lasting presence in tissues, exerting a vital function in the local immune response against diverse antigens. These tissue-resident lymphocytes identify antigens and alarmins secreted by microbial infections and non-infectious stresses at barrier locations by closely interacting with epithelial and endothelial cells. Then they initiate effector responses to restore tissue homeostasis. Significantly, this immune defense system has been demonstrated to monitor the processes of epithelial cell transformation, carcinoma advancement, and cancer metastasis at remote locations, so establishing it as an essential element of cancer immunological surveillance. This review aims to elucidate the roles of diverse tissue-resident lymphocyte populations in shaping cancer immune responses and to investigate their synergistic effector mechanisms for advancing cancer immunotherapy.

T-cell subsets in the skin and their role in inflammatory skin disorders

T lymphocytes (T cells) are major players of the adaptive immune response. Naive T cells are primed in the presence of cytokines, leading to polarization into distinct T-cell subsets with specific functions. These subsets are classified based on their T-cell receptor profile, expression of transcription factors, surface cytokine and chemokine receptors, and their cytokine production, which together determine their specific function. This review provides an overview of the various T-cell subsets and their function in several inflammatory skin disorders ranging from allergic inflammation to skin tumors. Moreover, we highlight similarities of T-cell responses across different skin disorders, demonstrating the presence of similar and opposing functions for the different T-cell subsets. Finally, we discuss the effects of currently available and promising therapeutic approaches to harness T cells in inflammatory skin diseases for which efficacy next to unwanted side effects provide new insights into the pathophysiology of skin disorders.

Nanodermatology-based solutions for psoriasis: State-of-the art and future prospects

Nanodermatology is an emerging, multidisciplinary science, arising from the convergence of nanotechnology, pharmacology, physics/biophysics, chemistry/biochemistry, chemical engineering, material science, and clinical medicine. Nanodermatology deals with (a) skin biology, anatomy, and physiology at the nanoscale ("skin nanobiology"), (b) diagnosis performed by means of novel diagnostic devices, assisted by nanobiotechnologies ("nanodiagnosis"), and (c) treatment through innovative therapeutic agents, including phototherapy ("photonanotherapy"/"photonanodermatology") and systemic/topical drug administration ("nanotherapy") at the nanoscale, and drug delivery-such as transdermal or dermal drug delivery (TDDD/DDD)-enhanced and improved by nanostructures and nanodrugs ("nanodrug delivery"). Nanodermatology, as a super-specialized branch of dermatology, is a quite recent specialty: the "Nanodermatology Society" founded by the eminent dermatologist Dr. Adnan Nasir, was established in 2010, with the aim of bringing together different stakeholders, including dermatologists, nanotechnology scientists, policy-makers and regulators, as well as students and medical residents. Psoriasis has a prevalence of 2-3% worldwide and imposes a severe clinical and societal burden. Nanodermatology-based solutions appear promising for the proper treatment and management of psoriasis, assisting and enhancing different steps of the process of health-care delivery: from the diagnosis to the therapeutics, paving the way for a personalized approach, based on the specific dysregulated biomarkers.

The Dynamics of the Skin's Immune System

The skin is a complex organ that has devised numerous strategies, such as physical, chemical, and microbiological barriers, to protect the host from external insults. In addition, the skin contains an intricate network of immune cells resident to the tissue, crucial for host defense as well as tissue homeostasis. In the event of an insult, the skin-resident immune cells are crucial not only for prevention of infection but also for tissue reconstruction. Deregulation of immune responses often leads to impaired healing and poor tissue restoration and function. In this review, we will discuss the defensive components of the skin and focus on the function of skin-resident immune cells in homeostasis and their role in wound healing.