Circulating CLA+ T lymphocytes as peripheral cell biomarkers in T‐cell‐mediated skin diseases

Abstract

T lymphocytes expressing the CLA antigen constitute a subset of effector memory lymphocytes that are functionally involved in T-cell-mediated cutaneous diseases. Skin-seeking lymphocytes recirculate between inflamed skin and blood during cutaneous inflammation. Many studies in different T-cellmediated inflammatory cutaneous diseases have clearly related their pathologic mechanisms to CLA+ T cells. Based on common features of these cells in different cutaneous disorders mediated by T cells, we propose that circulating CLA+T cells could constitute very useful peripheral cellular biomarkers for T-cell-mediated skin diseases.

Human Translational Research in Psoriasis Using CLA+ T Cells

“…The molecular interactions between CLA/E-selectin, very late antigen-4 (VLA-4)/vascular cell adhesion protein-1 (VCAM-1), lymphocyte function-associated antigen-1 (LFA-1)/intercellular adhesion molecule-1 (ICAM-1), and chemokine ligands for chemokine, C-C motif receptor (CCR) 10, CCR4, CCR6, and CCR8 constitute a code bar system enabling skin iniltration [3].…”

“…This feature is based on the recirculating capacity of those cells between lesional skin and blood during cutaneous inlammation in psoriasis [3]. The adhesive interaction between LFA-1 and ICAM-1 is one of the mechanisms involved in the transendothelial migration of CLA+ T cells [4].…”

“…Interestingly, the blockade of LFA-1/ICAM-1 interaction in psoriasis patients with anti-LFA-1 in patients blocks extravasation and leads to CLA+ T cell lymphocytosis. Such accumulation of CLA+ T cells in the blood has clinical relevance since skin relapse may develop after stopping the anti-LFA-1 treatment [3].…”

“…In addition, their phenotype and function are related to clinical status of the patient. For these reasons, those cells are considered peripheral cell biomarkers of T-cell mediated human cutaneous diseases [3,5,6]. …”

“…Interestingly, the blockade of LFA-1/ICAM-1 interaction in psoriasis patients with anti-LFA-1 in patients blocks extravasation and leads to CLA+ T cell lymphocytosis. Such accumulation of CLA+ T cells in the blood has clinical relevance since skin relapse may develop after stopping the anti-LFA-1 treatment [3].The function and phenotype of circulating CLA+ T cells in T-cell mediated skin disease have been studied in many diferent human skin conditions. Those skin-seeking memory T cells respond to antigens, allergens, or superantigens that play a key role in disease triggering of diferent human T-cell mediated skin diseases, see Table 1.…”