CCR4 T cell recruitment to the skin in mycosis fungoides: potential contributions by thymic stromal lymphopoietin and interleukin-16

Mycosis fungoides (MF) is characterized by skin accumulation of CCR4 � CCR7- eff ector memory T cells; however the mechanism for their recruitment is not clearly identifi ed. Thymic Stromal Lymphopoietin (TSLP) is a keratinocyte-derived cytokine that triggers Th2 immunity and is associated with T cell recruitment to the skin in atopic dermatitis. Interleukin-16 (IL-16) is a chemoattractant and growth factor for CD4 � T cells. We hypothesized that TSLP and IL-16 could contribute to recruitment of malignant T cells in MF. We found elevated TSLP and IL-16 in very early stage patients ’ plasma and skin biopsies, prior to elevation in CCL22. Both TSLP and IL-16 induced