Production of interleukin-8 by circulating CLA+ T cells with skin tropism in patients with psoriasis and in healthy controls

Background: Psoriasis is an immune-mediated disease typically associated with cutaneous neutrophilic infiltration and Munro microabscesses. Interleukin (IL)-8 is one of the main neutrophil-attracting chemokines. Although keratinocytes have traditionally been considered to be the principal source of IL-8 in psoriasis, we present data that suggest that cutaneous lymphocyte associated antigen (CLA)+ T lymphocytes synthesize this cytokine. Material and methods: Six patients with psoriasis and 6 healthy controls were studied. Immunomagnetic separation was used to isolate CLA+ and CLA- T lymphocytes and IL-8 and interferon (IFN)-γ production was quantified for each cell subpopulation using enzyme-linked immunosorbent assay. Finally, gene expression of IL-8 was analyzed by reverse transcriptase-polymerase chain reaction. Results: CLA+ and CLA- T lymphocytes from patients with psoriasis and from controls showed a significantly increased production of IFN-γ when activated, whereas only activated CLA+ T lymphocytes (from patients and controls) synthesized IL-8. The higher level of expression of IL-8 and IFN-γ by CLA+ T lymphocytes in comparison to CLA- cells was confirmed. Discussion: Previous studies have confirmed IL-8 production by T lymphocytes in inflammatory skin diseases with neutrophil-rich infiltrates, such as acute generalized exanthematous pustulosis, Behçet disease, and pustular psoriasis. We have confirmed the role of the subset of T lymphocytes with skin tropism (CLA+) in IL-8 production in nonpustular psoriasis. © 2009 Elsevier España, S.L. y AEDV.