Objectives: The most recently introduced therapeutics for psoriasis are biologicals which can target the T-cell-mediated pathology of psoriasis in a direct or indirect manner. The present pilot study focuses on and compares the effect of a conventional systemic agent (methotrexate; MTX) with the effect of a TNF-binding biological (adalimumab) on psoriasis-associated T-cell subsets in peripheral blood (PB) and lesional skin. Insight is provided in the hypothesized compartmentalization of these T-cell subsets between PB and the cutaneous compartment.
Methods: Immunohistochemical stainings of designated T-cell subsets on psoriatic skin sections were performed and similar subsets were isolated from PB specimens by flow cytometry. These counts were correlated with clinical severity.
Results: Results showed that adalimumab had a greater clinical effect than MTX treatment after 12 weeks. In the dermis, only the CD3+ T cells were significantly reduced after 12 weeks of adalimumab therapy, whereas for MTX only CD3+ T cells in the epidermis and CD45RO+ T cells in the dermis reduced significantly. However, PB T-lymphocyte populations did not show significant shifts in quantification of T-cell subsets.
Conclusion: Therefore, recompartmentalization of psoriasis-associated T-cell subsets between PB and lesional skin was not induced in this study as a therapeutic principle. Consequently, recompartmentalization of T-cell subsets does not seem an obligatory event in order to achieve good clinical response.