The effect of topical corticosteroids in combination with alefacept on circulating T-cell subsets in psoriasis

Novel therapies against psoriasis are emerging. Alefacept is such a treatment. It selectively targets the memory effector population of T cells and thereby diminishes the psoriatic plaques. In some cases, however, the use of alefacept as a monotherapy is not sufficient.

In the present study we investigate the safety and efficacy of adding topical steroids to alefacept treatment during the initial 4 weeks.

Peripheral blood was obtained from all patients and the presence of specific T-cell subsets was assessed by flow cytometry. Fourteen patients were included and treated with 15 mg alefacept intramuscularly for a period of 12 weeks. Each of them was randomized to use either betamethasone-dipropionate cream or a vehicle cream during the first 4 weeks of the alefacept course.

Additional topical corticosteroid treatment during the first 4 weeks of alefacept treatment does not have a beneficial effect on the clinical efficacy. Marked changes were seen in the absolute cell counts of various of the analysed T-cell subsets in peripheral blood after 12 weeks of alefacept, either with or without additional local steroid application. The CD45RO+, CD8+CD45RO+, CD8+CD161+, CD4+CD25+, CD4+CLA+ and CD8+CLA+ populations showed a statistically significant decrease immediately after the treatment period. Further analysis revealed that the addition of local steroid therapy to alefacept results in marked decreases of all T-cell subsets analysed in this study, in contrast to the addition of the vehiculum only.

Alefacept selectively targets the CD45RO+ lymphocyte population, as well as some other subpopulations of lymphocytes. This effect is independent of the use of additional topical therapy during the first 4 weeks. The extent of the decrease, on the contrary, is dependent on the use of corticosteroids.