Alefacept (anti-CD2) causes a selective reduction in circulating effector memory T cells (Tem) and relative preservation of central memory T cells (Tcm) in psoriasis.

Background: Alefacept (anti-CD2) biological therapy selectively targets effector memory T cells (Tem) in psoriasis vulgaris, a model Type 1 autoimmune disease.

Methods: Circulating leukocytes were phenotyped in patients receiving alefacept for moderate to severe psoriasis.

Results: In all patients, this treatment caused a preferential decrease in effector memory T cells (CCR7- CD45RA-) (mean 63% reduction) for both CD4+ and CD8+ Tem, while central memory T cells (Tcm) (CCR7+CD45RA-) were less affected, and naïve T cells (CCR7+CD45RA+) were relatively spared. Circulating CD8+ effector T cells and Type 1 T cells (IFN-gamma-producing) were also significantly reduced.

Conclusions: Alefacept causes a selective reduction in circulating effector memory T cells (Tem) and relative preservation of central memory T cells (Tcm) in psoriasis.