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

Abstract

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.

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

Figure 1

Type 1 T cells (IFN-γ producing) are decreased with alefacept therapy. Intracellular cytokine FACS detection of mean number of TNF-α, IL-2 and IFN-γ cells/ml, which are significantly decreased with therapy, P value indicated.

Figure 2

T cells can still be activated during treatment with Alefacept. Percent CD69 positive cells following in vitro activation with control, anti-CD3 (OKT3) or anti-CD2 (T11.1 and T11.2). Comparison of CD69 expression on T cells activated with either OKT3 or T11.1 and T11.2 at baseline and week 13. No significant differences. Geometric mean data, standard error of the mean.