E-selectin and vascular cell adhesion molecule-1 are critical for initial trafficking of helper-inducer/memory T cells in psoriatic plaques.

BACKGROUND

To better understand local migration of inflammatory cells in psoriasis, we compared immunohistochemically the expression of cell adhesion molecules on endothelial cells of papillary microvessels, a subpapillary microvessel (SPMV), with the phenotypic profile of infiltrating T cells in initial, active, and involuting psoriatic lesions.

RESULTS

Intercellular adhesion molecule-1, E-selectin, and vascular cell adhesion molecule-1 (VCAM-1) on papillary microvessel E-selectin and VCAM-1 on SPMV that had not been detected in normal/noninvolved skin were induced in psoriatic lesions. Intercellular adhesion molecule-1 on SPMV was constitutively expressed in normal/noninvolved skin and augmented in the degree of expression in psoriatic lesions. Intraepidermal and dermal angiocentric T cells in the initial and active lesions belonged predominantly to the CD3+, CD4+, CD45RO+, lymphocyte function-associated antigen-1+, and very late antigen-4+ helper-inducer/memory subset. The number of these memory T cells around SPMV was significantly correlated with the degree of expression of E-selectin and VCAM-1 on SPMV in the initial lesion. Intraepidermal memory T cells in the active lesion showed significant correlation with the expression of E-selectin and VCAM-1 on PMV. The CD8+ cells were dominant in the epidermis of the involuting phase. None of the adhesion molecules studied seemed to play a role in infiltration of this cell type.

CONCLUSIONS

The results suggest (1) participation of memory T cells in the formation of the initial and active stages of psoriatic plaques, and (2) E-selectin and VCAM-1 on endothelium as the critical adhesion molecule for initial trafficking of memory T cells into psoriatic lesions.