Immunophenotyping of dendritic cells in lesional, perilesional and distant skin of chronic plaque psoriasis.

Psoriasis affects 2.7% of the world's population. The sequence of these events remains controversial. Because antigen presenting is necessary for T-cell activation, dendritic cells may be involved in the pathogenesis of psoriasis. To investigate their role, we examined immunophenotyping of different dendritic cells and their distribution and numbers in psoriasis patients. Immunohistochemistry of CD1a, CD11c, CD86 and BDCA2 were performed using paraffin-embedded tissue obtained from a total of 45 patients with psoriasis. Samples were taken from the lesion, perilesional and distant skin and normal skin obtained from 10 control cases. There were marked increase in the number of positive CD1a, CD11c, CD86 and BDCA2 cells in perilesional and the psoriatic skin when compared to the distant skin and they were the least in the normal control skin. So different dendritic cells subsets have a very important role in psoriasis pathogenesis especially in initiation of the plaque in the perilesional skin.