Effect of etretinate on the distribution of Langerhans cells and T. lymphocytes in psoriatic skin

Assessment of epidermal dendritic cell markers and T-lymphocytes in psoriasis

Epidermal dendritic and T-cell counts have been performed in lesional and non-lesional skin from 35 psoriatic patients. The aims were to investigate absolute changes and interrelationships between these cellular elements in psoriasis and to explain apparent discrepancies between these results and reports in the literature. In non-lesional skin, the most frequently expressed dendritic cell marker was CD1a. HLA-DR+ and alpha-mannosidase+ dendritic cells were approximately 50 per cent and S100+ cells were 25 per cent as frequent. T-lymphocytes were rare, CD4+ cells predominating. In lesional psoriatic epidermis, there was a definite increase (approximately two-fold) in the absolute number of CD1a+ dendritic cells. This differs from the conclusions from the majority of previous studies. However, when cell counts were expressed per unit area of vertical section, there was a decrease in CD1a+ cells in lesional skin, which is an explanation for this discrepancy. There was a greater increase in absolute HLA-DR+ cell counts, so that the numbers of cells expressing CD1a and HLA-DR were similar in lesional skin. S100 expression increased proportionately with CD1a+, but there was no absolute increase in alpha-mannosidase+ cells, which might represent a separate sub-population of dendritic cells. The greatest cellular increase was in T-lymphocytes, particularly CD8+. In lesional skin, direct correlations have been demonstrated between epidermal thickness, HLA-DR+ dendritic cells and T-lymphocytes, particularly CD8+ cells. We would suggest that the present method of quantification is of value for the analysis of absolute changes in epidermal infiltrates, particularly psoriasis, and could be applied to other epidermal pathologies.

Successful treatment of a patient with Reiter's syndrome and acquired immunodeficiency syndrome using etretinate

In a 30-year-old homosexual man with a 3-year history of localized psoriasis, an oligoarthropathy and severe cutaneous lesions of Reiter's syndrome developed 6 months after acquired immunodeficiency syndrome (AIDS) was diagnosed. Reiter's syndrome and psoriasis may be a continuum of similarly expressed cutaneous diseases that develop in genetically predisposed individuals. We discuss the possible involvement of T lymphocytes and Langerhans cells in the cutaneous lesions of AIDS patients with psoriasis and Reiter's syndrome. In these AIDS patients, skin disease tends to be severe and recalcitrant to conventional therapy. Etretinate plus topical fluorinated steroids was an excellent treatment, producing near clearance of skin lesions and significant improvement in the oligoarthropathy.