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Summary Background Deregulation of the proteasome pathway has been shown to be involved in the pathogenesis of several inflammatory disorders. To date limited information exists on proteasome and immunoproteasome expression and activity in psoriasis skin. Objectives To investigate the potential role of proteasomes in the pathogenesis of psoriasis. Methods Thirty-six patients with psoriasis and 40 healthy subjects were included. The protein and mRNA expression levels and proteolytic activity of proteasome and immunoproteasome subunits were determined using immunohistochemistry, quantitative polymerase chain reaction and fluorogenic peptide substrate in lesional and nonlesional psoriasis skin. We additionally measured the plasmatic proteasome (p-proteasome) levels using enzyme-linked immunosorbent assay. Results We reveal an increased expression of proteasome and immunoproteasome subunits but stable mRNA levels in lesional psoriasis skin as compared with nonlesional psoriasis skin (n = 19), suggesting that proteasome and immunoproteasome expression is regulated post-transcriptionally. This proteasome overexpression was associated with a significant increase of the proteasomal chymotrypsin-like activity that was threefold higher in lesional skin than in nonlesional skin (n = 3). p-Proteasome levels were enhanced in patients with psoriasis (mean ± SEM 3960 ± 299 ng mL−1, range 1484–8987) when compared with controls (2535 ± 187 ng mL−1, range 654–6446, P

Summary Background Proteasomes, nonlysosomal proteolytic structures, are implicated in cell growth and differentiation. An abnormal expression has been described in haematopoietic malignancies and in some solid tumours. Objectives To study the plasma proteasome levels in patients with malignant melanoma (MM) using an enzyme-linked immunosorbent assay (ELISA) technique, and to compare them with the values obtained in a normal population and in patients with severe psoriasis or chronic idiopathic urticaria (CIU). Methods Plasma proteasome level was measured using a sandwich ELISA test in normal donors (n = 14), and in patients with stage I/II (n = 13), stage III (n = 6) and stage IV (n = 10) MM, severe psoriasis (n = 13) and CIU (n = 6). Tissue proteasome expression was also detected by immunohistology using a monoclonal antibody in paraffin-embedded samples of normal tissue, psoriasis skin and MM. Results In normal donors, mean ± SEM plasma proteasome concentration was 2138 ± 221 ng mL−1. Patients with stages III and IV MM exhibited a significantly higher value (3373 ± 470 ng mL−1 and 8931 ± 1232 ng mL−1, respectively). Values in patients with stage I/II MM and CIU were not significantly different from those in normal volunteers. Patients with severe psoriasis also exhibited increased values (3398 ± 374 ng mL−1) but to a lesser extent than in patients with stage IV MM. There was a significant correlation of proteasome levels with serum lactate dehydrogenase in the MM group. Tissue expression as demonstrated by immunohistochemistry paralleled these findings. The strongest expression was seen on MM slides and to a lesser extent in psoriasis samples, the weakest expression being observed in normal skin. Conclusions Proteasomes are strongly expressed in cutaneous MM; high levels of circulating proteasomes are detected in patients with metastatic MM with a high melanoma burden, and at a lesser extent in psoriatic patients, which suggests proteasomes represent a marker more of nonspecific inflammation than of early cancer.

Summary In a left-right comparative study, the Philips TL-01 sunlamp, a new UVB fluorescent lamp, was evaluated in 15 patients with symmetrical psoriasis. One half of the body was treated in a cabin containing TL-01 lamps, and the other half in a cabin containing TL-12 lamps. The patients were treated three times/week, and the study was conducted in a randomized, double-blind fashion. The percentage response of psoriatic lesions was determined on the tenth and twentieth exposures. The therapeutic effect of the TL-01 lamps was superior to that of the TL-12 lamps, and treatment was better tolerated, particularly with regard to episodes of burning. This new lamp appears to provide more effective and safer phototherapy for psoriasis.