Examination of bcl-2 and p53 expressions and apoptotic index by TUNEL method in psoriasis

Psoriasis is characterised by hyperproliferation and by aberrant differentiation. Blockage of the normal apoptotic process is one of the factors implicated in the pathogenesis. To determine the apoptotic features by using TUNEL method and also bcl-2 and p53 expressions in psoriatic epidermis. Biopsies of 35 patients with psoriasis vulgaris and 14 normal skin were evaluated. Apoptotic cells were detected using the dUTP nick-end labelling assay; bc1-2 and p53 expressions were assessed by using immunohistochemical techniques. A semi-quantitative grading system (HSCORE) was used for comparison. Bcl-2 was strongly expressed in basal keratinocytes of normal skin, while no expression was observed in 13 (37.2%) of the psoriatic samples and it was weakly expressed in the spinous cell layer of 22 (62.8%) samples. Moderate p53 expression was observed in the psoriasis group, while it was weak in the control. The percentage of TUNEL positive cells were significantly increased in the psoriasis group (65 +/- 2.30) when compared with the control (32.84 +/- 7.16). Apoptotic index besides bc1-2 and p53 expressions in psoriasis differ from normal epidermis. Down-regulation of bc1-2 is consistent with the dynamics of psoriasis but increased TUNEL positive cells and p53 expression has not been fully elucidated yet.