Evaluation of involucrin expression and agnor count in psoriasis

ABSTRACT

Involucrin is one of the precursor protein of cornified cell envelop of keratinocytes. It is expressed during the later stage of keratinocye differentiation. Psoriasis is a chronic skin disease characterized clinically by erythernatous plaques corresponding to epidermal hyperproliferation. The present study was designed to identify role of involucrin in the pathogenesis of psoriasis and its different distribution pattern in keratinocytes of normal and psoriatic lesions and its relation to aregrophilic neuleolar organizer region [AgNor] count. The study was carried out on 30 cases, 15 cases were psoriasis vulgaris and the other apparently healthy individuals were considered as control. Excision biopsies were obtained from all cases, fixed in neutral buffered formalin, processed and paraffin sections were prepared on positive charged adhesive slides. A set of sections were stained by hernatoxylin and eosin [H and E], another set was conducted for immunohistochemistry procedure using involucrin monoclonal antibody and a third set was conducted for silver staining to identify nucleolar organizer region. In normal skin involucrin was noticed to be expressed in the parabasal kerationcytes in epiderm in all biopsies of the control group. However, involucrin showed mosaic expression throughout the keratinocytes. The mean AgNor count in the normal group was I .5+0.32, which was noticed to be increased in sporiasis cases [mean 4.2+0.54]. Interestingly, there was positive correlation between involucrin wide expression and increased mean AgNor count. In conclusion, wide expression of involucrin was correlated with increased proliferation potential and subsequently to the extent of psoriasis disease