Expression of 60kd Heat Shock Protein and T Cell Receptor gamma delta in Guttate and Plaque Psoriasis

Kim, Hyun Joon; Park, Eun Joo; Kim, Chul Woo; Cho, Hee Jin; Kim, Kwang Ho; Kim, Kwang Joong; Park, Hye Rim; Kim, Yong Sun

Abstract

BACKGROUND: Psoriasis is a chronic disease of the skin that appears to be of autoimmune nature. An association with throat streptococcal infections in some subtypes of psoriasis has been suggested. Heat shock protein (HSP) is known to play an important role in the immune and inflammatory responses of the skin including psoriasis. Recent studies have suggested that T-cell receptor (TCR) responds to HSP peptides.
OBJECTIVE
We aimed to investigate the role and correlation of HSP and TCR in the pathogenesis of guttate psoriasis by studying whether there is any difference in HSP60 and TCR gamma delta-positve cell expression in guttate psoriasis compared to plaque psoriasis.
METHODS
Skin biopsy specimens from patients with guttate psoriasis (n=12), patients with plaque psoriasis (n=12), and normal skin controls (n=5) were used in the study. One-half were fixed in formalin and embedded in paraffin, and the other half were snap frozen and stored. Antibodies to HSP60 and TCR gamma delta were applied immunohistochemically. An immunoreactivity intensity distribution index (IRIDI) of HSP was calculated to express the proportion of the immunoreactive cells as well as the staining intensity in different layers of the epidermis. And the expression of HSP60 was also analyzed by Western blot analysis. TCR gamma delta-positive cell counts were semiquantitatively evaluated in 3 consecutive X400 microscopic fields, which were divided into epidermis and dermis.
RESULTS
The mean IRIDI scores for HSP60 expression of guttate psoriasis were moderately higher than those for normal skin in the suprabasal layer (p<0.05), but not significantly different from normal in the other layers and plaque psoriasis. And results from Western blot analysis were similar to the mean total IRIDI scores for HSP60 expression, but there was not significant differentiation amongst the three groups. TCR gamma delta-positive cell counts in the lesions of guttate and plaque psoriasis were significantly different from normal skin (p<0.05) and TCR gamma delta-positive cell counts for guttate psoriasis were higher compared to those for plaque psoriasis (p<0.05). There was no significant correlation between HSP60 and TCR gamma delta(p>0.05).
CONCLUSION
This study suggests that up-regulation of HSP60 expression in the suprabasal layer may support the association of HSP60 in the etiology of psoriasis. TCR gamma delta may be involved in the pathogenesis of psoriasis, especially guttate psoriasis rather than plaque psoriasis, even though the correlation of HSP60 and TCR gamma delta was not significant. The mechanism of how they act to promote induction and aggravation in psoriasis remains to be elucidated.