| Although the pathogenesis of psoriasis and lichen planus are not yet clear, there are several features of the two diseases that suggest an immunologicalry mediated process mediated by T cells infiltrating into the epidermis. Psoriasis is characterized in lecional skin by hyperpro-liferation and altered differentiation of epidermal keratinocytes, neo-vascularization resulting from vascular proliferation, and invasion of inflammatory cell in both epidermis and dermis. Increasing evidence suggests an important function of CD44 isoforms, leukocyte function associated antigen ( GD11a) , in regulating T lymphocyte/ keratino-cytes, cell/menbrance and cell matrix interactions, that are essential for coordinated epidermal proliferation and differentiation as well as neovascularization. Additionally, adhesion molecules were character-ized as receptors for signal transduction processes, exerting effect such as regulation of cell proliferation and enzyme activise. The CD44 fami-ly of adhesion glyoproteins which that acts as a receptor for hyaluronan is rather variable as a result of various post - translational modifica-tions of the standard molecule. GD11a is exclusively expressed on leu-kocytes and interacts with its ligands ICAM - 1, - 2, and - 3 to pro-mote a variety of homotypic and heterotypic cell adhesion events re-quired for normal and pathologic functions of the immune systems.Materials and methodsAfter informed consent by the patients, tissue samples from the arm, face, chest or trunk were derived from chronic plaque type psori-asis and lichen planus diagnosed in our department. Biopsies from le-sional and corresponding nonlesional psoriatic skin areas were taken from all the psoriatic patients. Biopsies were immediately snap frozen in liquid nigtrogen, embedded in OCT compound and stored at -70. A total of 25 psoriasis(16 males, 9 females) and 18 lichen pla-nus (10 males, 8 females) were enrolled in the study. Among psoria-sic patients, psoriasis vulgaris were 20 case and erythrodermic psoria-sis were 5 cases. In addition, 10 cases normal skins were used as con-trol.Immunohistochemistrical staining was performed on frozen sec-tions: 1. Tissue sections(6(mm) were cut with a cryostat at -25. 2. Frozen sections from normal and lesional skins were fixed in ace-tone at room temperature for 5 min. 3. Tissue sections were washed three times for 5 min each, in PBS. 4. Tissue sections were blocked with 0.3% H202 for 30 min. 5. Washed in PBS as above. 6. They were incubated for 37 1 hour with a primary antibody from mouse CD44s, CD44v4/5, CD44v6, CDlla and CD3 or control deprived primary antibody. 7. Washed in PBS as above. 8. The sections were incubated for 37 30 minutes with tow -steps?Anti -mouse Detec-tion Reagent. 9. Washed in PBS as above. 10. They were covered with AEG and examined with a fluorescence microscope.ResultsCD44s: Immunoreactivity for CD44s was almost consistently de-tected in all cell layers of the epidermis except the stratum granulosum in lesional psoriatic, nonlesional psoriatic, lichen planus and normal skins. Epidermal CD44s immunostaining was slightly pronounced in basal cell layers while no observation in the suprapapillar layer, a pro-portion of inflammatory cell and endothelial cells were labelled as well. Staining of inflammatory cell and endothelial cells was increased in lesional psoriatic as compared to nonlesional psoriatic or normal hu-man skin.CD44v4/5 and CD44v6: Labelling pattern of MoAb directed a-gainst CD44v6 and CD44v4/5 were in the epidermis comparable to the staining pattern for CD44s in lesional psoriatic, nonlesional psoriatic, lichen planus and normal skins, but staining intensity for CD44v6 was stronger as compared to staining intensity for CD44s, CD44v4/5 was slighter than CD44s. In the dermal compartment, inflammatory cells and endothelial cells revealed no immunoreactivity for CD44v6 and CD44v4/5.GD11la: Increased numbers of cell staing with the monocyte marker GD11la were also presention the band of inflammatory cell as well as being sca...
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