Table 2.

Studies evaluating candidate biomarkers in psoriasis through immunohistochemical tissue analysis.

Author, Year	Study Design	Population	Comparison (Control)	Technique	Biomarker Levels/ Outcomes	p
[54]	Cross-sectional	Chronic plaque psoriasis patients n = 36	Normal individuals attending plastic surgery outpatient clinic n = 40 Uninvolved skin from 10 patients	Skin biopsy-3 mm punch, immunohistochemical staining of endocan	Upregulation of endocan in the involved psoriatic skin (63.9% in the epidermis and 36.1% in the dermis) and absence of its expression in uninvolved skin biopsies
					Significant difference between psoriatic and normal skin in epidermal and dermal endocan expression	Epidermal endocan expression p = 0.003, dermal p < 0.001
					Strong epidermal expression of endocan in cases affecting the trunk compared to cases affecting extremities	p = 0.023
					Strong and moderate intensity of endocan expression by epidermis associated with marked acanthosis	p = 0.038
					Positive dermal endocan expression associated with marked parakeratosis and moderate angiogenesis	p = 0.018 parakeratosis p = 0.011 angiogenesis
[57]	Cross-sectional	Chronic plaque psoriasis n = 30	Normal individuals n = 20 Perilesional psoriatic skin n = 30	Immunohistochemical evaluation of Plexin-B2	Significant overexpression of Plexin-B2 in epidermal keratinocytes from controls to perilesional and lesional skin	p < 0.001
					Overexpression of Plexin-B2 in dermal inflammatory cells of lesional psoriatic skin compared to control	p < 0.001
					Positive correlation between Plexin-B2 H-score values in the lesional epidermis and PASI scores and in dermal inflammatory cells and PASI score	p < 0.001 p < 0.026
					High Plexin-B2 expression in lesional epidermis associated with parakeratosis	p < 0.016
					High Plexin-B2 expression in lesional dermal inflammatory cells associated with acanthosis and hyperkeratosis	p = 0.006 p < 0.001
[61]	Cross-sectional	Chronic plaque psoriasis n = 30	Normal individuals n = 20 Perilesional psoriatic skin n = 30	Immunohistochemical analysis of Smad7	Smad7 was progressively upregulated in proliferating keratinocytes from controls to perilesional and lesional skin	p < 0.01
					Dermal inflammatory cells showed up-regulation of Smad7 expression in lesional skin	p < 0.10
					Positive correlation of Smad7 expression with psoriasis severity	p < 0.012
[55]	Cross-sectional	Chronic plaque-psoriasis n = 11	Healthy n = 8 Perilesional n = 11	Immunohistochemistry -analysis of perforin, T, and NK-cells subsets	Significant increase in CD4+ and CD8+ cells in psoriatic skin compared with perilesional and healthy skin	p < 0.01 p < 0.001
					Expression of CD16+ NK cells lower in lesions compared with healthy skin	p < 0.05
					Perforin expression was significantly enhanced in the epidermis of psoriatic lesions compared to the dermis	p < 0.01
[56]	Cross-sectional	Chronic plaque psoriasis n = 15	Normal skin n = 5	Immunohistochemical study	In the epidermis of psoriatic skin, HIF-1α was diffusely expressed
					Positive correlation between HIF-1α and VEGF in psoriatic skin	p = 0.010
					Total MMP-2 expression of healthy skin was significantly lower compared to psoriatic skin	p = 0.0001
					Positive correlation between VEGF and MMP-2 in psoriatic skin	p = 0.046
					Decreased expression of Tissue Inhibitor of Metalloproteinase-2 (TIMP-2) and TIMP-1 in psoriatic skin	p = 0.0001
[62]	Longitudinal	Chronic plaque psoriasis n = 27	Normal skin n = 20	Antimicrobial peptides (AMP) immunohistochemistry	The Human Beta Defensin-1 (hBD-1) level was higher in psoriasis patients than in healthy controls	p = 0.001
					No difference in hBD-1 and hBD-2 levels before and after phototherapy in patients’ group
[60]	Longitudinal	Chronic plaque psoriasis n = 31 (tissue bank)	Normal skin n = 32	Immunohistochemistry Fib3, Western blot analysis, RT-PCR for Fib3mRNA expression	Fib3 overexpressed in the lesional skin; levels positively correlated with psoriasis progression	p < 0.05
					Fib3 upregulated VEGF expression in endothelial cells	p < 0.05
					Topical/ subcutaneous injection of Fib3 ab decreased PASI and VEGF expression in imiquimod-treated mice	p < 0.05 for both
[63]	Cross-sectional	Chronic plaque psoriasis n = 24	Healthy controls n = 12	Immunohistochemical serotonin expression	Serotonin expression was higher in psoriatic plaques compared to normal skin	p = 0.018
					H score of serotonin expression was higher in cases with absent Granular Cell Layer (GLC) and in cases with strong epidermal inflammation	p = 0.011 p = 0.035