Evaluation of lymphatic and blood vessel density in psoriatic skin

Background and Design: Angiogenesis plays a significant role in the physiopathology of psoriasis. Since psoriasis is considered to be an angiogenesis-dependent disease, lymphatic vessels have received little attention in psoriasis research. The results of the studies on lymphatic vessel density in psoriasis plaques varies by the detection procedure and the results are contradictory. The purpose of this study was to determine lymphatic vessel density using a novel lymphatic vessel-specific marker D2-40 and to compare it with general vessel density as determined by CD34 immunohistochemical staining in psoriatic plaques. Materials and Methods: Thirty-seven untreated patients with psoriasis (16 men, 21 women) and 16 healthy control subjects were included in the study. Biopsy specimens taken from the subjects were evaluated by immunohistochemistry using D2-40 and CD34 antibodies to show the lymphatic and blood vessels. Results: We found a significantly increased number of lymphatic blood vessels stained with D2-40 in both papillary and reticular dermis in psoriatic plaques as compared to control group (p=0.007 and p=0.001, respectively, Mann-Whitney U test). The number of lymphatic vessels stained with D2-40 in reticular dermis were significantly higher than the number of lymphatic vessels in papillary dermis (p=0.001, Wilcoxon test). The number of blood vessels stained with CD34 were higher in both reticular and papillary dermis when compared to controls (p=0.000 and p=0.008, respectively, Mann-Whitney U test). Conclusion: Our study demonstrated marked immunostaining of CD34 and D2-40 vessels in psoriatic plaques when compared to control group. Increased numbers of lymphatic and blood vessels in psoriasis suggest that lymphangiogenesis as well as angiogenesis may contribute to the pathogenesis of psoriasis. (Turkderm 2012; 46: 191-5)