493 Immunogenetic profiling of anatomically-distinct areas of psoriasis

Abstract

Practitioners have recognized that anatomic location is an important feature that defines clinically distinct subtypes of psoriasis. Currently, there is little known about how scalp and palmoplantar psoriasis differ biologically from conventional plaque psoriasis of the trunk and proximal extremities. We hypothesize that conventional plaque, scalp, and palmoplantar psoriasis may represent distinct subtypes of psoriasis with different immunogenetic profiles. We isolated lymphocytes from 4 millimeter punch biopsies of anatomically-distinct psoriatic lesions and healthy control skin and used flow cytometry to measure the percentage of CD4+ T effector cells, CD8+ T effector cells, and T regulatory cells (Tregs) in these lesions. We assessed for cellular production of cytokines such as IL-17, TNF-a, IFN-g, IL-22, IL-13. We also performed RNA-sequencing of anatomically-distinct regions of psoriasis and healthy control skin. Compared to healthy controls, interim results show a trend towards increased Tregs in psoriatic scalp compared to controls. In psoriatic scalp there was also a significant increase in the percentage of T cells producing IL-17A (CD4+, CD8+), TNF-a (CD8+), IFN-g (CD4+), and IL-22 (CD8+) compared to control skin. In conventional plaque psoriasis of the trunk and proximal extremities there was a significant increase in the percentage of T cells producing IL-17A (CD4+) and TNF-a (CD4+, CD8+) compared to control skin. When comparing psoriatic scalp versus conventional plaque we observed a trend in increased IL-22 production in the scalp. Analysis of palmoplantar psoriasis and RNA-seq data is ongoing. Our goal is to define the immunogenetic profiles of these subtypes of psoriasis in order to identify the most active biological pathways in each psoriasis subtype.