Background and aim
Psoriasis is a chronic inflammatory skin disease associated with systemic inflammation and a severe negative impact on the affected patients’ lives. Proteins play a central role in the inflammation and structural changes in psoriasis (1). We performed a systematic review of proteomic studies in psoriasis with the purpose to identify differentially expressed proteins (DEPs) reported across multiple studies. Here, we present the core set of differentially expressed proteins in psoriasis which we defined as DEPs reported in multiple studies in both blood and lesional skin from patients with psoriasis compared with healthy or non-lesional equivalents.
Methods
We searched PubMed, EMBASE and Web of Science using the following search string: “psoria* AND proteom*”. Eligible studies had to quantify more than nine proteins and perform a statistical test to identify DEPs (i.e. not only evaluate fold-changes). We screened lists of DEPs from the included studies to identify the proteins that were reported to be either upregulated or downregulated in at least two studies within one comparison (e.g. lesional versus non-lesional skin).
Results
We identified 772 studies of which 30 were included reporting a total of more than 5000 DEPs. From these, 426 DEPs were upregulated in psoriasis across multiple studies whereas 90 DEPs were downregulated. We identified 14 upregulated proteins reported in both psoriatic skin AND blood as the core set of dysregulated proteins in psoriasis including proteins S100-A8 and S100-A9 involved in the interleukin 17-signalling pathway, tissue-protecting elafin and the anti-inflammatory interleukin 1 receptor antagonist. Additionally, some of the upregulated proteins are regulators of gene transcription and RNA translation.
Conclusion
The identified core set of differentially expressed proteins in skin and blood from patients with psoriasis consists of 14 proteins involved in inflammation/anti-inflammation, tissue structure and regulation of DNA transcription/RNA translation.