Methods: Serum was collected from 20 subjects with moderate-to-severe AD, 20 subjects with CD, 12 subjects with moderate-to-severe PS, and 10 healthy controls with no history of skin disease. Protein expression was evaluated by SOMAscan™, Singulex®, and multiplex technology. Expression in AD, CD, and PS serum was compared to healthy controls for statistical significance (fold change ≥ 1.5 and false discovery rate < 0.05) and lists compared between diseases to identify unique proteomic signatures.
Results: This study identified 7 proteins (Up Regulated: C5a, PARC, LBP, CRP, ILT-4; Down Regulated: CAMK2B, Carbonic anhydrase 6) that were similarly modulated in all inflammatory skin diseases compared to healthy controls. Additional comparisons with serum from healthy controls revealed significant modulations in a total of 25, 5, and 64 proteins in subjects with AD, PS, and CD, respectively. Protein signatures were further refined by comparing between inflammatory skin diseases. This resulted in a unique signature of increased IgE, CCL17/TARC, and CCL22/MDC in AD; which significantly correlated (p<0.05) with disease severity.
Conclusions: This study suggests unique proteomic signatures in the sera may potentially distinguish between inflammatory skin diseases despite similar epidermal barrier disruption and epithelial inflammation.