Reanalysis of the immunological characteristics of scalp psoriasis: a cross-sectional study using Olink proteomics.

OBJECTIVE

To analyze the molecular profile of adult patients with Scalp psoriasis (SP).

METHODS

We assessed 92 inflammatory biomarkers in lesional scalp skin from SP patients (n = 20) and demographically comparable healthy controls (HCs, n = 12) using Olink high-throughput proteomics, and investigated the expression of Th2-type cytokines using ELISA in an independent cohort (contains 11 SP patients and 5 HCs).

RESULTS

We identified 28 differentially expressed proteins (DEPs) in lesional SP compared to HCs (FC ≥ ±1.2, adjusted p-value <0.05). We observed that SP exhibits a Th1/Th17/IL-12/IL-23-dominant molecular signature. GO clustering and KEGG pathway analyses demonstrated close interrelationships among cytokines, chemokines, and their receptors during the psoriatic inflammatory cascade. Moreover, our results indicated a down-regulation of Th2-type molecules in the SP group, evidenced by significantly reduced levels of IL-4 and IL-5. Notably, these decreases were negatively correlated with the scalp-specific Investigator's Global Assessment (ss-IGA) scores (IL-4: r = -0.78, p < 0.01; IL-5: r = -0.65, p < 0.05), which may lead to an imbalance characterized by an enhanced Th1/Th17/IL-12/IL-23 inflammatory response.

CONCLUSION

This proteomic profile provides a new perspective on the immunological pathogenesis of SP, suggesting an imbalance between Th2 and Th1/Th17/IL-12/IL-23 responses.