Serum SCCA as a biomarker for assessing severity and monitoring treatment response in psoriasis

While clinical examination remains the diagnostic cornerstone for psoriasis, there is a relative lack of objective, quantitative biomarkers to complement clinical assessment for tracking disease severity and monitoring therapeutic response. We evaluated serum SCCA's utility in identifying psoriasis and assessing its severity across demographic (gender, age) and clinical (comorbidity) subgroups, and its association with therapeutic responses.

A total of 181 adult (≥18 years old) patients with newly diagnosed psoriasis were included in the disease group; 385 patients with other skin-related diseases and 658 healthy adults were included as controls. Patients diagnosed with tumors or renal failure were excluded. Serum SCCA was determined using Roche Cobas e 801 analyzer (Roche, Basel, Switzerland). Dynamic analysis was performed to evaluate the significance of serum SCCA in monitoring psoriasis treatment response.

Serum SCCA levels in psoriasis patients were mainly affected by gender and concomitant diseases. Notably, SCCA demonstrated high diagnostic accuracy (AUC: 0.89-0.90) in patients with comorbidities, with sex-specific cutoffs. The cutoff value of serum SCCA for identifying severe psoriasis was 2.64 ng/mL with an AUC greater than 0.9 and an NPV over 95 %. Serum SCCA levels were significantly correlated with the psoriasis area and severity index (PASI) and body surface area (BSA) both before and after treatment. The median decrease rate of serum SCCA was close to 50 % at >5 days post-treatment and 60 % at >10 days post-treatment.

Serum SCCA shows promise as a reliable, complementary biomarker for the severity assessment and treatment monitoring of psoriasis. Its application for identification purposes should be stratified by sex and comorbidities.