Cognitive Decline and Neurodegenerative Markers in Psoriasis: The Role of APOE4 and Beta-Amyloid.

INTRODUCTION: Psoriasis vulgaris (PV) is a chronic inflammatory skin disease increasingly recognized as a systemic disorder with potential cognitive implications. Amyloid beta (Aβ) and apolipoprotein E (APOE) are key proteins involved in Alzheimer's disease (AD) and neurodegeneration. OBJECTIVES: This study investigated the relationship between PV, cognitive function, and serum levels of Aβ and APOE4. METHODS: This case-control study was conducted on 80 participants: 50 PV patients and 30 age- and sex-matched controls. Clinical assessments included Psoriasis Area and Severity Index (PASI). Depression severity was assessed with Beck Depression Inventory-II (BDI-II), while cognitive function was evaluated using Montreal Cognitive Assessment (MoCA). Serum APOE4 and Aβ levels were measured using ELISA. RESULTS: Patients with PV exhibited significantly higher levels of APOE4 (1125.5 ± 232.1 ng/ml vs. 821.8 ± 266 ng/ml, P<0.001) and Aβ (21.4 ± 2.2 ng/ml vs. 18.7 ± 1.4 ng/ml, P<0.001) compared to controls. ROC analysis identified APOE4 (AUC=0.80, P<0.001) and Aβ (AUC=0.86, P<0.001) as significant predictors of PV. MoCA scores were significantly lower in PV patients (median=22 vs. 28, P<0.001), particularly in those with severe disease. APOE4 and Aβ levels negatively correlated with cognitive function (r= -0.418, P=0.003), and (r= -0.399, P=0.004) respectively. CONCLUSIONS: PV is associated with elevated Aβ and APOE4 levels, potentially linking chronic inflammation to neurodegeneration. The observed cognitive dysfunction in PV individuals underscores the importance of integrating neurological assessments into routine clinical evaluations.