Relationship between the Degrees of Itch and Serum Lipocalin-2 Levels in Patients with Psoriasis.

BACKGROUND: Lipocalin-2 (LCN2), a protein secreted mainly by activated neutrophils, has been associated with neurodegeneration, obesity, and inflammatory responses. Serum LCN2 concentration has been reported elevated in patients with psoriasis, but lower in patients with atopic dermatitis (AD). Spinal astrocyte-derived LCN2 was found to be involved in enhancement of itch in a mouse model of AD. However, the relationship between LCN2 and itch in patients with psoriasis has not been determined. Objective. This study examined the correlation between serum LCN2 levels and the degrees of itch in patients with psoriasis. METHODS: Serum LCN2 concentrations were measured by enzyme-linked immunosorbent assays (ELISA) in patients with psoriasis and AD and in healthy controls. The degree of itch was assessed using a visual analog scale (VAS), and disease severity was determined by measuring psoriasis area and severity index (PASI) and scoring atopic dermatitis (SCORAD). Correlations among serum LCN2 level, VAS, PASI, and SCORAD were analyzed statistically. We further examined the serum LCN levels in psoriasis patients before and after biological treatment. RESULTS: Serum LCN2 concentrations were significantly higher in patients with psoriasis and AD than those in healthy controls. In patients with psoriasis, serum LCN2 concentrations were significantly correlated with VAS, but not with PASI. In contrast, serum LCN2 concentrations did not correlate with VAS or SCORAD in patients with AD. Serum LCN2 levels in psoriasis patients significantly decreased after the biological treatment along with improvement of VAS. CONCLUSION: Serum LCN2 concentration is associated with the degree of itch in patients with psoriasis, suggesting that serum LCN2 may be a useful clinical marker for itch in psoriasis.

Exacerbation of atopic dermatitis symptoms by ustekinumab in psoriatic patients with elevated serum immunoglobulin E levels: Report of two cases.

Psoriasis is a chronic inflammatory skin disease mainly mediated by a T-helper cell subset, Th17 cells. Recently, increased levels of total serum immunoglobulin (Ig)E have been reported in a subset of psoriatic patients. Ustekinumab (UST) is one of the most commonly used biologic agents for the treatment of moderate to severe plaque psoriasis, and a previous report also documented effectiveness of UST for psoriatic patients with high serum IgE levels. We experienced two psoriatic patients with high serum IgE levels, in whom UST completely improved psoriasis but paradoxically provoked or exacerbated atopic dermatitis (AD)-like symptoms. This reciprocal phenomenon suggests the shift of Th balance toward Th2, along with altered profiles of inflammatory cytokines. It appears prudent to consider the possibility of such adverse effects when treating psoriatic patients with UST with concomitant AD symptoms, a history of AD or high serum IgE levels.