Assessment of serum levels of IgE in psoriasis: the relationship with clinical types of the disease

Background: Although it is believed that psoriasis vulgaris is a prototypic T helper 1 (Th1)- associated autoimmune disease, elevation in serum IgE in several cases of psoriasis has been reported. These observations suggest a possible shift from a Th1 to a Th2 cytokine response. Objective: To assess serum concentrations of total IgE in different types of psoriasis. Patients and methods: The study included 90 psoriatic patients (30 patients with chronic plaque psoriasis, 30 with erythrodermic psoriasis, and 30 with pustular psoriasis) and 30 healthy controls. Serum IgE levels were measured by the ELISA technique in the sera of all participants. The duration of psoriasis, the Psoriasis Area and Severity Index severity scoring, and the number of relapses were recorded in each patient. Results: The serum IgE level showed a statistically highly significant elevation in cases compared with controls (P≤0.01). A statistically highly significant difference was found between the four groups with regard to the median of the total serum IgE (P≤0.01), being the highest in erythrodermic psoriasis followed by pustular psoriasis, chronic plaque psoriasis, and then controls. A significant positive correlation was found between the total serum level of IgE and the Psoriasis Area and Severity Index score, the duration and the number of relapses in erythrodermic psoriasis only. Conclusion: The serum IgE level is significantly elevated in erythrodermic psoriatic patients, which may denote a shift from Th1- to Th2-directed immune mechanism.