Measurement of Serum Interleukin 24 Specific Immunoglobulin E in Chronic Spontaneous Urticaria and Atopic Dermatitis Patients

Abstract

Atopic dermatitis is a common skin condition with significant associated social and financial burden. It affects adults and children with worldwide prevalence rates of 1–20%. It can have an acute course or become chronic, lasting longer than 6 weeks and in many cases persists several months or years. The pathophysiology of atopic dermatitis is complex and multifactorial, involving elements of barrier dysfunction, alterations in cell mediated immune responses, IgE mediated hypersensitivity, and environmental factors. The imbalance of Th2 to Th1 cytokines observed in atopic dermatitis can create alterations in the cell mediated immune responses and can promote IgE mediated hypersensitivity, both of which appear to play a role in the development of atopic dermatitis. Chronic urticaria is defined as the presence of urticaria for a period exceeding 6 weeks, assuming symptoms for most days of the week. It is divided into chronic inducible urticaria and chronic spontaneous urticaria, previously termed chronic idiopathic urticaria. CSU signifies that patients can experience urticaria independent of any exogenous stimulus even if one can define circumstances that may worsen symptoms. In most cases, it is a self-limiting disorder, persisting for 2 to 5 years in most cases, although 20% of patients suffer for more than 5 years. Several theories were proposed to explain the pathogenesis of CSU, of which emerges the autoimmune theory. Patients express autoreactive IgE species that activate skin mast cells in CSU . The autologous serum skin test (ASST) is used as a non-specific screening test to evaluate the presence of histamine-releasing factors in serum . Interleukin-24 is one of the IL-10 cytokine families. It exhibits several functions as an autoimmune effect in many diseases of immune origin. Therefore IL-24 SP IgE was studied for its potential role in the pathogenesis of diseases such as psoriasis, rheumatoid arthritis Our study aimed to evaluate the presence and percentage of serum IL-24 SP IgE in chronic spontaneous urticaria and atopic dermatitis. This case control study was conducted on 20 AD patients, 20 CSU patients, and 20 apparently healthy matched aged and sex controls. Included subjects were subjected to full general and dermatological examination, calculation of AD score for AD patients using SCORAD and calculation of urticaria activity score seven (UAS7) for CSU patients. Autologous serum skin test and measurement of total serum IgE and IL-24 SP IgE in all subjects were also performed.