Circulating Interleukin 16 (IL-16) in children with atopic/eczema dermatitis syndrome (AEDS):: a novel serological marker of disease activity

Background: Chemokines play a central role in atopic eczema/dermatitis syndrome (AEDS). Interleukin 16 (IL-16) has been described as a main cytokine involved in CD4+ cell recruitment during inflammation. Recently the influx of CD4+ lymphocytes has been related to the up-regulation of IL-16 in AEDS skin lesions. Circulating beta-chemokines (Eotaxin and RANTES) and IL-16 were investigated in children with AEDS to correlate their presence with the severity of the disease. We also measured serum levels of soluble CD30 (sCD30), a marker of Th2 immune responses related to AEDS disease activity. Methods: Serum levels of eotaxin, RANTES, IL-16 and sCD30 were measured by immunoenzymatic assay in paediatric patients with pure AEDS (pAEDS, n=39); the severity of the disease was graded by SCORAD. Fifteen children with AEDS in presence of respiratory allergy (AEDS+A), 15 with allergic asthma (A) and 20 age-matched healthy donors were investigated as control groups. Results: When compared to normals, high amounts of Eotaxin and IL-16 were detected in sera of pAEDS (P=0.002; P<0.0001), AEDS+A (P=0.02; P=0.01) and A patients (P=0.004; P=0.03) with respect to normals. Serum levels of RANTES were also elevated in pAEDS patients, significantly higher than normals (P=0.009), whereas no statistically significant differences could be detected between pAEDS and AEDS+A or A groups. IL-16 was progressively increased in the different stages of pAEDS, with a positive correlation between IL-16 and both SCORAD and sCD30 (P<0.0001). Conclusion: We suggest that IL-16 could serve as a useful marker of disease activity in childhood pAEDS.