Serum IgD Levels in Allergic Children with Gastrointestinal Manifestations

A large number of studies investigating various biomarkers for allergy have been published over the past decades. To this date, no single or specific biomarker for allergy has been identified. Therefore, we examined markers of inflammation and immunoglobulins in children with allergic symptoms, among which children with GI allergy, in an attempt to find new and indicative markers for GI allergy. In the present study, total serum levels of immunoglobulin (Ig)D, CM-lgE, Ig-free light chain (Ig-fLC) kappa and lambda, thymic stromal lymphopoietin (TSLP), thymus and activation-regulated chemokine (TARC/CCL17) and galectin-9 were analyzed on 117 atopic infants and children, divided into different allergic manifestations: asthma (n=7), atopic dermatitis (n=56), eosinophilic esophagitis (n=20) and gastrointestinal (GI) allergy (n=34). Elevated levels of serum IgD, without the presence of IgE, was found in children with GI allergy. Serum IgD did not correlate with other laboratory parameters of atopy such as serum cow's milk-lgE, Ig-fLC, TSLP, TARC and galectin-9. In conclusion, serum IgD is elevated in children with GI allergy, in the absence of IgE, and can be considered as a new indicative marker for GI allergy, however, its exact role in the pathogenesis of atopy awaits further studies.