Serum free light chain levels in children are higher in females than in males during eosinophilic esophagitis

RATIONALE: Eosinophilic esophagitis (EoE) is an emerging disease worldwide, characterized by an eosinophilic infiltration of the esophageal wall. EoE is closely associated with male gender and allergic disorders, such as food allergy, eczema and asthma. The objective was to investigate a cohort of 28 children with EoE for the distribution of established and newly explored allergy markers, including immunoglobulin free light chains (IgfLC). METHODS: Serum cow's milk-specific IgE, thymic stromal lymphopoietin (TSLP), thymus- and activation-regulated chemokine (TARC/ CCL17) and Ig-fLC were analysed in a cohort of 21 boys (age 6.7 years ± 4.2 SD) and 7 girls (age 8.2 years ± 5.6 SD) suffering from EoE as diagnosed by esophageal biopsy (eosinophils > 30/ high power field). RESULTS: Cow's milk specific IgE levels were elevated when compared to clinical reference values in 9/21 (42.9%) males and 4/7 (57.1%) females. TARC was elevated in 1/21 males (4.8%) and TSLP in 4/21 males (20%) which was not the case in any female within this cohort (ns). Kappa Ig-fLC was elevated in 2/21 (9.5%) males versus 4/7 (57.1%) females (p=0.008) and lambda Ig-fLC was elevated in 1/21 (4.8%) males versus 5/7 (71.4%) females, (p=