Serum immunoglobulin free light chain levels are higher in girls than boys during eosinophilic oesophagitis

Aim Eosinophilic oesophagitis ( EO ) is an emerging worldwide disease, closely associated with male gender and allergic disorders. This study investigated the distribution of allergy markers in a cohort of children with EO . Methods We analysed allergy markers in 91 children (62 males and 29 females) with EO and a control group of 45 age‐matched children who had non‐ EO gastrointestinal allergic symptoms. The markers analysed were serum cow's milk‐specific and hen's egg‐specific IgE, thymic stromal lymphopoietin ( TSLP ), thymus‐regulated and activation‐regulated chemokine ( TARC / CCL 17) and immunoglobulin free light chain (Ig‐ fLC ). Results In the EO group, cow's milk‐specific IgE levels were detectable in 41.9% of males and 62.1% of females and hen's egg‐specific levels in 25% of males and 26.9% of females. There was no gender difference in increased TSLP or TARC levels. Kappa Ig‐ fLC were increased in 5.6% of males and 20.8% of females (p = 0.058) and lambda Ig‐ fLC in 1.9% of males and 33.3% of females (p = 0.000). No gender differences were found in the control group. Conclusion Our findings suggest that serum TSLP might be a potential marker of EO and TARC of non‐ EO gastrointestinal food allergies. In EO , serum Ig‐ fLC appeared higher in females, adding another gender difference to the biology of EO .