Predictors of Interleukin-33 and Thymic Stromal Lymphopoietin levels in cord blood (Lay summary)

Ashley-Martin J, Dodds L, Arbuckle TE, Levy AR, Platt RW, Marshall JS. Pediatric Allergy and Immunology. 2015;26(2):161-7. doi: 10.1111/pai.12340

Previous studies have looked at the role of two immunological biomarkers – the cytokines thymic stromal lymphopoietin (TSLP) and interleukin-33 (IL-33) – in allergic responses, specifically the development of childhood allergic diseases (e.g., asthma, allergies, atopic dermatitis). (Note: cytokines are small proteins that are important in cell signalling). However, these two substances have not been studied during the crucial period of fetal immune system development. The main objective of this study was to identify prenatal predictors of TSLP, IL-33, and a third biomarker, immunoglobulin E (or IgE, an antibody component of the immune system) in umbilical cord blood samples from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study.

The researchers in this study used a sample consisting of 1,254 women in the MIREC Study who had a singleton, term birth with an umbilical cord blood sample. They then examined associations among the TSLP, IL-33, and IgE biomarkers, and found that TSLP and IL-33 were more strongly correlated with each other than with IgE.

Next, in their effort to identify possible predictors of elevated (i.e., higher than normal or higher than expected) levels of these biomarkers, the researchers found that maternal allergy, exposure to heavy street traffic, and elevated birth weight were significantly associated with elevated levels of both TSLP and IL-33 in umbilical cord blood. On the other hand, maternal age and female infant sex were inversely associated with elevated levels of IgE – i.e., a lower maternal age and a lower probability of the infant being female were associated with these elevated IgE levels. Interestingly, TSLP and IL-33 cord blood levels were also associated with maternal characteristics indicative of inflammation.

These findings support the concept that both TSLP and IL-33 may play a vital role in the development of childhood allergic diseases such as asthma and atopic dermatitis, and highlight the need for further research into the value of umbilical cord blood IL-33 and TSLP levels as predictors of childhood allergy.