Background Neopterin levels and kynurenine/tryptophan ratios (KTRs) increase with IFN-γ stimulation, indicating TH1 immunity, and thus might be inversely associated with asthma. Objective We sought to examine the association of maternal neopterin levels and KTRs during pregnancy with asthma in the offspring. Methods We analyzed the associations of maternal plasma total neopterin levels and KTRs in midpregnancy with asthma at age 7 years among 2883 children in the Norwegian Mother and Child Cohort Study. Asthma was classified either based on registered dispensed asthma medications in the Norwegian Prescription Database or maternal report. We calculated adjusted relative risks using log-binomial regression. Results The median gestational week of blood sampling was 18 weeks (interquartile range, 17-19 weeks). The risk of dispensed asthma medications at age 7 years was highest among children of mothers in the highest quartile of neopterin levels, whereas the risk was similar in the 3 lowest quartiles. The adjusted relative risk of dispensed asthma medications was 1.66 (95% CI, 1.16-2.38) when comparing children of mothers in the highest quartile with those in the 3 lowest quartiles. A similar association was observed for maternal report of asthma at age 7 years. When we evaluated allergic versus nonallergic asthma, neopterin levels tended to be associated with nonallergic asthma. Maternal KTR was not associated with asthma development. Conclusions Our findings indicate that high maternal levels of neopterin, a marker of cellular immune activation, during pregnancy were positively associated with asthma in offspring. Experimental studies would be needed to further elucidate underlying mechanisms.
Magnus, M. C., Karlstad, Ø., Midtun, Ø., Håberg, S. E., Tunheim, G., Parr, C. L., … Nystad, W. (2016). Maternal plasma total neopterin and kynurenine/tryptophan levels during pregnancy in relation to asthma development in the offspring. Journal of Allergy and Clinical Immunology, 138(5), 1319-1325.e4. https://doi.org/10.1016/j.jaci.2016.02.032