Background:  Fetal programming is the notion that adverse environmental conditions in utero can cause short term survival adaptations that may have long-term consequences, such as chronic disease in subsequent lifetime. Recently, some authors reported that the increase of allergy prevalence in childhood may be linked with fetal immune development. In this regard, literature survey inspired to study the influence of two conjugated linoleic acid (CLA)-isomers (c9,t11 and t10,c12) on parameters of the immune system in pregnancy.

Methods:  Lymphocytes from allergic and non-allergic mothers, cord blood of their newborns, and the decidual layer of term placentae were isolated and cultured for 2 days and supplemented or not with relevant allergens, c9,t11 CLA, t10,c12 CLA or linoleic acid, respectively. Expression of CD69 (activation marker) and CD71 (transferrin receptor; proliferation marker) on B and T lymphocytes and T helper cell type 1 (Th1) and Th2 cytokines in culture supernatant were analyzed.

Results:  Both CLA isomers led to an increase of the IFN-γ/IL-10 ratio in supernatants of peripheral maternal and cord blood cells from allergic patients and non-allergic-control. CLA supplementation decreased IL-10 secretion of peripheral maternal and decidual lymphocytes and the portion of CD71+ maternal B cells. Linoleic acid induced a similar effect.

Conclusion:  An immunological effect of CLA on maternal and fetal lymphocyte responses could be demonstrated. It would be expected that further investigations could reveal differences in effects of CLA and linoleic acid.