Modulation of in vivo and in vitro cytokine production over the course of pregnancy in allergic and non-allergic mothers

Cytokines secreted during pregnancy may influence immune development of the foetus. This study aimed to determine if maternal allergy alters patterns of systemic cytokine production throughout and after pregnancy. Maternal plasma cytokines and allergen-specific production of interleukin (IL)-10, IL-13 and interferon (IFN)-gamma were measured in allergic (n = 63) and non-allergic (n = 70) pregnant women who had a full set of sequential peripheral blood samples collected at 20-, 30-, 36-wk gestation and 6-wk post-partum. Maternal allergy was strictly defined by both allergen sensitization and doctor-diagnosed asthma, eczema or rhinitis. IL-13 responses to allergen were higher for allergic mothers at all time-points (20 wk: p < 0.001; 30 wk: p = 0.001; 36 wk: p < 0.001; post-partum: p < 0.001). For the non-allergic group, IL-13 levels to house dust mite decreased from 20- to 36-wk gestation (Friedman anova p = 0.012) and were significantly lower at 36 wk compared with post-partum (p = 0.002). In contrast, IL-13 production by allergic mothers did not change from 20 wk through to post-partum. For both allergic and non-allergic mothers, in vitro IFN-gamma production was lower at all pregnancy time-points compared with post-partum levels. Allergic women had an increased propensity for peripheral blood allergen-specific T helper-2 responses during pregnancy, and failed to downregulate these responses in comparison with non-allergic women. This may be a factor that contributes to the increased risk of atopy in infants born to allergic mothers.