Pregnancy, but not the allergic status, influences spontaneous and induced interleukin-1beta (IL-1beta), IL-6, IL-10 and IL-12 responses.

In this study, we investigated how pregnancy influences cytokine production in response to stimulation of the innate and the adaptive immune system, respectively. Peripheral blood mononuclear cells (PBMCs) from allergic (n = 44) and non-allergic (n = 36) women were collected at three time-points: during the third trimester, at delivery and at a non-pregnant state 2 years after delivery. The production of interleukin-1beta (IL-1beta), IL-6, IL-10 and IL-12 was measured by enzyme-linked immunosorbent assay (ELISA) or enzyme-linked immunospot assay (ELISPOT). The spontaneous cytokine production, and the response following stimulation with agents that primarily activate the adaptive part of the immune system [phytohaemagglutinin (PHA), allergen extracts from cat and birch], or lipopolysaccharide (LPS) that activate innate immunity was measured in vitro. There was a significantly higher spontaneous in vitro production of IL-1beta, IL-6 and IL-10 by PBMCs during pregnancy than 2 years after pregnancy, and this was not affected by the allergic status of the women. Conversely, in PHA-stimulated cell cultures there was a lower production of IL-10 and IL-12 during pregnancy than 2 years after pregnancy. LPS-induced IL-6 levels were significantly lower in PBMCs obtained during pregnancy than at 2 years after pregnancy. In addition, we made the interesting observation that in allergic women total immunoglobulin E (IgE) levels were significantly lower 2 years after pregnancy compared to the levels during pregnancy. Taken together, our results indicate that while atopic allergy in women does not have a substantial effect on cytokine production, pregnancy has an obvious effect on the immune system in terms of cytokine production as well as on the total IgE levels.