Petra Amoudruz

Maternal country of origin, breast milk characteristics and potential influences on immunity in offspring

Breast milk contains pro‐ and anti‐inflammatory cytokines and chemokines with potential to influence immunological maturation in the child. We have shown previously that country of birth is associated with the cytokine/chemokine profile of breast milk. In this study we have investigated how these differences in breast milk affect the cellular response of cord blood mononuclear cells (CBMCs) and intestinal epithelial cells (IECs, cell line HT‐29) to microbial challenge. Ninety‐five women were included: 30 from Mali in West Africa, 32 Swedish immigrants and 33 native Swedish women. CBMCs or IECs were stimulated in vitro with breast milk, alone or in combination with lipopolysaccharide (LPS) or peptidoglycan (PGN). Breast milk in general abrogated the LPS‐induced down‐regulation of surface CD14 and Toll‐like receptor (TLR)‐4 expression on CB monocytes, while inhibiting the PGN‐induced TLR‐2 up‐regulation. However, breast milk from immigrant women together with LPS induced a lower CBMC release of interleukin (IL)‐6 (P = 0·034) and CXCL‐8/IL‐8 (P = 0·037) compared with breast milk from Swedish women, while breast milk from Swedish women and Mali women tended to increase the response. The same pattern of CXCL‐8/IL‐8 release could be seen after stimulation of IECs (HT‐29). The lower CBMC and IEC (HT‐29) responses to microbial compounds by breast milk from immigrant women could be explained by the fact that breast milk from the immigrant group showed a divergent pro‐ and anti‐inflammatory content for CXCL‐8/IL‐8, transforming growth factor‐β1 and soluble CD14, compared to the other two groups of women. This may have implications for maturation of their childrens immune responses.

Pregnancy, but not the allergic status, influences spontaneous and induced interleukin-1β (il-1β), 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‐1β (IL‐1β), 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‐1β, 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.

Impaired Toll-like receptor 2 signalling in monocytes from 5-year-old allergic children

The relative composition of the two major monocytic subsets CD14+CD16− and CD14+CD16+ is altered in some allergic diseases. These two subsets display different patterns of Toll‐like receptor levels, which could have implications for activation of innate immunity leading to reduced immunoglobulin E‐specific adaptive immune responses. This study aimed to investigate if allergic status at the age of 5 years is linked to differences in monocytic subset composition and their Toll‐like receptor levels, and further, to determine if Toll‐like receptor regulation and cytokine production upon microbial stimuli is influenced by the allergic phenotype. Peripheral blood mononuclear cells from 5‐year‐old allergic and non‐allergic children were stimulated in vitro with lipopolysaccharide and peptidoglycan. Cells were analysed with flow cytometry for expression of CD14, Toll‐like receptors 2 and 4 and p38‐mitogen‐activated protein kinase (MAPK). The release of cytokines and chemokines [tumour necrosis factor, interleukin (IL)‐1β, IL‐6, IL‐8, IL‐10, IL‐12p70] into culture supernatants was measured with cytometric bead array. For unstimulated cells there were no differences in frequency of the monocytic subsets or their Toll‐like receptor levels between allergic and non‐allergic children. However, monocytes from allergic children had a significantly lower up‐regulation of Toll‐like receptor 2 upon peptidoglycan stimulation. Further, monocytes from allergic children had a higher spontaneous production of IL‐6, but there were no differences between the two groups regarding p38‐MAPK activity or cytokine and chemokine production upon stimulation. The allergic subjects in this study have a monocytic population that seems to display a hyporesponsive state as implicated by impaired regulation of Toll‐like receptor 2 upon peptidoglycan stimulation.

Maternal country of birth and previous pregnancies are associated with breast milk characteristics

Populations in high infectious exposure countries are at low risk of some immune‐mediated diseases such as Crohn’s disease and allergy. This low risk is maintained upon immigration to an industrialized country, but the offspring of such immigrants have a higher immune‐mediated disease risk than the indigenous population. We hypothesize that early life exposures in a developing country shape the maternal immune system, which could have implications for the offspring born in a developed country with a low infectious load. The aim of this study was to investigate if exposures in childhood (indicated by country of origin) and subsequent exposures influence immunologic characteristics relevant to stimulation of offspring. Breast milk components among 64 mothers resident in Sweden, 32 of whom immigrated from a developing country, were examined using the ELISA and Cytometric Bead Array methods. Immigrants from a developing country had statistically significantly higher levels of breast milk interleukin‐6 (IL‐6), IL‐8 and transforming growth factor‐β1. A larger number of previous pregnancies were associated with down‐regulation of several substances, statistically significant for soluble CD14 and IL‐8. The results suggest that maternal country of birth may influence adult immune characteristics, potentially relevant to disease risk in offspring. Such a mechanism may explain the higher immune‐mediated disease risk among children of migrants from a developing to developed country. Older siblings may influence disease risk through the action of previous pregnancies on maternal immune characteristics.

Maternal allergy influences p38-mitogen-activated protein kinase activity upon microbial challenge in CD14+ monocytes from 2-year-old children

Background The development of allergic diseases is dependent on genetic and environmental factors. It has been shown previously that cord blood mononuclear cells (CBMCs) from infants with parental allergy have altered cytokine profiles upon bacterial encounter; it might be possible that such impairment persists during the early years of childhood.

Allergic women have reduced sHLA-G plasma levels at delivery.

Problem  HLA‐G antigen maintains a tolerogenic condition at the foeto‐maternal interface, counteracts inflammation in autoimmune diseases and soluble HLA‐G (sHLA‐G) levels decrease in allergic‐asthmatics. Taking into consideration these findings, we analyzed if sHLA‐G and interleukin‐10 (IL‐10) could be influenced by pregnancy and labour in allergic and non‐allergic women.

ORIGINAL ARTICLE: Allergic Women have Reduced sHLA‐G Plasma Levels at Delivery

Problem  HLA‐G antigen maintains a tolerogenic condition at the foeto‐maternal interface, counteracts inflammation in autoimmune diseases and soluble HLA‐G (sHLA‐G) levels decrease in allergic‐asthmatics. Taking into consideration these findings, we analyzed if sHLA‐G and interleukin‐10 (IL‐10) could be influenced by pregnancy and labour in allergic and non‐allergic women.

ORIGINAL ARTICLE: Allergic Women have Reduced sHLA-G Plasma Levels at Delivery: PLASMA SOLUBLE HLA-G DURING AND AFTER PREGNANCY

Problem  HLA‐G antigen maintains a tolerogenic condition at the foeto‐maternal interface, counteracts inflammation in autoimmune diseases and soluble HLA‐G (sHLA‐G) levels decrease in allergic‐asthmatics. Taking into consideration these findings, we analyzed if sHLA‐G and interleukin‐10 (IL‐10) could be influenced by pregnancy and labour in allergic and non‐allergic women.