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- Abelius, Martina, 1980-
(författare)
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Immunological interactions between mother and child during pregnancy in relation to the development of allergic diseases in the offspring
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Pregnancy and allergic disease have both been postulated as T-helper 2 (Th2) phenomena. Thus, the increased propensity of allergic mothers to mount Th2-responses might generate favourable effects on the maintenance of pregnancy, but might also be unfavorable, as fetal exposure to a strong Th2 environment could influence the immune development in the offspring to a Th2-like phenotype, favouring IgE production and possibly allergy development later in life. The influence of the intrauterine environment on the immunity and allergy development in the offspring needs to be further investigated.Aim: The aim of this thesis was to explore the Th1/Th2 balance in allergic and non-allergic women during pregnancy and its influence on the shaping of the Th1/Th2 profile in the neonate and the development of allergic diseases in the offspring.Material and methods: The study group included 20 women with and 36 women without allergic symptoms followed during pregnancy (gestational week 10-12, 15-16, 25, 35, 39) and 2 and 12 months postpartum, and their children followed from birth to 6 years of age. The circulating Th1-like chemokines CXCL9, CXCL10, CXCL11, Th2-like chemokines CCL17, CCL18 and CCL22, and the allergen-induced secretion of interleukin-4 (IL-4), IL-5, IL-10, IL-13, Interferon-γ (IFN-γ), CXCL10 and CCL17 were measured by Luminex and ELISA. The allergen-specific and total IgE levels were quantified using ImmunoCAP Technology. mRNA expression of Th1-, Th2-, Treg- and Th17-associated genes were measured by PCR arrays and real-time PCR.Results: We found that sensitised women with allergic symptoms had increased total IgE levels and birch- and cat-induced IL-5, IL-13 and CCL17 responses during pregnancy as compared with postpartum. The non-sensitised women without allergic symptoms had elevated cat-induced IL-5 and IL-13 responses and lower birch- and cat-induced IFN-γ during pregnancy, but similar IgE levels as compared with postpartum.Maternal total IgE levels during and after pregnancy correlated with cord blood (CB) IgE and CCL22 levels (regardless of maternal allergy status). Circulating CXCL11, CCL18 and CCL22 levels during pregnancy and postpartum correlated with the corresponding chemokine levels in the offspring at various time points during childhood. Maternal IL-5 expression in peripheral blood mononuclear cells (PBMC) was associated with neonatal Galectin-1, and placental p35 expression was negatively associated with neonatal Tbx21 expression. Increased mRNA expression of CCL22 in cord blood mononuclear cells (CBMC), and increased CCL17 and CCL22 levels in CB were observed in children later developing allergic symptoms and sensitisation as compared with children who did not. Development of allergic symptoms and sensitisation were associated with increased total IgE, CCL17, CCL18 and CCL22 levels during childhood.Conclusions: Maternal allergy was associated with a pronounced Th2 deviation during pregnancy, shown as increased total IgE levels and birch- and cat-induced IL-5, IL-13 and CCL17 responses during pregnancy, possibly exposing their fetuses to a particular strong Th2 environment during gestation.Correlations were shown between the maternal immunity during pregnancy and the offspring’s immunity at birth and later during childhood, indicating an interplay between the maternal and fetal immunity.Allergy development during the first 6 years of life was associated with a marked Th2 deviation at birth and a delayed down-regulation of this Th2-skewed immunity during childhood.
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| 2. |
- Edström, Måns, 1984-
(författare)
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Regulation of immunity in Multiple Sclerosis : CD4+ T cells and the influence of natalizumab
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Multiple sclerosis (MS) is an autoimmune disease targeting the central nervous system (CNS) and the most common neurological cause of disability in young adults. In most cases, the disease course is characterised by the cycling of relapses and remissions, so called relapsing-remitting MS (RR-MS). Although extensively studied, the underlying mechanisms are not fully elucidated, yet CD4+ T cells have been shown to be of importance in disease pathology. A range of treatments are available; the most effective to date being natalizumab, a monoclonal antibody directed against the adhesion molecule VLA-4 on the lymphocyte surface, thereby preventing entry into the CNS.The aim of this thesis was to assess the nature of lymphocyte populations in MS. This was achieved by studying CD4+ T helper cells (TH) and regulatory T cells (TREG) in peripheral blood. In addition, the influence of natalizumab was also investigated, both regarding the effect of the drug on the composition of the peripheral lymphocyte compartment as well as its effects on CD4+ T cells in vitro.We showed an imbalance in the mRNA expression of CD4+ T helper cell lineage specific transcription factors in peripheral blood. While TH1 and TH17 associated TBX21 and RORC expression was comparable in MS and healthy individuals, the TH2 and TREG associated GATA3 and FOXP3 expression was decreased in RR-MS. Given the reciprocally inhibitory nature of TH subsets, this might imply not only diminished function of TH2 and TREG cells but also a permissive state of harmful TH1 and TH17 cells. The size of the peripheral TREG population was unaltered in RR-MS. When analysed in detail, activated and resting TREG were distinguished, showing clear differences in FOXP3 and CD39 expression. Furthermore, when investigating these subpopulations functionally, the ability of activated TREG to suppress proliferation of responder T cells was found to be decreased in RR-MS patients compared to controls. To further investigate this defect, the global gene expression of TREG was compared between patients and controls. Gene set enrichment analysis revealed an enrichment (over-expression) of chemokine receptor signalling genes in RR-MS TREG, possibly suggesting a role for chemokines in TREG function.A sizable effect of natalizumab treatment was seen in the composition of peripheral lymphocyte populations after one year of treatment. While the number of lymphocytes increased over all, the largest increase was seen in the NK and B cell compartments. Furthermore, T cells from patients with MS displayed decreased responsiveness towards antigens and mitogens in vitro. Natalizumab treatment was able to normalise the responsiveness in blood, an effect not solely dependent on the increased number of cells.The importance of CD4+ T cells in human disease, including MS, was shown by a systems biology approach; using GWAS data, genes associated with CD4+ T cell differentiation were enriched for many, not only immunerelated, diseases. Furthermore, global CD4+ T cell gene expression (by microarray) could discriminate between patients and controls. Lastly, using in vitro treated CD4+ T cells, we could show that natalizumab perturbated gene expression differently in patients responding to the drug compared to those not responding.In conclusion, our results demonstrate an imbalance of peripheral CD4+ T cells in MS, along with a functional deficiency in the case of TREG. Taken together, these aberrations might result in differentiation and activation of harmful TH1 and TH17 cells, resulting in CNS tissue damage. The importance of CD4+ T cells was further demonstrated by the finding that genes associated with CD4+ T cell differentiation constitute a pleiotropic module common to a number of diseases. Investigation of natalizumab revealed drastic changes in the peripheral lymphocyte compartment caused by treatment. It also appears as treatment might influence the responsiveness of peripheral T cells to antigens. In addition, by using CD4+ T cell transcriptomics after in vitro drug exposure, prediction of treatment outcome may be possible.
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| 3. |
- Persson, Marie
(författare)
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Immune regulation during pregnancy in relation to allergy and in women undergoing in vitro fertilization
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During pregnancy, the fetus expresses both maternal and paternal antigens. To the mother, the paternal antigens are foreign, providing her immune system with an interesting challenge. The fact that the fetus is not normally attacked and rejected implies that mechanisms of tolerance must exist. Pregnancy has long been considered to cause a redirection of the maternal immune responses towards a less aggressive type. Allergic disease has also been associated with that same redirection of immune responses, suggesting that this deviation may be more pronounced in allergic women during pregnancy. Several observations support the concept of a role of the immune system in the etiology of unexplained infertility, associating a redirection of the immune responses towards a more aggressive type with pregnancy loss and pregnancy failure.The aim of this thesis was to investigate the immune responses during pregnancy in allergic and non-allergic women, and in infertile women undergoing IVF treatment. We hypothesized that allergic women would have a more pronounced Th2-deviation than non-allergic women towards paternal antigens during pregnancy and that an unsuccessful outcome of IVF treatment would be associated with aberrations in circulating leukocyte populations and a paternal antigen-specific Th1 and Th17 bias.An increased number of both spontaneous and paternal antigen-induced Th2-like cytokine-secreting cells in peripheral blood was associated with pregnancy in 54 women with pregnancies defined as normal. The allergic pregnant women did not have a more pronounced Th2-deviation than the non-allergic women, as measured by numbers of cytokine-secreting cells. However, when analyzing cytokine levels in cell supernatants, we did observe lower Th1 responses towards paternal antigens in the allergic compared with non-allergic women. Additionally, allergy was associated with a reduced capacity to induce anti-inflammatory IL-10 responses towards paternal antigens.In 25 infertile women undergoing IVF, the peak levels of the majority of paternal antigen-induced cytokines and leukocyte populations investigated coincided with the maximal levels of gonadotropins administered during IVF treatment, suggesting that controlled ovarian hyper-stimulation has a general stimulatory effect on the immune system and that it may be regarded as an inflammatory state. During the treatment, no differences were found regarding cytokine responses to paternal antigens in peripheral blood or the numbers or proportions of circulating leukocyte populations between women with a successful or unsuccessful outcome of IVF. We did see higher numbers of Th2-associated cytokine secreting cells and a lower proportion of lymphocytes in the pregnant compared with the non-pregnant women four weeks after embryo transfer, however, in line with previous findings of immune modulation during pregnancy.In conclusion, normal pregnancy seems to be characterized by a less aggressive type of immune responses, possibly more pronounced in allergic women. This may be of importance for the in utero influences on childhood allergy development. An unsuccessful outcome of IVF does not appear to be associated with a more aggressive type of immune responses towards paternal antigens or aberrations in circulating leukocyte populations, although this should be confirmed in a larger study. The results in this thesis also indicate that the hormonal therapy during IVF treatment has a stimulatory effect on the immune system, generating an inflammatory state.
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