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"July, 2001" / Addendum inserted in back. / Includes bibliographical references (leaves 250-284) / xxiii, 284 leaves : ill. (some col.), plates (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Surgery, 2001

[Truncated abstract] The dramatic increase in the expression of allergic diseases such as asthma and allergy over the last 20-30 years has highlighted the urgent need to identify causative factors. It was hypothesised that direct immune interactions between mother and fetus contribute to the cytokine milieu of pregnancy, thus influencing immune maturation after birth. Further it was speculated that the cytokine responses produced as a result of maternalfetal interactions are Th-2 skewed in women allergic disease, which programmes their offspring towards developing an allergic phenotype after birth. To test this hypothesis a cohort of 169 pregnant women were recruited at 20 weeks gestation and defined as allergic or non-allergic based on both clinical history and skin prick test sensitisation. These women and their infants were followed up throughout pregnancy (20 weeks, 30 weeks, 36 weeks gestation and 6 weeks post-partum) and up to 2.5 years of age. Mixed lymphocyte reactions (MLR) were used to measure maternal cytokine (IL-6, IL-10, IL-13 and IFN-) and lymphoproliferative responses to fetal alloantigens at each pregnancy time-point. Human leukocyte antigen (HLA) typing of mothers and infants were performed to assess the effect of HLA mismatch on maternal MLR responses to their fetus. After delivery, mononuclear cells (MNC) were isolated from cord blood (CB) and stimulated with allergens, mitogen and toll-like receptor (TLR) ligands. .... As IL-6 also participates in adaptive immunity by promoting Th-2 differentiation it is proposed that the production of IL-6 as a results of maternal encounters with paternal antigens during pregnancy, contribute to the Th-2 skewed responses observed universally in most infants at birth. Associations between maternal-fetal interaction and clinical outcomes in infancy: Although clinical signs of allergy in infancy were not the main outcome measure of this thesis, there were interesting, yet complex relationships between the production of these maternal cytokines towards the fetus and allergic disease at infant follow-ups. Increased maternal IFN-¿ to fetal alloantigen was associated with asthma at 2.5 years and a trend towards recurrent wheeze at 12 months. In contrast decreased maternal IL-13 production was associated with IgE mediated food allergy at 12 months. Adjusting for maternal allergy and other potential confounders including infant gender, method of delivery, HLA mismatch, and paternal allergy did not account for these relationships. Further follow-ups of these infants are required to determine if these relationship last in to early childhood. In conclusion, the findings of this thesis provides further support for the hypothesis that immune responses at birth are programmed prenatally, and that this programming has implications later in life. Importantly, the placenta is the immunologically active interface between mother and fetus during pregnancy. Therefore it is emphasised that there is a crucial need for future research to focus on early immune programming at the placental level before the aetiological pathways of immune mediated diseases can be fully elucidated.

[Truncated abstract] Fetal inflammatory response syndrome (FIRS) has only recently been recognised as an important cause of spontaneous preterm delivery (PTD). In addition, it has been associated with a number of other short-term and long-term adverse neonatal outcomes, including early onset neonatal sepsis, necrotising enterocolitis, periventricular leucomalacia, cerebral palsy, and bronchopulmonary dysplasia, although the causal mechanisms are unclear. The hallmark of FIRS is histologic chorioamnionitis (HCA). Mothers with HCA are often asymptomatic and it remains unclear whether elevated maternal inflammatory markers, such as C-reactive protein (CRP) and procalcitonin (PCT), are predictive of preterm birth. Furthermore neonatal inflammatory markers such as CRP, PCT, white cell count (WCC) and absolute neutrophil count (ANC), are commonly used in clinical practice to diagnose infection in the neonatal period. Although both intrauterine inflammation and FIRS may have effects on inflammatory markers for up to 10 days following delivery, the extent to which intrauterine infection and FIRS confound these diagnostic surrogates of neonatal infection is unknown. This work addressed the hypothesis that HCA is associated with inflammatory changes that may be detected in the: (a) maternal circulation at the time of delivery, (b) umbilical cord blood at delivery and (c) post-natal circulation within the first 48 hours of life. The primary aim of this study was to investigate the relationship between the presence of HCA and maternal inflammatory markers (serum CRP and PCT on the day of delivery) as well as neonatal inflammatory markers (haematological parameters, CRP and PCT up to 48 hours following delivery). ... Cord platelet counts were likely affected by platelet activation. For both intra-rater and inter-rater reproducibility, the corrected WCC, ANC and NRBC were shown to be reliable with an ICC of >0.90 for all comparisons. However, I:T ratio was poorly reproducible. HCA appears to be a minor inflammatory insult for the mother. In the majority of cases it is asymptomatic and results in minor increases in PCT and CRP levels on the day of delivery. Conversely HCA results in significant inflammatory changes in the newborn that can be seen in the cord blood. Sensitive markers of inflammation in the cord blood are significantly higher in affected infants (CRP and PCT), while less sensitive markers, such as WCC and ANC are not significantly different. This study has shown that fetal inflammation has sustained effects on CRP and haematological parameters in early neonatal life; CRP, WCC and ANC are significantly higher in newborns exposed to HCA, peaking 24 hours following delivery. These effects may confound the interpretation of common diagnostic tests for early onset neonatal sepsis. Conclusion: HCA results in mild elevations in CRP and PCT in the cord blood. Over the subsequent 24 hours CRP, WCC and ANC increase significantly in these neonates. Intrauterine exposure to HCA may influence surrogate diagnostic markers for early onset sepsis in newborn infants. Future research to investigate novel diagnostic markers, such as CD64 and soluble triggering receptor expressed on myeloid cells (TREM-1), or enhanced microbiological molecular diagnosis, will help distinguish true invasive infection from HCA-driven inflammation in the newborn infant.

[Truncated abstract] With the dramatic rise in asthma and allergic disease there is an urgent need to define the early life exposures which influence developing immune responses to increase the predisposition to allergic disease. While this is clearly multifactorial, this thesis addresses the effects of maternal smoking as a major adverse, yet avoidable exposure in early life. I hypothesised that the well-documented increased susceptibility to infection in infants of smokers could indicate underlying effects on innate Toll-like receptor (TLR) mediated microbial responses which could in turn contribute to early immune dysregulation and increased risk of allergic disease. In addition to providing the first defence against microbes, TLR-mediated pathways modulate subsequent specific immune response and are of growing interest in the potential inhibition of inappropriate allergic responses. My initial interest in the potential immune effects of smoking in pregnancy was based on preliminary retrospective analyses of a previous cohort (presented in Chapter 3) which suggested possible effects on T cell cytokine responses to mitogens and allergens. Based on this, I recruited a new prospective pregnancy cohort (n=122) of smokers (n=60) and non-smokers (n=62) (as outlined in Chapter 4) to confirm this and test my novel hypothesis that maternal smoking may be affecting important innate (TLR-mediated) immune pathways. … Thus, these findings could indicate that smoking increases the early susceptibility to infection thereby increasing subsequent IgA responses. This is supported by observations that key neonatal TLR responses are attenuated in children who go onto develop wheezy illnesses and lower respiratory tract infections. Together, the study findings suggest that in addition to effects on lung growth, maternal smoking may also influence aspects of neonatal innate immune function that are now believed to play a critical role in microbial-driven postnatal immune development, highlighting that other environmental interactions are also highly relevant to the v