I. Carla Lohman

TGF-β in human milk is associated with wheeze in infancy

Abstract Background Cytokines secreted in human milk might play important roles in newborn health and in the development of infant immune responses. We investigated the relationship of the concentration and dose of cytokines in human milk to infant wheeze at 1 year of age. Objective Our objective was to test whether the cytokines in milk could account for some of the apparent protective effect of breast-feeding against wheeze in the first year of life. Methods Data on breast-feeding and infant wheeze were collected prospectively from birth to 1 year from 243 mothers participating in the Infant Immune Study in Tucson, Arizona. Breast milk samples obtained at a mean age of 11 days postpartum were assayed by means of ELISA for concentrations of TGF-β1, IL-10, TNF-α, and the soluble form of CD14. The dose of each cytokine was assessed for a relationship with wheeze in bivariate and logistic regression analyses. Results Increasing duration of breast-feeding was significantly associated with a decreased prevalence of wheeze ( P = .039). There was wide variability in levels of each cytokine in milk, as well as variability between women in the amount of each cytokine produced. There was a significant inverse association between the dose of TGF-β1 received through milk with the percentage of wheeze ( P = .017), and the relationship was linear ( P = .006). None of the other cytokines showed a linear relationship with wheeze. In multivariate analyses the risk of wheeze was significantly decreased (odds ratio, 0.22; 95% CI 0.05-0.89; P = .034) with increasing TGF-β1 dose (long breast-feeding and medium-high TGF-β1 level compared with short breast-feeding and low TGF-β. Conclusion This analysis shows that the dose of TGF-β1 received from milk has a significant relationship with infant wheeze, which might account for at least some of the protective effect of breast-feeding against wheeze.

Th1/Th2 Patterns and Balance in Cytokine Production in the Parents and Infants of a Large Birth Cohort

Regulation of human immune cell cytokine production in vivo is not well understood due in part to limitations on imposing experimental conditions. We proposed that life-imposed conditions (pregnancy, birth, age, gender), combined with large sample size, repeat sampling, and family-based recruitment would serve to reveal peripheral blood cell-derived cytokine patterns reflective of in vivo regulation regarding Th1/Th2 balance and familial correlation. Mononuclear cells were obtained from 483 trios in the Tucson Infant Immune Study: from mothers pre- and postpartum, infants at birth and at 3 mo, and fathers. Con A/PMA-stimulated supernatants were assayed by ELISA for IFN-γ, IL-4, IL-13, IL-5, and IL-10 and allergen-stimulated supernatants for IFN-γ, IL-4, and IL-13. Mitogen-stimulated prepartum samples were not globally Th2 biased, differing from postpartum only by a modestly reduced IFN-γ:IL-5 ratio. Prepartum samples actually produced less IL-10 and IL-13 although more IL-5 than paternal samples. Newborns were also not globally Th2 biased, with mitogen stimulation producing ∼10-fold less IL-4, IL-5, and IFN-γ than adults but only 2- to 3-fold less IL-13 and IL-10. Despite these group differences, all cytokines showed marked positive intraindividual correlations (all p < 0.001). Allergen stimulation gave results consistent with a lack of global Th2 bias. Mitogen stimulation revealed parent-child and parent-parent correlations. Thus, rather than a global Th2 bias, cytokine production in pregnant mothers and newborns appears regulated so as to maintain a relative balance among the cytokines, with the nature of the balance differing in mothers and infants and with production influenced by familial factors that include shared environment.

Effects of Parental Smoking on Interferon γ Production in Children

OBJECTIVES. Environmental tobacco smoke is associated with several negative health outcomes in children, including an increased susceptibility to infections. One of the postulated mechanisms for these effects is the impairment of the immune system function and/or development. Yet, it remains unknown whether cumulative exposure to parental smoking is associated with altered immune responses in childhood and whether these effects are independent of in utero exposure to maternal smoking. In a population-based birth cohort, we sought to determine the relation of parental smoking, as assessed prospectively since pregnancy, to the childs interferon γ and interleukin 4 production at 11 years of age. PATIENTS AND METHODS. We used data on 512 children and their parents from the Tucson Childrens Respiratory Study cohort. Information on maternal and paternal smoking was collected prospectively by questionnaire, and pack-years for mother, father, and both parents combined were assessed prospectively between the prenatal period and year 11. At age 11 years, childrens interferon γ and interleukin 4 production from mitogen-stimulated peripheral blood mononuclear cells was measured. RESULTS. Children of parents who smoked between the prenatal period and year 11 were more likely to be in lower quartiles of interferon γ production than children of nonsmoking parents. In addition, maternal, paternal, and parental pack-years showed significant inverse dose-response relationships with interferon γ production in the child. These dose-response relationships with interferon γ remained significant for both paternal and parental pack-years among children of mothers who did not smoke during pregnancy, suggesting the existence of specific postnatal effects of environmental tobacco smoke exposure. In contrast, no significant effects of parental smoking were found on interleukin 4 production. CONCLUSIONS. Interferon γ responses of school-aged children are impacted by parental smoking.

The Differential Effect of Genetic Variation on Soluble CD14 Levels in Human Plasma and Milk

Problem:  The protein CD14 is a pattern recognition receptor for bacterial lipopolysaccharide (LPS). Whether genetic variation has the same influence on soluble CD14 (sCD14) levels in human plasma and milk remains to be determined.

Perinatal Tumor Necrosis Factor-α Production, Influenced by Maternal Pregnancy Weight Gain, Predicts Childhood Asthma

RATIONALE Innate immune responses marked by increases in tumor necrosis factor (TNF)-α have been associated with asthma but whether such alterations are evident before symptoms is not yet clear. OBJECTIVES To determine if prevalence of childhood asthma or asthma-related traits is predicted by perinatal innate immune status and if maternal factors related to pregnancy influence asthma prevalence and innate immune status. METHODS In the Tucson Infant Immune Study (a nonselected birth cohort), presence of eczema and wheezing in the childs first year and physician-diagnosed asthma through age 9 and asthma in the parents was obtained from parent-completed questionnaires. TNF-α, IL-6, IL-10, and IL-12 were measured in supernatants of LPS-stimulated peripheral blood mononuclear cells at birth and 3 months as was TNF-α in plasma. TNF-α single nucleotide polymorphisms were genotyped by Sequenom. Percent predicted FEV1/FVC was measured at age 9. Maternal weight gain during pregnancy and prepregnancy weight were ascertained from medical records. MEASUREMENTS AND MAIN RESULTS Infants with persistently elevated LPS-induced TNF-α at birth and 3 months were at increased risk for childhood asthma (odds ratio [OR], 4.1; confidence interval [CI], 1.9-8.8; n = 233; P = 0.0003) and had decreased FEV1/FVC ratios at age 9. Children with mothers in the top tertile for pregnancy weight gain had increased risk for asthma (OR, 3.4; CI, 1.7-6.9; n = 225; P = 0.001) and persistently elevated TNF-α in early life (OR, 2.9; CI, 1.4-8.2; n = 195; P = 0.013). These relations were independent of maternal asthma and rhinitis. CONCLUSIONS Persistently elevated LPS-induced TNF-α production early in life acts as a predictive biomarker for childhood asthma, and excess pregnancy weight gain in the mother seems to contribute to both.

Prenatal factors associated with the development of eczema in the first year of life.

Prenatal factors have been implicated in childhood eczema, but the relationship between maternal cytokine production during pregnancy and infant eczema is unknown. Non‐selected women in their third trimester were enrolled in the Tucson Infant Immune Study. Data from three sources were used to define MD‐eczema: parent‐completed illness questionnaires at age 2, 3, 4, 6 and 9 months regarding physician‐seen eczema, parent‐completed questionnaires at 12 months regarding physician‐diagnosed eczema, and medical record reviews. Blood samples were taken from mothers during their third trimester and from the umbilical cord at birth. Maternal peripheral blood mononuclear cells and cord blood mononuclear cells were stimulated with ConA/PMA, and supernatants were assayed for IFN‐γ and IL‐4, ‐5, ‐10, and ‐13. Of 364 children, 28% were seen by a physician for eczema by 1 yr of age. After adjustment for potential confounders using logistic regression, the odds for development of eczema in infancy were significantly higher when mothers had active eczema in pregnancy (OR, 2.46, CI 1.0–5.8, p < 0.042) and when mothers were in the highest tertile of serum IgE production (OR 2.28, CI 1.2–4.4, p < 0.013). Colds in the third trimester were associated with lower odds of eczema (OR 0.32, CI 0.16–0.63, p < 0.001). Our findings from this cohort study suggest that in utero factors, including maternal IgE, colds, and eczema, may influence the risk of infant eczema.

Epigenome-wide analysis links SMAD3 methylation at birth to asthma in children of asthmatic mothers.

Background The timing and mechanisms of asthma inception remain imprecisely defined. Although epigenetic mechanisms likely contribute to asthma pathogenesis, little is known about their role in asthma inception. Objective We sought to assess whether the trajectory to asthma begins already at birth and whether epigenetic mechanisms, specifically DNA methylation, contribute to asthma inception. Methods We used the Methylated CpG Island Recovery Assay chip to survey DNA methylation in cord blood mononuclear cells from 36 children (18 nonasthmatic and 18 asthmatic subjects by age 9 years) from the Infant Immune Study (IIS), an unselected birth cohort closely monitored for asthma for a decade. SMAD3 methylation in IIS (n = 60) and in 2 replication cohorts (the Manchester Asthma and Allergy Study [n = 30] and the Childhood Origins of Asthma Study [n = 28]) was analyzed by using bisulfite sequencing or Illumina 450K arrays. Cord blood mononuclear cell–derived IL‐1&bgr; levels were measured by means of ELISA. Results Neonatal immune cells harbored 589 differentially methylated regions that distinguished IIS children who did and did not have asthma by age 9 years. In all 3 cohorts methylation in SMAD3, the most connected node within the network of asthma‐associated, differentially methylated regions, was selectively increased in asthmatic children of asthmatic mothers and was associated with childhood asthma risk. Moreover, SMAD3 methylation in IIS neonates with maternal asthma was strongly and positively associated with neonatal production of IL‐1&bgr;, an innate inflammatory mediator. Conclusions The trajectory to childhood asthma begins at birth and involves epigenetic modifications in immunoregulatory and proinflammatory pathways. Maternal asthma influences epigenetic mechanisms that contribute to the inception of this trajectory. Graphical abstract Figure. No Caption available.

The role of histamine in the physiologic alterations of IgE anaphylaxis in the rabbit.

The respiratory and circulatory alterations induced by intravenous histamine in the pentobarbital anesthetized rabbit were examined and compared to those alterations associated with IgE anaphylaxis following antigen challenge. Histamine induced several graded alterations including an increase in total pulmonary resistance, a decrease in dynamic compliance, an increase in breathing frequency, a decrease in tidal volume, a rise in right ventricular systolic pressure and systemic hypotension. Qualitatively similar alterations occurred during the anaphylactic response, but a quantitative comparison of the two responses revealed that the respiratory alterations in systemic anaphylaxis corresponded to relatively low equivalent histamine doses, whereas the anaphylactic circulatory alterations exceeded the maximum response obtainable with histamine. Pretreatment with H1 antihistamine competitively blocked all of the ventilatory and lung mechanical changes induced by histamine, but it inhibited only the increase in pulmonary resistance induced by antigen. The right ventricular hypertension induced by histamine was also inhibited by H1 antihistamine but the antigen-induced change in this variable was not significantly attenuated. Inhibition of the histamine-induced systemic hypotension required pretreatment with both H1 and H2 histamine antagonists. Such pretreatment, however, did not attenuate the fall in systemic arterial pressure induced by antigen. H1 antihistamine pretreatment prevented histamine- but not antigen-induced lethality. We conclude that histamine is an important mediator of the increase in pulmonary resistance but is not the major mediator of the other physiological alterations of IgE systemic anaphylaxis in the rabbit.

Maternal cytokine profiles during pregnancy predict asthma in children of nonasthmatic mothers

&NA; Little is known about whether maternal immune status during pregnancy influences asthma development in the child. We measured cytokine production in supernatants from mitogen‐stimulated peripheral blood immune cells collected during and after pregnancy from the mothers of children enrolled in the Tucson Infant Immune Study, a nonselected birth cohort. Physician‐diagnosed active asthma in children through age 9 and a history of asthma in their mothers were assessed through questionnaires. Maternal production of each of the cytokines IL‐13, IL‐4, IL‐5, IFN‐&ggr;, IL‐10, and IL‐17 during pregnancy was unrelated to childhood asthma. However, IFN‐&ggr;/IL‐13 and IFN‐&ggr;/IL‐4 ratios during pregnancy were associated with a decreased risk of childhood asthma (n = 381; odds ratio [OR], 0.33; 95% confidence interval [CI], 0.17‐0.66; P = 0.002; and n = 368; OR, 0.36; 95% CI, 0.18‐0.71; P = 0.003, respectively). The inverse relations of these two ratios with childhood asthma were only evident in mothers without asthma (n = 309; OR, 0.18; 95% CI, 0.08‐0.42; P = 0.00007; and n = 299; OR, 0.17; 95% CI, 0.07‐0.39; P = 0.00003, respectively) and not in mothers with asthma (n = 72 and 69, respectively; P for interaction by maternal asthma = 0.036 and 0.002, respectively). Paternal cytokine ratios were unrelated to childhood asthma. Maternal cytokine ratios in mothers without asthma were unrelated to the childrens skin‐test reactivity, total IgE, physician‐confirmed allergic rhinitis at age 5, or eczema in infancy. To our knowledge, this study provides the first evidence that cytokine profiles in pregnant mothers without asthma relate to the risk for childhood asthma, but not allergy, and suggests a process of asthma development that begins in utero and is independent of allergy.

Predictors of neonatal production of IFN-γ and relation to later wheeze

Supernatant IFN-γ levels from mitogen-stimulated cord blood mononuclear cells were inversely associated with wheeze through age 2, but only among boys. This relation was not due to other factors associated with cord IFN-γ production.