Birth season and environmental influences on blood leucocyte and lymphocyte subpopulations in rural Gambian infants

Effect of organophosphorus pesticide exposure on the immune cell phenotypes among farm women and their children

Epidemiological studies suggest suppression of the lymphocytes function through cholinergic stimulation due to organophosphorus pesticide exposure. The study aimed to assess the alteration in the levels of immune cell phenotypes among farm women (FW) and farm children (FC) who were occupationally exposed to pesticides and age/gender-matched control subjects belonging to Rangareddy district (Telangana, India). A total of 129 FW, 129 FC and 268 age/gender-matched controls were recruited. Blood samples were collected from the selected subjects to estimate the levels of nine organophosphorus pesticide residues and CD (CD3+, CD4+, CD8+, CD16+ and CD19+) cell markers using LC-MS/MS and flow cytometry, respectively. Independent t-test analysis was conducted to compare the immune cell phenotypes between exposed and control groups. Spearman's rank correlation test was further carried out to identify any possible correlation between the pesticide residues and CD markers. The mean percentage for CD4+, CD8+ and CD16+ was found to be significantly low, while for CD19 + itwas significantly high in the FW as compared to the CW group (p < 0.01). Further, the residues of chlorpyrifos and monocrotophos among FW were found to be significantly correlating with the mean percentages of CD19+ and CD8+ markers, respectively. The cell marker subsets of CD4+ and CD8+ were significantly low in FC children 9-12 years and 13-15 years age groups, respectively (p < 0.05). Also, these levels were significantly correlating with the residues of malathion and monocrotophos. The present study could indicate an alteration in the lymphocytes' subpopulations, which may thereby infer the toxicity in the first phase assessment of immunotoxicity. Therefore, further studies may be conducted to understand the suspected pesticides' mechanism along with various other factors in causing immune suppression coupled with nutritional and other related disorders.

Seasonal modulation of antibody response to diphtheria-tetanus-pertussis vaccination in infants: a cohort study in rural Gambia

BACKGROUND

In rural Gambia, rates of malnutrition and infection are higher during the annual rainy/'hungry' season (June-October) in comparison to the dry/'harvest' season (November-May). The effects of this seasonal pattern on an infant's immune development and their capacity to respond to childhood vaccinations remain unclear. The aim of the current analysis was to determine whether antibody responses to diphtheria-tetanus-pertussis (DTP) vaccinations in infants differ between seasons.

METHODS

Infants received the DTP vaccine at 8, 12 and 16 weeks of age and antibody titres were measured in blood samples collected at 12 (n = 710) and 24 (n = 662) weeks of age. Mean DTP antibody titres, adjusted for maternal and infant confounders, were compared by t-tests and the effect sizes of the mean differences were calculated between seasons at mid-gestation (20 weeks gestation) and first vaccination (8 weeks of infant age).

RESULTS

A smaller number of infants received their first vaccination during the rainy/hungry season months compared to the dry/harvest season (n = 224 vs. n = 486). At 12 weeks, infants vaccinated during the rainy/hungry season had lower weight-for-length Z-scores (p = 0.01) and were more likely to be anaemic (p < 0.001). Their mothers, however, were pregnant mostly during the dry/harvest season, had higher weight gain (p < 0.001) and were less likely to be anaemic during pregnancy (p < 0.001). At 12 weeks, infants vaccinated during the rainy/hungry season had significantly higher mean diphtheria, tetanus and pertussis antibody titres; by 62.3, 16.9 and 19.7%, respectively (all, p < 0.001). However, at 24 weeks, they had lower mean anti-diphtheria titres (by 20.6%, p < 0.001) compared with infants vaccinated during the dry/harvest season, and no differences were observed in mean tetanus and pertussis antibody titres by vaccination season.

CONCLUSIONS

Infant antibody response to the primary dose of the DTP vaccine was influenced by both season of pregnancy and infancy, although effects were diminished following three doses. Environmental exposures, including nutrition, to both the mother and infant are hypothesised as likely drivers of these seasonal effects.

Prenatal and Perinatal Environmental Influences Shaping the Neonatal Immune System: A Focus on Asthma and Allergy Origins

It is suggested that programming of the immune system starts before birth and is shaped by environmental influences acting during critical windows of susceptibility for human development. Prenatal and perinatal exposure to physiological, biological, physical, or chemical factors can trigger permanent, irreversible changes to the developing immune system, which may be reflected in cord blood of neonates. The aim of this narrative review is to summarize the evidence on the role of the prenatal and perinatal environment, including season of birth, mode of delivery, exposure to common allergens, a farming environment, pet ownership, and exposure to tobacco smoking and pollutants, in shaping the immune cell populations and cytokines at birth in humans. We also discuss how reported disruptions in the immune system at birth might contribute to the development of asthma and related allergic manifestations later in life.

Naïve regulatory T cells in infancy: Associations with perinatal factors and development of food allergy

BACKGROUND

In previous studies, deficits in regulatory T-cell (Treg) number and function at birth have been linked with subsequent allergic disease. However, longitudinal studies that account for relevant perinatal factors are required. The aim of this study was to investigate the relationship between perinatal factors, naïve Treg (nTreg) over the first postnatal year and development of food allergy.

METHODS

In a birth cohort (n = 1074), the proportion of nTreg in the CD4⁺ T-cell compartment was measured by flow cytometry at birth (n = 463), 6 (n = 600) and 12 (n = 675) months. IgE-mediated food allergy was determined by food challenge at 1 year. Associations between perinatal factors (gestation, labour, sex, birth size), nTreg at each time point and food allergy at 1 year were examined by linear regression.

RESULTS

A higher proportion of nTreg at birth, larger birth size and male sex was each associated with higher nTreg in infancy. Exposure to labour, as compared to delivery by prelabour Caesarean section, was associated with a transient decrease nTreg. Infants that developed food allergy had decreased nTreg at birth, and the labour-associated decrease in nTreg at birth was more evident among infants with subsequent food allergy. Mode of birth was not associated with risk of food allergy, and there was no evidence that nTreg at either 6 or 12 months were related to food allergy.

CONCLUSION

The proportion of nTreg at birth is a major determinant of the proportion present throughout infancy, highlighting the importance of prenatal immune development. Exposure to the inflammatory stimulus of labour appears to reveal differences in immune function among infants at risk of food allergy.

Thymic size is increased by infancy, but not pregnancy, nutritional supplementation in rural Gambian children: a randomized clinical trial

BACKGROUND

Thymic size in early infancy predicts subsequent survival in low-income settings. The human thymus develops from early gestation, is most active in early life and is highly sensitive to malnutrition. Our objective was to test whether thymic size in infancy could be increased by maternal and/or infant nutritional supplementation.

METHODS

The Early Nutrition and Immune Development (ENID) Trial was a randomized 2 × 2 × 2 factorial, partially blinded trial of nutritional supplementation conducted in rural Gambia, West Africa. Pregnant women (N = 875) were randomized to four intervention groups (iron-folate (standard care), multiple micronutrients, protein energy or protein energy + multiple micronutrients at 'booking' (mean gestational age at enrolment = 13.6 weeks, range 8-20 weeks) until delivery. The iron-folate and multiple micronutrient arms were administered in tablet form and the protein energy arms as a lipid-based nutritional supplement. All intervention arms contained 60 mg iron and 400 μg folic acid per daily dose. From 24 to 52 weeks of age, infants from all groups were randomized to receive a daily lipid-based nutritional supplement, with or without additional micronutrients. Thymic size was assessed by ultrasonography at 1, 8, 24 and 52 weeks of infant age, and a volume-related thymic index calculated. Detailed data on infant growth, feeding status and morbidity were collected.

RESULTS

A total of 724 (82.7%) mother-infant pairs completed the trial to infant age 52 weeks. Thymic size in infancy was not significantly associated with maternal supplement group at any post-natal time point. Infants who received the daily LNS with additional micronutrients had a significantly larger thymic index at 52 weeks of age (equivalent to an 8.0% increase in thymic index [95% CI 2.89, 13.4], P = 0.002). No interaction was observed between maternal and infant supplement groups.

CONCLUSIONS

A micronutrient-fortified lipid-based supplement given in the latter half of infancy increased thymic size, a key mediator of immune function. Improving the micronutrient status of infants from populations with marginal micronutrient status may improve immune development and survival.

TRIAL REGISTRATION

ISRCTN registry (controlled-trials.com) Identifier: ISRCTN49285450.

Differences in multiple immune parameters between Indian and U.S. infants

To compare immune phenotypes across two geographic and ethnic communities, we examined umbilical cord blood by flow cytometry and Luminex in parallel cohorts of 53 newborns from New Delhi, India, and 46 newborns from Stanford, California. We found that frequencies of a B cell subset suggested to be B-1-like, and serum IgM concentration were both significantly higher in the Stanford cohort, independent of differences in maternal age. While serum IgA levels were also significantly higher in the Stanford cohort, IgG1, IgG2, and IgG4 were significantly higher in the New Delhi samples. We found that neutrophils, plasmacytoid dendritic cells, CD8+ T cells, and total T cells were higher in the U.S. cohort, while dendritic cells, patrolling monocytes (CD14dimCD16+), natural killer cells, CD4+ T cells, and naïve B cells were higher in the India cohort. Within the India cohort, we also identified cell types whose frequency was positively or negatively predictive of occurrence of infection(s) in the first six months of life. Monocytes, total T cells, and memory CD4+ T cells were most prominent in having an inverse relationship with infection. We suggest that these data provide impetus for follow-up studies linking phenotypic differences to environmental versus genetic factors, and to infection outcomes.

Seasonal and sex-specific variations in haematological parameters in 4 to 5.5-month-old infants in Guinea-Bissau, West Africa

Objective

This study investigated seasonal and sex-specific variations in the haematological parameters and established reference ranges for these parameters in healthy 4 to 5.5-month-old infants in Guinea-Bissau.

Methods

Within a randomised trial of early measles vaccination, over a period of 13 months blood samples were collected from infants aged 4 to 5.5 months. Haematological parameters were determined by an automated cell counter and compared in linear regression models providing geometric mean ratios (GMR).

Results

Blood samples from 501 infants (n=248 boys, 49.5%) were obtained, and 285 (56.9%) were collected in the rainy season. Median age was 4.7 months (range 3.7 to 7.2 months). Eosinophil and platelet counts were lower in the dry season (December to May) than in the rainy season (GMR 0.79 [95% CI 0.68–0.92]) and 0.93 [0.87–1.00], respectively). The calculated reference ranges were wider and generally higher than those from a US population of comparable age, but neutrophil levels were notably lower in Guinea-Bissau.

Conclusions

The study indicated that eosinophil and platelet counts of infants were subject to seasonal variations. The reference ranges for haematological values were comparable to other African populations and corroborated that neutropenia regularly occurs in African infants.

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

Maternal nutritional status during pregnancy and infant immune response to routine childhood vaccinations

To systematically review the association between maternal nutritional status in pregnancy and infant immune response to childhood vaccines. We reviewed literature on maternal nutrition during pregnancy, fetal immune system and vaccines and possible relationships. Thereafter, we undertook a systematic review of the literature of maternal nutritional status and infant vaccine response, extracted relevant information, assessed quality of the nine papers identified and present findings in a narrative format. From limited evidence of average quality, intrauterine nutrition deficiency could lead to functional deficit in the infant's immune function; child vaccine response may thus be negatively affected by maternal malnutrition. Response to childhood vaccination may be associated with fetal and early life environment; evaluation of programs should take this into account.

Effect of prenatal antioxidant intake on infants' respiratory infection is modified by a CD14 polymorphism

BACKGROUND

Prenatal maternal diet may influence disease susceptibility in offspring with specific genetic backgrounds. We hypothesized that interactions between prenatal antioxidant intake and polymorphisms in immunity genes influence respiratory tract infection (RTI) susceptibility in infants at 12 months of age.

METHODS

This study included 550 infants. In the Cohort for Childhood Origin of Asthma and Allergic Diseases (COCOA) birth cohort study, prenatal maternal diet was assessed by administering a food frequency questionnaire. Infants' cord blood was genotyped for CD14 (rs2569190), TLR4 (rs1927911), and GSDMB (rs4794820) polymorphisms by the TaqMan method.

RESULTS

Higher prenatal intake of total fruit and vegetables (FV) was associated with the decreased risk of RTI in offspring (P-trend=0.0430). In children with TT genotype at rs2569190, a higher prenatal intake of vitamins A and C, fruits, and total FV decreased RTI risk (P-trend <0.05), while in infants with TC+CC genotype, a higher prenatal intake of fruit increased RTI risk (P-trend <0.05). When analyzing the 3 genotypes, children with TT genotype at rs2569190 were more protected against RTIs compared with those with CC genotype with respect to vitamin C and fruits [odds ratio (OR)=5.04 and OR=10.30, respectively]. In children with CC genotype at rs1927911, RTI risk showed a dose-response association with a higher prenatal intake of vitamin C (P for interaction<0.05). A higher prenatal intake of fruits and total FV reduced RTI risk in infants with GA+AA genotype of rs4794820 (P for interaction<0.05).

CONCLUSIONS

Prenatal antioxidant intake may reduce RTI risk in infants and this relationship may be modified by CD14, TLR4, and GSDMB polymorphisms.

The large contribution of twins to neonatal and post-neonatal mortality in The Gambia, a 5-year prospective study

BACKGROUND

A high twinning rate and an increased risk of mortality among twins contribute to the high burden of infant mortality in Africa. This study examined the contribution of twins to neonatal and post-neonatal mortality in The Gambia, and evaluated factors that contribute to the excess mortality among twins.

METHODS

We analysed data from the Basse Health and Demographic Surveillance System (BHDSS) collected from January 2009 to December 2013. Demographic and epidemiological variables were assessed for their association with mortality in different age groups.

RESULTS

We included 32,436 singletons and 1083 twins in the analysis (twining rate 16.7/1000 deliveries). Twins represented 11.8 % of all neonatal deaths and 7.8 % of post-neonatal deaths. Mortality among twins was higher than in singletons [adjusted odds ratio (AOR) 4.33 (95 % CI: 3.09, 6.06) in the neonatal period and 2.61 (95 % CI: 1.85, 3.68) in the post-neonatal period]. Post-neonatal mortality among twins increased in girls (P for interaction = 0.064), being born during the dry season (P for interaction = 0.030) and lacking access to clean water (P for interaction = 0.042).

CONCLUSION

Mortality among twins makes a significant contribution to the high burden of neonatal and post-neonatal mortality in The Gambia and preventive interventions targeting twins should be prioritized.

Active Tuberculosis in HIV-Exposed Tanzanian Children up to 2 years of Age: Early-Life Nutrition, Multivitamin Supplementation and Other Potential Risk Factors

BACKGROUND

Over half a million children worldwide develop active tuberculosis (TB) each year. Early-life nutritional exposures have rarely been examined in relation to pediatric TB among HIV-exposed children. We therefore investigated independent associations of early-life nutritional exposures with active TB among HIV-exposed children up to 2 years of age.

METHODS

Participants were children from a randomized controlled multivitamin supplementation trial conducted in Dar es Salaam, Tanzania, from August 2004 to May 2008, who received daily multivitamin supplements or placebo for 24 months.

RESULTS

Lower mean corpuscular volumes [relative risks (RR): 0.48, 95% confidence interval (CI): 0.27, 0.87] and higher birth weights (RR: 0.61, 95% CI: 0.37, 0.99) were protective against active TB, whereas multivitamin supplementation was not associated with TB risk (RR: 0.87, 95% CI: 0.65, 1.16).

CONCLUSIONS

Knowledge of nutrition-related risk and protective factors for TB in HIV-exposed children could enhance preventive and case-finding activities in this population, contributing to efforts to reduce the global TB burden.

Early life nutritional programming of health and disease in The Gambia

Exposures during the early life (periconceptional, prenatal and early postnatal) period are increasingly recognized as playing an important role in the aetiology of chronic non-communicable diseases (NCD), including coronary heart disease, stroke, hypertension, Type 2 diabetes and osteoporosis. The 'Developmental Origins of Health and Disease' (DOHaD) hypothesis states that these disorders originate through unbalanced nutrition early in life and risk is highest when there is a 'mismatch' between the early- and later-life environments. Thus, the DOHaD hypothesis would predict highest risk in countries where an excess of infants are born with low birth weight and where there is a rapid transition to nutritional adequacy or excess in adulthood. Here, I will review data from work conducted in rural Gambia, West Africa. Using demographic data dating back to the 1940s, the follow-up of randomized controlled trials of nutritional supplementation in pregnancy and the 'experiment of nature' that seasonality in this region provides, we have investigated the DOHaD hypothesis in a population with high rates of maternal and infant under-nutrition, a high burden from infectious disease, and an emerging risk of NCDs.

The role of environmental factors in modulating immune responses in early life

The concept of immunological memory stipulates that past exposures shape present immune function. These exposures include not only specific antigens impacting adaptive immune memory but also conserved pathogen or danger associated molecular patterns that mold innate immune responses for prolonged periods of time. It should thus not come as a surprise that there is a vast range of external or environmental factors that impact immunity. The importance of environmental factors modulating immunity is most readily recognized in early life, a period of rapidly changing environments. We here summarize available data on the role of environment shaping immune development and from it derive an overarching hypothesis relating the underlying molecular mechanisms and evolutionary principles involved.

Pre-birth world and the development of the immune system: mum's diet affects our adult health: new insight on how the diet during pregnancy permanently influences offspring health and immune fitness

Secondary lymphoid organs form in utero through an inherited and well-established developmental program. However, maternal non-heritable features can have a major impact on the gene expression of the embryo, hence influencing the future health of the offspring. Recently, maternal retinoids were shown to regulate the formation of immune structures, shedding light on the role of maternal nutrition in the genetic signature of emergent immune cells. Here we highlight evidence showing how the maternal diet influences the establishment of the immune system, and we also discuss how unbalanced maternal diets may set the response to infection and vaccination in the progeny.

Thymus development and infant and child mortality in rural Bangladesh

BACKGROUND

Data from West Africa indicate that a small thymus at birth and at 6 months of age is a strong and independent risk factor for infection-related mortality up to 24 and 36 months of age, respectively. We investigated the association between thymus size (thymic index, TI) in infancy and subsequent infant and child survival in a contemporary South Asian population.

METHODS

The study focused on the follow-up of a randomized trial of prenatal nutritional interventions in rural Bangladesh (ISRCTN16581394), with TI measured longitudinally in infancy (at birth and weeks 8, 24 and 52 of age) and accurate recording of mortality up to 5 years of age.

RESULTS

A total of 3267 infants were born into the Maternal and Infant Nutrition Interventions, Matlab study; data on TI were available for 1168 infants at birth, increasing to 2094 infants by 52 weeks of age. TI in relation to body size was largest at birth, decreasing through infancy. For infants with at least one measure of TI available, there were a total of 99 deaths up to the age of 5 years. No association was observed between TI and subsequent mortality when TI was measured at birth. However, an association with mortality was observed with TI at 8 weeks of age [odds ratio (OR) for change in mortality risk associated with 1 standard deviation change in TI: all deaths: OR = 0.64, 95% confidence interval (CI) 0.41, 0.98; P = 0.038; and infection-related deaths only: OR = 0.32, 95% CI 0.14, 0.74; P = 0.008]. For TI when measured at 24 and 52 weeks of age, the numbers of infection-related deaths were too few (3 and 1, respectively) for any meaningful association to be observed.

CONCLUSION

These results confirm that thymus size in early infancy predicts subsequent survival in a lower mortality setting than West Africa. The absence of an effect at birth and its appearance at 8 weeks of age suggests early postnatal influences such as breast milk trophic factors.

Effects of malnutrition on children's immunity to bacterial antigens in Northern Senegal

To evaluate immunity to vaccine-preventable diseases according to nutritional status, a longitudinal study was conducted in Senegalese children ages 1-9 years old. A linear regression analysis predicted that weight for age was positively associated with immunoglobulin G (IgG) response to tetanus toxoid in children born during the rainy season or at the beginning of the dry season. A relationship between village, time of visits, and levels of antibodies to tetanus showed that environmental factors played a role in modulating humoral immunity to tetanus vaccine over time. Moreover, a whole-blood stimulation assay highlighted that the production of interferon-γ (IFN-γ) in response to tetanus toxoid was compromised in stunted children. However, the absence of cytokine modulation in response to Mycobacterium tuberculosis-purified protein derivatives and phytohemagglutinin suggests that the overall ability to produce IFN-γ was preserved in stunted children. Therefore, these results show that nutritional status can specifically alter the efficacy of long-lasting immunity to tetanus.

Intergenerational effects of maternal birth season on offspring size in rural Gambia

Environmental conditions experienced in early life can influence an individual's growth and long-term health, and potentially also that of their offspring. However, such developmental effects on intergenerational outcomes have rarely been studied. Here we investigate intergenerational effects of early environment in humans using survey- and clinic-based data from rural Gambia, a population experiencing substantial seasonal stress that influences foetal growth and has long-term effects on first-generation survival. Using Fourier regression to model seasonality, we test whether (i) parental birth season has intergenerational consequences for offspring in utero growth (1982 neonates, born 1976-2009) and (ii) whether such effects have been reduced by improvements to population health in recent decades. Contrary to our predictions, we show effects of maternal birth season on offspring birth weight and head circumference only in recent maternal cohorts born after 1975. Offspring birth weight varied according to maternal birth season from 2.85 to 3.03 kg among women born during 1975-1984 and from 2.84 to 3.41 kg among those born after 1984, but the seasonality effect reversed between these cohorts. These results were not mediated by differences in maternal age or parity. Equivalent patterns were observed for offspring head circumference (statistically significant) and length (not significant), but not for ponderal index. No relationships were found between paternal birth season and offspring neonatal anthropometrics. Our results indicate that even in rural populations living under conditions of relative affluence, brief variation in environmental conditions during maternal early life may exert long-term intergenerational effects on offspring.

A randomized trial to investigate the effects of pre-natal and infant nutritional supplementation on infant immune development in rural Gambia: the ENID trial: Early Nutrition and Immune Development

BACKGROUND

Recent observational research indicates that immune development may be programmed by nutritional exposures early in life. Such findings require replication from trials specifically designed to assess the impact of nutritional intervention during pregnancy on infant immune development. The current trial seeks to establish: (a) which combination of protein-energy (PE) and multiple-micronutrient (MMN) supplements would be most effective; and (b) the most critical periods for intervention in pregnancy and infancy, for optimal immune development in infancy.

METHODS/DESIGN

The ENID Trial is a 2 x 2 x 2 factorial randomized, partially blind trial to assess whether nutritional supplementation to pregnant women (from < 20 weeks gestation to term) and their infants (from 6 to 12 months of age) can enhance infant immune development. Eligible pregnant women from the West Kiang region of The Gambia (pregnancy dated by ultrasound examination) are randomized on entry to 4 intervention groups (Iron-folate (FeFol = standard care), multiple micronutrients (MMN), protein-energy (PE), PE + MMN). Women are visited at home weekly for supplement administration and morbidity assessment and seen at MRC Keneba at 20 and 30 weeks gestation for a detailed antenatal examination, including ultrasound. At delivery, cord blood and placental samples are collected, with detailed infant anthropometry collected within 72 hours. Infants are visited weekly thereafter for a morbidity questionnaire. From 6 to 12 months of age, infants are further randomized to a lipid-based nutritional supplement, with or without additional MMN. The primary outcome measures of this study are thymic development during infancy, and antibody response to vaccination. Measures of cellular markers of immunity will be made in a selected sub-cohort. Subsidiary studies to the main trial will additionally assess the impact of supplementation on infant growth and development to 24 months of age.

DISCUSSION

The proposed trial is designed to test whether nutritional repletion can enhance early immune development and, if so, to help determine the most efficacious form of nutritional support. Where there is evidence of benefit from a specific intervention/combination of interventions, future research should focus on refining the supplements to achieve the optimal, most cost-effective balance of interventions for improved health outcomes.

Early-life and contemporaneous nutritional and environmental predictors of antibody response to vaccination in young Gambian adults

Recent research links nutritional exposures early in life with alterations in functional immunity that persist beyond childhood. Here we investigate predictors of antibody response to polysaccharide vaccines in a cohort of Gambian adults with detailed records from birth and early infancy available. 320 adults were given a single dose of a Vi polysaccharide vaccine for Salmonella typhi and a 23-valent capsular polysaccharide pneumococcal vaccine. Anti-Vi antibody levels and antibodies against 4 pneumococcal serotypes (1, 5, 14 and 23F) were measured in serum samples collected at baseline and then 14 days following vaccination and compared to data available from birth and early infancy. Post-vaccination antibody titres to serotype 14 of the pneumococcal vaccine were negatively associated with rate of growth from birth to three months of age, infant weight at 12 months of age and season of birth, but no other associations were observed with early-life exposures. The strongest predictor of antibody levels was pre-vaccination antibody titres, with adult height and serum neopterin levels at time of vaccination also implicated. The current study does not support the hypothesis that nutritional exposures early in life consistently compromise antibody response to polysaccharide vaccines administered in young adulthood.

The kinetics of cell surface receptor expression in children perinatally exposed to polychlorinated biphenyls

Exposure to polychlorinated biphenyls (PCBs) during pre-natal and early life can alter normal immune system development. Blood specimens from newborns, 6-, and 16-month-old infants were collected in the Michalovce and Svidnik/Stropkov districts, areas with, respectively, high and low environmental PCB contamination, and lymphocyte receptor expression was evaluated by multi-color flow cytometry. The results indicate that the percentage of lymphoid dendritic cells (DC) and naïve/resting T-lymphocytes were significantly increased at 6-months in Michalovce as compared to the same cell types in cord blood samples (p < 0.001), whereas natural regulatory T-lymphocytes and suppressor inducer T-lymphocytes were reduced (p < 0.001). Overall, a positive linear correlation of terminally differentiated effector memory (TEM) T-lymphocyte population with age, but a negative linear correlation for myeloid DC from birth to 6-months in both regions were found. Michalovce samples indicated significantly higher expression of memory T-lymphocytes (birth, 6(th), and 16(th) month), TEM T-lymphocytes (birth and 6(th) month), and lymphoid DC (6(th) month) compared to the Svidnik/Stropkov regions. After adjustment for relevant covariates, such as maternal age, parity, season of birth, breastfeeding, birth weight, and gender, the myeloid DC, suppressor inducer T-lymphocytes, truly naïve helper/inducer T-lymphocytes, and TEM T-lymphocytes remained significantly different between districts in cord blood samples. The multivariate analysis models for 6- and 16-month samples showed district differences in all cellular determinants, except for lymphoid DC and macrophage-like cells. This study provides the first evidence that pre-natal and early post-natal exposure to PCBs affects the dynamics of cell surface receptor expression on lymphoid DC and DC-like cells, suggesting impaired immunologic development following pre-natal and early post-natal PCB exposure.

Prolonged exclusive breastfeeding, autumn birth and increased gestational age are associated with lower risk of fever in children with hand, foot, and mouth disease

Epidemics of hand, foot, and mouth disease (HFMD) have been emerging and reemerging in recent years. This study aims to investigate whether breastfeeding and other factors may affect the profile of fever and disease course in children with HFMD. Three hundred seventy-two preschool children with HFMD were included. The demographics, environmental factors, and delivery- and feeding-associated factors in the children were obtained and their effects on the profile of fever and disease course were analyzed. Of the 372 children, 139 (37.37%) had fever during the disease course. Gender, breastfeeding pattern, birth season and gestational age were significantly different between the children with and without fever (p = 0.034, p < 0.0001, p = 0.035 and p = 0.013, respectively). After multivariate-adjusted analysis, prolonged exclusive breastfeeding (p = 0.001, OR 0.401, 95% CI 0.229-0.704), autumn birth (p = 0.007, OR 0.409, 95% CI 0.214-0.784) and higher gestational age (p = 0.029, OR 0.089, 95% CI 0.010-0.781) were protective factors for the incidence of fever.

Dynamics of lymphocyte subsets in children living in an area polluted by polychlorinated biphenyls

Immune system development, particularly in the pre-natal and early post-natal periods, has far-reaching health consequences during childhood, as well as throughout life. Exposure to poly-chlorinated biphenyls (PCBs) during pre-natal and early life has been previously associated with changes in the incidence of infectious and allergic diseases in children, and humoral immunity alterations. Lymphocyte immunophenotyping is an important tool in the diagnosis of immunologic and hematologic disorders. This study used a lysed whole blood method for analysis of lymphocyte sub-populations in samples from children born and living in two districts: a highly-contaminated area (Michalovce) and one (Svidnik/Stropkov) with ≈ 2-fold lower environmental PCB levels. The percentages of B-lymphocytes (CD19(+)), activated HLADR(+)CD19(+) cells, and CD8(+) T-lymphocytes significantly increased at 6- and 16-months-of-age in both selected regions as compared to in cord blood values (p < 0.001). Levels of CD3(+) cells increased significantly (from 61 to 65%) in samples from Michalovce (p < 0.01). Levels of CD4(+) T-lymphocytes declined 10% among 16-month-olds in both regions (Michalovce at p < 0.001 and Svidnik/Stropkov at p < 0.01). Natural killer (NK) cell levels decreased 50% in Michalovce 6- and 16-month-old children and 42% among 6-month-olds in Svidnik/Stropkov (p < 0.001). Compared with the less-contaminated region, Michalovce samples showed significantly higher expression of CD3(+) T-lymphocytes, B-lymphocytes, and activated B-lymphocytes, whereas NK cells were less expressed. Even after adjustment for selected covariates, e.g., maternal cigarette smoking, age, parity, ethnicity, birth weight, and gender of infant, the levels of CD19(+), HLADR(+)CD19(+), and CD3(-)CD(16 + 56)(+) cells were seen to remain significantly different between the districts. These results showed that early-life environmental PCB exposure was associated with fluctuations in major lymphocyte subsets in children, suggesting that there is a post-natal immune system response to PCB exposures.

Measures of immune function of wild mice, Mus musculus

The immune function of wild animals has been rather little studied. Wild animals' immune function may differ from that of laboratory bred animals because of their different environments. This idea follows from the concept of resource partitioning in which animals distribute scarce resources to all aspects of life, including to costly immune responses. A logical extension of this idea is that there may be substantial interindividual variation in the immune function of wild animals. To begin to investigate this, we compared the immune function of a laboratory bred mouse strain (C57BL/6, a widely used mouse strain that makes potent immune responses) and wild caught Mus musculus. We found that by most measures of immune function, the wild caught mice had greater immune function. Specifically, wild mice had greater concentrations and more avid antigen-specific IgG responses, as well as higher concentrations of total IgG and IgE, compared with those laboratory bred mice. Moreover, flow cytometric analysis showed a comparatively greater overall level of activation of the cells of the immune system in wild mice. Lastly, we observed that immune function was substantially more variable among wild caught mice than among the laboratory bred mice. The next research challenge is to understand which aspects of an individual animal's life determine its immune function.

Patterns of fetal and infant growth are related to atopy and wheezing disorders at age 3 years

BACKGROUND

Little is known about whether patterns of early growth are associated with altered respiratory and immune development. This study relates prenatal and infant growth patterns to wheeze and atopy at age 3&emsp14;years.

METHODS

Birth weight and length were measured in 1548 children born at term. Conditional fetal head and abdominal circumference growth velocities were calculated from antenatal ultrasound measurements. Conditional postnatal growth velocities were calculated from infant weight, length and adiposity data. Measures of size and conditional growth were related to parentally-reported infant and early childhood wheeze and to atopic status at age 3 years.

RESULTS

The risk of atopy increased by 46% per SD increase in abdominal circumference growth velocity from 11 to 19 weeks gestation but by 20% per SD decrease in abdominal growth velocity from 19 to 34 weeks (p=0.007 and p=0.011, respectively). The risk of atopic wheeze increased by 20% per SD decrease in 19-34-week abdominal growth (p=0.046). The risk of non-atopic wheeze increased by 10% per SD decrease in 11-19-week head circumference growth. Greater relative infant weight and adiposity gains were associated with both atopic and non-atopic wheeze.

CONCLUSIONS

A rapid growth trajectory during 11-19 weeks gestation followed by late gestation growth faltering is associated with atopy, suggesting that influences affecting fetal growth may also alter immune development. A lower early fetal growth trajectory is associated with non-atopic wheeze, possibly reflecting an association with smaller airways. An association between postnatal adiposity gain and wheeze may partly reflect prenatal influences that cause fetal growth to falter but are then followed by postnatal adiposity gain.

Air pollution exposure during critical time periods in gestation and alterations in cord blood lymphocyte distribution: a cohort of livebirths

BACKGROUND

Toxic exposures have been shown to influence maturation of the immune system during gestation. This study investigates the association between cord blood lymphocyte proportions and maternal exposure to air pollution during each gestational month.

METHODS

Cord blood was analyzed using a FACSort flow cytometer to determine proportions of T lymphocytes (CD3+ cells and their subsets, CD4+ and CD8+), B lymphocytes (CD19+) and natural killer (NK) cells. Ambient air concentrations of 12 polycyclic aromatic hydrocarbons (PAH) and particulate matter < 2.5 micrometer in diameter (PM2.5) were measured using fixed site monitors. Arithmetic means of these pollutants, calculated for each gestational month, were used as exposure metrics. Data on covariates were obtained from medical records and questionnaires. Multivariable linear regression models were fitted to estimate associations between monthly PAH or PM2.5 and cord blood lymphocytes, adjusting for year of birth and district of residence and, in further models, gestational season and number of prior live births.

RESULTS

The adjusted models show significant associations between PAHs or PM2.5 during early gestation and increases in CD3+ and CD4+ lymphocytes percentages and decreases in CD19+ and NK cell percentages in cord blood. In contrast, exposures during late gestation were associated with decreases in CD3+ and CD4+ fractions and increases in CD19+ and NK cell fractions. There was no significant association between alterations in lymphocyte distribution and air pollution exposure during the mid gestation.

CONCLUSIONS

PAHs and PM2.5 in ambient air may influence fetal immune development via shifts in cord blood lymphocytes distributions. Associations appear to differ by exposure in early versus late gestation.

Perinatal nutrition and immunity to infection

Epidemiological data provide strong evidence for a relationship between undernutrition and life-threatening infection in infants and children. However, the mechanisms that underlie this relationship are poorly understood. Through foetal life, infancy and childhood, the immune system undergoes a process of functional maturation. The adequacy of this process is dependent on environmental factors, and there is accumulating evidence of the impact of pre- and post-natal nutrition in this regard. This review outlines the impact of nutrition during foetal and infant development on the capacity to mount immune responses to infection. It provides an overview of the epidemiologic evidence for such a role and discusses the possible mechanisms involved.