Young Children's Responses Research Articles

Cortisol reactivity in preschoolers at home and child care: Effects of setting in eliciting a normative stress response by child race/ethnicity

AbstractDevelopmental programming of the hypothalamic–pituitary–adrenal axis is theorized as a mechanism through which early life experiences are linked to later health outcomes. Despite the importance of understanding early stress responses, reliably eliciting stress responses in young children can be challenging. The current study measured salivary cortisol reactivity in a diverse sample of preschoolers. A standardized challenge paradigm was administered at home and at child care for each child, allowing for comparison of normative cortisol reactivity between settings. Results demonstrated that administration at home was associated with significant cortisol reactivity, while administration at child care was not. In comparison to white children, racially and ethnically diverse children exhibited lower cortisol reactivity in response to the home stressor. Results suggest that home‐based stress paradigms may be particularly effective at eliciting a stress response in this age range. Possible interpretations of differences by child race/ethnicity are discussed.Highlights Differential physiological responses to stress examined between home and childcare environments for a diverse sample of preschoolers. Significant cortisol reactivity was elicited at home but not at childcare, suggesting that home visits create a novel, naturalistic stressor for young children. Latinx and non‐Latinx minority children exhibited lower physiological reactivity in comparison to white children – cultural and methodological considerations are discussed.

Roles of culture and COMT Val58Met gene on neural basis of executive function: A comparison between Japanese and American children.

The development of executive functions (EF) is shaped by both genetic and environmental factors, including cultural background. Genetically, variation in the catechol-O-methyltransferase (COMT) gene polymorphism has been linked to EF performance and differential regulation of prefrontal cortex activity. Based on the gene-culture interaction framework, we tested whether culture would moderate the association between the COMT gene and young children's behavioral responses and neural activities during a cognitive-shifting EF task. The children who participated in this study were 5- to 6-year-olds in Japan (n=44) and in the U.S. (n=47). The results revealed that U.S.-American children exhibited stronger activations than Japanese children in the right dorsolateral and bilateral prefrontal cortex regions. In addition, the children's genetic disposition and EF performance were marginally moderated by culture, with Val homozygote Japanese children performing better than Met-allele carriers, whereas no such differences were found in U.S.-American children. We have discussed the theoretical and empirical implications of the construction of a more complete understanding of EF development by incorporating both genetic and socio-cultural factors.

Self‐regulated behavior and parent‐child co‐regulation are associated with young children's physiological response to receiving critical adult feedback

AbstractUsing piecewise growth curve trajectory modeling, we investigated kindergartners' physiological responses to receiving critical feedback from an adult during a laboratory drawing task. Further, we tested how children's independent self‐regulated behavior, as well as the quality of parent‐child co‐regulation, related to physiological reactivity to and recovery from this challenge. We used respiratory sinus arrhythmia (RSA) to measure parasympathetic nervous system activity. Participants were 96 children (Mage = 5.6 years, 56% female) and their parents. We used observer ratings to capture children's self‐regulated behavior during the laboratory visit and state‐space grid methodology (an innovative, moment‐to‐moment behavioral coding method) to index observed parent‐child positive co‐regulation during four interaction tasks. First, the quality of dyadic parent‐child co‐regulation was associated significantly with children's RSA reactivity during the dyadic experience of receiving critical feedback from an adult. Specifically, children with higher levels of positive parent‐child co‐regulation exhibited decreases in RSA while receiving critical feedback, which may indicate active engagement or coping with the challenging situation. Second, children's self‐regulated behavior was associated significantly with RSA recovery during a period immediately after the task ended, when children were seated alone. Children with lower levels of observed self‐regulated behavior showed sudden RSA decrease after the critical feedback ceased, suggesting that this post‐task period was physiologically challenging for them.

Risk and resilience of well-being in caregivers of young children in response to the COVID-19 pandemic.

The COVID-19 pandemic is impacting communities worldwide, with direct effects of illness and mortality, and indirect effects on economies, workplaces, schools/daycares, and social life. However, we understand very little about the effects of this pandemic on families of young children. We used a risk and resilience model to evaluate the effects of the pandemic on mental health in diverse caregivers (N = 286) with children ages birth to 5. We evaluated the hypotheses that (a) pandemic stress and caregiver-reported child psychosocial concerns correlate with caregivers’ mental health symptoms and (b) caregivers’ pandemic-related self-efficacy and coping mediate these relationships. Caregivers completed surveys in April–May 2020 assessing pandemic stress (e.g., health, finances, and housing), child psychosocial problems, coping strategies, and self-efficacy to manage family needs. Our primary outcome was caregivers’ self-reported changes in mental health symptoms since the outbreak. Path analysis revealed that higher pandemic stress was associated with caregivers’ reduced confidence in meeting their family’s needs related to COVID-19, which correlated with worse caregiver mental health symptoms. Greater child psychosocial problems also predicted worse caregiver mental health symptoms. Findings suggest that pandemic stress, child psychosocial problems, and caregiver self-efficacy are interrelated in their influence on caregivers’ mental health. While further research is needed to examine strategies to foster resilience and buffer the pandemic’s effects on caregiver mental health, this is a first step in evaluating the psychosocial effects of this pandemic in families of young children. Clinical implications are discussed for a tiered response to mitigate the pandemic’s impacts on family functioning.

Emotion socialization – compassion or non-engagement – in young children's responses to peer distress

Abstract Taking its point of departure from sociocultural perspectives, the present study examines 2–3-year-old children's responses to peers' crying in a regular Swedish preschool. By analyzing video recordings of the children's everyday activities and frequent situations of crying in peer play conflicts, the study identifies the broad range of children's responses to peer distress. Children's orientation towards a crying peer is discussed in relation to their social concerns, relationships, and the institutional characteristics of preschool play activities. The children's most common orientation to peer's crying was to stay away from the child in distress by simply observing him (looking at him), or by continuing play. Children actively engaged with the crying child by continuing the conflict or, on rare occasions, showing compassion (trying to verbally and nonverbally alleviate the crying child's distress). Children's responses to peer's crying are discussed in terms of collective socialization practices, related to children's peer group play concerns, and institutional concerns of educators. We argue that responses to children's crying constitute sites for emotion and moral socialization and (re)-produce specific cultural values about compassionate conduct, the normative appropriateness of crying, and caregiver–child responsibilities for alleviating another's distress.

Imitation in Angelman syndrome: the role of social engagement

Individuals with Angelman syndrome (AS) are characterized by severe cognitive impairments alongside an enhanced drive for social engagement. As knowledge on imitation skills in this population is limited, we conducted the first controlled study of imitation in AS. We examined how 23 individuals with AS and 21 typically developing young children with similar mental age imitated novel actions in response to socially or non-socially engaging models, and in response to video-recorded versus live demonstrations of novel actions. Individuals with AS imitated as frequently and as accurately as typical young children in response to live demonstrations; but they imitated less frequently and less accurately in response to video-recorded demonstrations. Further, imitation was modulated by whether the demonstrator was socially engaging or emotionally neutral in the AS group, while this modulation was not present in the comparison group. Individuals with higher mental age imitated more frequently and more accurately across groups. Imitation performance in AS appears to be more modulated by the social context compared to typical infants and young children with similar mental age, possibly reflecting an enhanced drive for social engagement. A socially engaging instructional style might facilitate imitative learning in this population.

Cross-talk between airway and gut microbiome links to IgE responses to house dust mites in childhood airway allergies

A connection between airway and gut microbiota related to allergen exposure in childhood allergies was not well addressed. We aimed to identify the microbiota alterations in the airway and gut related to mite-specific IgE responses in young children with airway allergies. This study enrolled 60 children, including 38 mite-sensitized children (20 rhinitis and 18 asthma), and 22 non-mite-sensitized healthy controls. Microbiome composition analysis of the throat swab and stool samples was performed using bacterial 16S rRNA sequencing. An integrative analysis of the airway and stool microbial profiling associated with IgE reactions in childhood allergic rhinitis and asthma was examined. The Chao1 and Shannon indices in the airway were significantly lower than those in the stool. Additionally, an inverse association of the airway microbial diversity with house dust mite (HDM) sensitization and allergic airway diseases was noted. Fecal IgE levels were positively correlated with the serum Dermatophagoides pteronyssinus- and Dermatophagoides farinae-specific IgE levels. Airway Leptotrichia spp. related to asthma were strongly correlated with fecal Dorea and Ruminococcus spp., which were inversely associated with fecal IgE levels and risk of allergic rhinitis. Moreover, four airway genera, Campylobacter, Selenomonas, Tannerella, and Atopobium, were negatively correlated with both serum mite-specific and fecal IgE levels. Among them, the airway Selenomonas and Atopobium spp. were positively correlated with stool Blautia and Dorea spp. related to asthma and allergic rhinitis, respectively. In conclusion, airway microbial dysbiosis in response to HDM and its cross-talk with the gut microbial community is related to allergic airway diseases in early childhood.

One additional shot of brachial plexus block equates to less postoperative pain for younger children with elbow surgeries

BackgroundPostoperative pain in children has always been inadequately evaluated. This study aims to evaluate the postoperative pain response using an additional dose of brachial plexus block (BPB) for younger children receiving elbow surgeries under general anesthesia (GA).MethodsThis retrospective case-control study included pediatric patients (3–10 years) who underwent surgeries for elbow injuries between January 2015 and January 2019. Patients with previous history of surgeries around the elbow, neurological impairment of injured limb, polytrauma, undergoing pain management for different causes, and open or old fractures were excluded. Patients were dichotomized into the GA group and the GA + BPB group as per the presence or absence of BPB.ResultsIn all, 150 patients (102/48, male/female) in the GA and 150 patients (104/46, male/female) in the GA + BPB group were included. There existed no significant differences between the two groups in age, sex, fracture side, and types of elbow procedures. As for the pain response after lateral condyle fracture of the humerus (LCFH), the FLACC pain scale was significantly higher for those in the GA group (6.2 ± 0.8) when compared to the GA + BPB group (1.6 ± 0.5) (P < 0.001). As for the pain response after medial epicondyle fracture of the humerus (MCFH), the FLACC pain scale was significantly higher for those in the GA group (6.0 ± 0.8) when compared to the GA + BPB group (1.5 ± 0.5) (P < 0.001). As for the pain response after supracondylar fracture of the humerus (SCFH), the FLACC pain scale was significantly higher for those in the GA group (6.0 ± 0.8) when compared to the GA + BPB group (1.6 ± 0.5) (P < 0.001). As for the pain response after cubitus varus correction, the FLACC pain scale was significantly higher for those in the GA group (6.7 ± 0.7) when compared to the GA + BPB group (2.1 ± 0.7) (P < 0.001).ConclusionAn additional shot of BPB for patients undergoing surgeries for elbow surgeries resulted in better postoperative pain response in younger children without significant BPB-related complications.

The CD4+ T Cell Response to Human Cytomegalovirus in Healthy and Immunocompromised People.

While CD8+ T cells specific for human cytomegalovirus (HCMV) have been extensively studied in both healthy HCMV seropositive carriers and patients undergoing immunosuppression, studies on the CD4+ T cell response to HCMV had lagged behind. However, over the last few years there has been a significant advance in our understanding of the importance and contribution that CMV-specific CD4+ T cells make, not only to anti-viral immunity but also in the potential maintenance of latently infected cells. During primary infection with HCMV in adults, CD4+ T cells are important for the resolution of symptomatic disease, while persistent shedding of HCMV into urine and saliva is associated with a lack of HCMV specific CD4+ T cell response in young children. In immunosuppressed solid organ transplant recipients, a delayed appearance of HCMV-specific CD4+ T cells is associated with prolonged viremia and more severe clinical disease, while in haematopoietic stem cell transplant recipients, it has been suggested that HCMV-specific CD4+ T cells are required for HCMV-specific CD8+ T cells to exert their anti-viral effects. In addition, adoptive T-cell immunotherapy in transplant patients has shown that the presence of HCMV-specific CD4+ T cells is required for the maintenance of HCMV-specific CD8+ T cells. HCMV is a paradigm for immune evasion. The presence of viral genes that down-regulate MHC class II molecules and the expression of viral IL-10 both limit antigen presentation to CD4+ T cells, underlining the important role that this T cell subset has in antiviral immunity. This review will discuss the antigen specificity, effector function, phenotype and direct anti-viral properties of HCMV specific CD4+ T cells, as well as reviewing our understanding of the importance of this T cell subset in primary infection and long-term carriage in healthy individuals. In addition, their role and importance in congenital HCMV infection and during immunosuppression in both solid organ and haemopoietic stem cell transplantation is considered.

Technologies for assessing vaccine responses in the very young.

Many vaccines are administered to young children in order to prevent infectious diseases early in life. At the same time, most of these vaccines are not developed specifically with the immune system of young children in mind and our understanding of how newborn immune systems differ from adult counterparts is incomplete. The main reason for this lack of understanding stems from the ethical and logistical difficulties in obtaining samples from young children as well as the challenges associated with the small volume samples available. Here I review some recent developments made in this field and discuss their implications for studying vaccine responses in young children and developing better vaccines, tailored to this important population of susceptible individuals in the future.

Molecular Biomarkers Predictive of Sertraline Treatment Response in Young Children With Autism Spectrum Disorder.

Sertraline is one among several selective serotonin reuptake inhibitors (SSRIs) that exhibited improvement of language development in Autism Spectrum Disorder (ASD); however, the molecular mechanism has not been elucidated. A double blind, randomized, 6-month, placebo-controlled, clinical trial of low-dose sertraline in children ages (3–6 years) with ASD was conducted at the UC Davis MIND Institute. It aimed at evaluating the efficacy and benefit with respect to early expressive language development and global clinical improvement. This study aimed to identify molecular biomarkers that might be key players in the serotonin pathway and might be predictive of a clinical response to sertraline. Fifty eight subjects with the diagnosis of ASD were randomized to sertraline or placebo. Eight subjects from the sertraline arm and five from the placebo arm discontinued from the study. Furthermore, four subjects did not have a successful blood draw. Hence, genotypes for 41 subjects (20 on placebo and 21 on sertraline) were determined for several genes involved in the serotonin pathway including the serotonin transporter-linked polymorphic region (5-HTTLPR), the tryptophan hydroxylase 2 (TPH2), and the Brain-Derived Neurotrophic Factor (BDNF). In addition, plasma levels of BDNF, Matrix metallopeptidase 9 (MMP-9) and a selected panel of cytokines were determined at baseline and post-treatment. Intent-to-treat analysis revealed several primary significant correlations between molecular changes and the Mullen Scales of Early Learning (MSEL) and Clinical Global Impression Scale – Improvement (CGI-I) of treatment and control groups but they were not significant after adjustment for multiple testing. Thus, sertraline showed no benefit for treatment of young children with ASD in language development or changes in molecular markers in this study. These results indicate that sertraline may not be beneficial for the treatment of children with ASD; however, further investigation of larger groups as well as longer term follow-up studies are warranted.

Comparison of a glycoprotein E-based ELISA with a varicella-zoster whole-virus ELISA for the quantification of varicella vaccine immune responses in young children

Antibody response against varicella-zoster virus (VZV) is frequently assessed by whole-virus- (anti-VZV) or glycoprotein-based ELISAs. This study compared antibody concentrations measured by an assay quantifying anti-VZV glycoprotein E (anti-gE) and anti-VZV ELISA in 12–23-month-olds, receiving two varicella vaccine doses in a phase III trial (NCT02570126). Samples (pre- and 42 days post-each vaccination) initially tested with anti-VZV ELISA were re-tested with anti-gE ELISA. Of 1138 samples from 397 children, 757 were positive by anti-VZV (antibody concentration ≥25 mIU/mL) and 758 by anti-gE ELISA (≥97 mIU/mL). There were 375 double-negative and only 11 discrepant samples. The overall agreement was 99.03% (95% confidence interval: 98.28–99.52; McNemar p-value = 1). The ratio between antibody geometric mean concentrations (anti-gE/anti-VZV) for the 752 double-positive samples was 3.78 overall, 4.75 post-first, and 3.01 post-second vaccination. The anti-gE ELISA is a valid alternative for trials assessing antibody response to new varicella vaccines versus established ones, used as control.

Social responsiveness and language use associated with an enhanced PRT approach for young children with ASD: Results from a pilot RCT of the PRISM model

BackgroundVulnerabilities in social motivation among children with ASD constrain attention and responsiveness to parents and other social partners. When this limited social responsiveness remains uncorrected, it is hypothesized to restrict the quality and quantity of social learning opportunities and ultimately yield negative long-term effects on development. Early intervention efforts that target social motivation may hold promise for correcting this detrimental chain of events. MethodThe current pilot RCT examined changes in participant social responsiveness and language use in a trial of 21 young children with ASD who were randomly assigned to treatment or waitlist control groups. Treatment participants received a mean of 6.81 h/week of an enhanced Pivotal Response Intervention for Social Motivation (PRISM) treatment model for six months. Data on social responsiveness to parent bids and expressive language (number of total words, number of different words, mean length of utterance in words) were obtained from behaviorally coding and analyzing video-recorded parent-child play sessions. ResultsResults indicated that young children who participated in the PRISM treatment model demonstrated significant pre-post improvements in social responsiveness and mean length of utterances. Participants in the waitlist condition experienced negligible improvements. Participants who are minimally verbal appear to experience greater gains as a result of the PRISM model. Additionally, initial levels of social responsiveness with parents appear to be predictive of subsequent language use at post-intervention among minimally verbal participants. ConclusionThis study provides preliminary evidence for the importance of using early intervention paradigms that explicitly target social motivation and responsiveness in young children with ASD. Results also suggest that initial social responsiveness to parents may serve as an important predictor of treatment response.

Fear in infancy: Lessons from snakes, spiders, heights, and strangers.

This review challenges the traditional interpretation of infants' and young children's responses to three types of potentially "fear-inducing" stimuli-snakes and spiders, heights, and strangers. The traditional account is that these stimuli are the objects of infants' earliest developing fears. We present evidence against the traditional account, and provide an alternative explanation of infants' behaviors toward each stimulus. Specifically, we propose that behaviors typically interpreted as "fearful" really reflect an array of stimulus-specific responses that are highly dependent on context, learning, and the perceptual features of the stimuli. We speculate about why researchers so commonly misinterpret these behaviors, and conclude with future directions for studying the development of fear in infants and young children. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

한국화와 서양화의 비교감상 활동에 나타난 유아 반응과 교육적 의미에 관한 연구

본 연구는 한국화와 서양화의 비교감상 활동에서 나타난 유아의 반응과 한국화와 서양화의 비교감상 활동이 유아에게 미치는 교육적 의미를 찾는 것에 목적을 두었다. 연구 대상은 W시에 소재한 공립유치원 만5세 유아들이며, 남 · 여아 각 9명씩 모두 18명이고, 연구 기간은 2018년 4월 2일～7월 20일까지 총12회에 걸쳐 한국화와 서양화의 비교감상 활동을 실시하였다. 유아들의 한국화와 서양화의 비교감상 활동을 통한 그림 변화에 대한 심도 있는 접근을 위해 질적 연구방법을 사용하였다. 연구결과로 첫째, 한국화와 서양화의 비교감상 활동 과정에서 유아들은 한국화와 서양화에 대한 이미지를 비교하고, 비교감상 활동을 통해 주고받은 유아들 간 상호작용이 자연스럽게 맥락에 맞는 이야기 찾아내기를 도모하는 것으로 나타났다. 둘째, 유아의 미적요소에 의한 미술 표현력, 유아의 창의성, 유아의 정서적 표현력이 신장되는 것으로 나타났다. 본 연구결과를 통해, 한국화와 서양화의 비교감상 활동이 미술감상 교육을 위한 새로운 방안이 될 수 있음을 시사한다.

Change and Continuity in Low-Income Working Mothers' Food Practices for Young Children in Response to Life Events.

To understand how changes in low-income mothers' work, home, and childcare environments impact their food practices for young children. The grounded theory, theory-guided, design included two in-depth qualitative interviews (6 to 8months apart) with each of 19 low income, working/student mothers of Head Start children, living in a rural county in Upstate New York. Interviews covered mothers' experiences of employment, school, family, household, and childcare events over one school year and whether and how events changed child food practices. Emergent themes related to mothers' experiences of life events, with attention to influences on child food practices, were open-coded using a constant comparative approach. A life course approach and a transactional model of the stress process informed interpretation. Within the study period, most mothers reported at least one life event, with many experiencing one or more changes in employers, job schedules, residence, household members, or childcare situation. Emergent patterns of adjustment in child food practices linked with life events were shaped by mothers' appraisals of life events, the availability of coping resources, and their adaptations to events, based on temporal, financial, and social resources. The findings support a view of child feeding informed by the transactional model of stress. Instability in work, family, household, and childcare highlight changing contexts for child food practices in daily life. Research and practice should acknowledge the changing nature of the child feeding context and the need for children's caregivers to make adjustments in response to changing resources.

Young children integrate current observations, priors and agent information to predict others' actions.

From early on in life, children are able to use information from their environment to form predictions about events. For instance, they can use statistical information about a population to predict the sample drawn from that population and infer an agent’s preferences from systematic violations of random sampling. We investigated whether and how young children infer an agent’s sampling biases. Moreover, we examined whether pupil data of toddlers follow the predictions of a computational model based on the causal Bayesian network formalization of predictive processing. We formalized three hypotheses about how different explanatory variables (i.e., prior probabilities, current observations, and agent characteristics) are used to predict others’ actions. We measured pupillary responses as a behavioral marker of ‘prediction errors’ (i.e., the perceived mismatch between what one’s model of an agent predicts and what the agent actually does). Pupillary responses of 24-month-olds, but not 18-month-olds, showed that young children integrated information about current observations, priors and agents to make predictions about agents and their actions. These findings shed light on the mechanisms behind toddlers’ inferences about agent-caused events. To our knowledge, this is the first study in which young children's pupillary responses are used as markers of prediction errors, which were qualitatively compared to the predictions by a computational model based on the causal Bayesian network formalization of predictive processing.

Cumulative clinical experience with MF59-adjuvanted trivalent seasonal influenza vaccine in young children

ObjectiveTo demonstrate the potential of an MF59-adjuvanted inactivated trivalent seasonal influenza vaccine (aIIV3; Fluad™) to improve the immune response in young children, we review the immunogenicity, efficacy, and safety/tolerability of aIIV3 from a comprehensive clinical development program in a pediatric population with a specific need for improved influenza vaccines. MethodsData were analyzed from a series of 1 phase Ib, 3 phase II, and 2 phase III studies involving 11,942 children aged 6 months through 5years. ResultsThe clinical data showed that aIIV3 had statistically significantly greater immunogenicity and efficacy in the prevention of influenza compared to conventional inactivated trivalent seasonal influenza vaccines (IIV3s). The safety profile of aIIV3 was generally similar to that of nonadjuvanted IIV3, apart from an increased frequency of solicited adverse events (AEs) following vaccination. The majority of solicited AEs were mild or moderate in severity and resolved within 1 to 3 days. ConclusionsaIIV3 was well tolerated, with immunogenicity and efficacy exceeding that of conventional IIV3 in children 6 months through 5years of age. The MF59-adjuvanted vaccine has the potential to fulfill an unmet clinical need in the prevention of seasonal influenza in this age group.

Hair cortisol as a measure of the stress response to social adversity in young children.

Hair cortisol has the potential to provide insight into young children's long-term stress response to social adversity. This study investigated associations between children's exposure to adversity from pregnancy to 2years of age and their hair cortisol at 2years, using a longitudinal cohort of children enriched for adversity risk, whose mothers were recruited during pregnancy through the "right@home" trial. Exposures were 18 maternal socioeconomic and psychosocial indicators of adversity, examined as concurrent, cumulative, and longitudinal exposure from pregnancy to 2years. Hair samples were analyzed from 319/603 (53%) children participating at 2years. Multivariable regression analyses for concurrent exposure showed three indicators of adversity were associated with higher hair cortisol (housing tenure of public rental, paying board or living rent free; not living in a safe place; higher maternal stress symptoms), one with lower hair cortisol (housing problems), and 14 indicators with no evidence of association. There was no evidence of association for the cumulative adversity count. Longitudinal exposure showed "intermittent" and "persistent" high maternal stress symptoms were associated with higher hair cortisol. The small number of associations identified suggests that hair cortisol is limited as a measure of stress response to social adversity in children at 2years.

Lactobacillus plantarum IS-10506 supplementation increases faecal sIgA and immune response in children younger than two years.

The immature intestinal immune system in young children develops as it comes into contact with dietary and microbial antigens in the gut. Intestinal microbiota plays a significant role in host defence mechanisms as shown by inflammatory responses towards potential pathogens. We investigated the probiotic function of Lactobacillus plantarum IS-10506 of 'dadih' origin in modulating immune response in young children. We aimed to assess its effect on their immune response by assessing transforming growth factor-β1 (TGF-β1) and tumour necrosis factor-α (TNF-α) responses and faecal secretory immunoglobulin A (sIgA) titre in a randomised, double-blinded placebo-controlled trial in 12-24-month-old children (n=38). We used four treatment groups for a 90-day supplementation period: placebo (n=11), probiotic (n=9), zinc (n=8) and probiotic and zinc (n=10). Faecal sIgA, plasma TGF-β1 and TNF-α titre were evaluated using the enzyme-linked immunosorbent assay standard technique. Statistical analysis divided the results (pre/post treatment) into high (>1) and low (<1) ratios. The results showed that faecal sIgA titre increased in all treatment groups compared with the control (placebo) and significantly increased in the probiotic group (P=0.05). In addition, the TGF-β1 ratio in the zinc group was significantly higher (P=0.05) than that in the placebo group. We observed a significant positive correlation between TGF-β1/TNF-α and faecal sIgA (r=0.27, P=0.04). Post hoc test results revealed that zinc supplementation has a significant effect on body-weight gain. Taken together, probiotic L. plantarum IS-10506 supplementation stimulates TGF-β1, which in turn increases the production of sIgA, in line with the significant correlation between TGF-β1/TNF-α and faecal sIgA.