Immunoglobulins in saliva of preterm and full-term infants

Salivary Protein and Electrolyte Profiles during Primary Teeth Eruption: A Cross-Sectional Study

This study aimed to assess the qualitative changes in the saliva during the process of primary teeth eruption. This cross-sectional study was conducted on 147 children from 2 to 48 months, of which 49 were in group A (no erupted primary teeth), 53 were in group B (at least one active erupting primary tooth), and 45 were in group C (eruption of all 20 primary teeth was completed). Salivary proteins were evaluated by sodium dodecyl sulfate electrophoresis with polyacrylamide gel, while the concentrations of salivary sodium, potassium, chloride, and calcium ions were evaluated by ion selective electrodes. The data were analyzed using ANOVA and Bonferroni tests (alpha = 0.05). The concentration of proteins with molecular weights of 20-30 KDa was significantly higher in group A, and it gradually decreased with age. The concentration of proteins with molecular weights of 50-60 KDa in group B was significantly lower than those of groups A and C. The calcium ion concentration in group A was significantly higher than that of the other groups. The concentration of potassium ions was minimal in group C. The proteins and electrolyte profiles of the subjects' saliva changed in the process of primary tooth eruption. The highest concentrations of proteins such as statherin, histatin, P-B peptide, and cystatin and the lowest concentrations of proteins such as amylase were present in group B.

A Critical Review on the Standardization and Quality Assessment of Nonfunctional Laboratory Tests Frequently Used to Identify Inborn Errors of Immunity

Inborn errors of immunity (IEI), which were previously termed primary immunodeficiency diseases, represent a large and growing heterogeneous group of diseases that are mostly monogenic. In addition to increased susceptibility to infections, other clinical phenotypes have recently been associated with IEI, such as autoimmune disorders, severe allergies, autoinflammatory disorders, benign lymphoproliferative diseases, and malignant manifestations. The IUIS 2019 classification comprises 430 distinct defects that, although rare individually, represent a group affecting a significant number of patients, with an overall prevalence of 1:1,200-2,000 in the general population. Early IEI diagnosis is critical for appropriate therapy and genetic counseling, however, this process is deeply dependent on accurate laboratory tests. Despite the striking importance of laboratory data for clinical immunologists, several IEI-relevant immunoassays still lack standardization, including standardized protocols, reference materials, and external quality assessment programs. Moreover, well-established reference values mostly remain to be determined, especially for early ages, when the most severe conditions manifest and diagnosis is critical for patient survival. In this article, we intend to approach the issue of standardization and quality control of the nonfunctional diagnostic tests used for IEI, focusing on those frequently utilized in clinical practice. Herein, we will focus on discussing the issues of nonfunctional immunoassays (flow cytometry, enzyme-linked immunosorbent assays, and turbidimetry/nephelometry, among others), as defined by the pure quantification of proteins or cell subsets without cell activation or cell culture-based methods.

Effects of the intake of non-live Bifidobacterium bifidum on the faecal IgA of full-term infants: a double-blind, randomised, placebo-controlled study

Bifidobacterium bifidum OLB6378 (OLB6378) was selected as a strain that enhances the production of secretory immunoglobulin A (IgA) in vitro. This ability of non-live OLB6378 has been shown by a clinical trial in preterm infants. In the present study, we examined whether non-live OLB6378 also enhances the production of secretory IgA, even in full-term infants. One hundred full-term infants were allocated to receive formula with (BbF group, 49 infants) or without non-live OLB6378 (PF group, 51 infants). Breastfeeding was prioritised, so infant formula was used for infants with breastfeeding difficulties. The intervention was initiated by five days of age. The faecal IgA concentration and OLB6378 level were determined at one, two, four, and eight weeks of age. Faecal IgA in the BbF group (1.04 ± 0.47 mg/g of faeces, n=45) was significantly higher than that in the PF group (0.85 ± 0.42 mg/g of faeces, n=49) at four weeks of age (p=0.047). OLB6378 was not detected in faeces at any age. This indicated that production of secretory IgA in full-term infants may also be enhanced by non-live OLB6378 intake.

Severe respiratory syncytial virus disease in preterm infants: a case of innate immaturity

Respiratory syncytial virus (RSV) is the most common viral pathogen associated with acute lower respiratory tract infection (LRTI) in children under 5 years of age. Severe RSV disease is associated with the development of chronic respiratory complications such as recurrent wheezing and asthma. A common risk factor for developing severe RSV disease is premature gestation and this is largely due to an immature innate immune system. This increases susceptibility to RSV since the innate immune system is less able to protect against pathogens at a time when adaptive immunity has not fully developed. This review focuses on comparing different aspects of innate immunity between preterm and term infants to better understand why preterm infants are more susceptible to severe RSV disease. Identifying early life innate immune biomarkers associated with the development of severe RSV disease, and understanding how these compare between preterm and term infants, remains a critically important question that would aid the development of interventions to reduce the burden of disease in this vulnerable population.

Longitudinal analysis of the salivary metabolome of breast-fed and formula-fed infants over the first year of life

INTRODUCTION

The salivary metabolome has been increasingly studied over the past ten years due to the potential of saliva as a non-invasive source of biomarkers. However, although saliva has been studied in relation to various diseases, its dynamic evolution during life is not known. This is particularly true for the first months of life. Infancy is indeed a critical period during which numerous behavioural and physiological events occur, such as dietary transitions and tooth eruption, which can lead to important biological modifications in the oral cavity.

OBJECTIVES

The aim of this work was therefore to study the evolution of the salivary metabolome during the first months of life by ¹H NMR.

METHODS

Saliva of 32 infants with different milk feeding histories (breast vs formula) was collected at 6 stages, including 3 months old, 15 days before the onset of complementary feeding (CF), approximately 15 days after the onset of CF, approximately 21 days after the onset of CF and at approximately 11 and 15 months, and analysed.

RESULTS

The longitudinal analysis showed a significant modification of the profiles of 18 metabolites over time; 14 presented an increase in abundance whereas 4 presented a decrease. These modifications seemed to be linked, for the most part, to an increase in oral microbial metabolism. Milk feeding history during the first months of life had no effect on metabolites.

CONCLUSION

This work shows that the salivary metabolome should be considered when studying the changes occurring during infancy.

Modulatory effect of three probiotic strains on infants' gut microbial composition and immunological parameters on a placebo-controlled, double-blind, randomised study

The gut microbiota plays a crucial role in gastrointestinal health. Current use of probiotics is aimed at modulating the bacterial gut composition to alleviate specific diseases. The safety and tolerance of three probiotic strains (Bifidobacterium longum subsp. infantis R0033, Lactobacillus helveticus R0052 and Bifidobacterium bifidum R0071) has recently been described. The objective of the present study was to analyse the microbiological composition and immunological parameters of faecal samples obtained from healthy infants from 3 to 12 months of age after receiving either one of the three probiotic strains or placebo for 8 weeks. 16S ribosomal RNA gene sequencing and multiplexing technology was used for analysis. Faecal sample analysis showed that the most abundant genus in all four groups of infants pre- and post-intervention was Bifidobacterium, representing approximately 50% of the sequences. After the intervention period the microbial composition of faecal samples in the probiotic groups did not display notable changes. In contrast, a decrease in different Bifidobacterium species, such as B. bifidum and Bifidobacterium breve and an increase in Bacteroides, Blautia, Clostridium, Coprococcus and Faecalibacterium genera was observed in the placebo group. The analysis of a wide range of immune factors in faecal samples suggests a modulatory effect by these three probiotic strains during the intervention period. The anti-inflammatory ratio interleukin (IL)-10/IL-12 increased at the end of the intervention period in the B. infantis R0033 group while the TNF-α/IL-10 ratio increased in the L. helveticus R0052 group. The decrease of the IL-10/IL-12 ratio together with the increase of the tumour necrosis factor alpha (TNF-α)/IL-10 ratio demonstrated a pro-inflammatory profile in the placebo group. In conclusion, the species profile of the microbiome observed in all three probiotic groups resembled that of a younger infant, similar to an unweaned infant, when compared to the placebo group which may also be related with an anti-inflammatory effect.

Assessing the stability of polio eradication after the withdrawal of oral polio vaccine

The oral polio vaccine (OPV) contains live-attenuated polioviruses that induce immunity by causing low virulence infections in vaccine recipients and their close contacts. Widespread immunization with OPV has reduced the annual global burden of paralytic poliomyelitis by a factor of 10,000 or more and has driven wild poliovirus (WPV) to the brink of eradication. However, in instances that have so far been rare, OPV can paralyze vaccine recipients and generate vaccine-derived polio outbreaks. To complete polio eradication, OPV use should eventually cease, but doing so will leave a growing population fully susceptible to infection. If poliovirus is reintroduced after OPV cessation, under what conditions will OPV vaccination be required to interrupt transmission? Can conditions exist in which OPV and WPV reintroduction present similar risks of transmission? To answer these questions, we built a multi-scale mathematical model of infection and transmission calibrated to data from clinical trials and field epidemiology studies. At the within-host level, the model describes the effects of vaccination and waning immunity on shedding and oral susceptibility to infection. At the between-host level, the model emulates the interaction of shedding and oral susceptibility with sanitation and person-to-person contact patterns to determine the transmission rate in communities. Our results show that inactivated polio vaccine (IPV) is sufficient to prevent outbreaks in low transmission rate settings and that OPV can be reintroduced and withdrawn as needed in moderate transmission rate settings. However, in high transmission rate settings, the conditions that support vaccine-derived outbreaks have only been rare because population immunity has been high. Absent population immunity, the Sabin strains from OPV will be nearly as capable of causing outbreaks as WPV. If post-cessation outbreak responses are followed by new vaccine-derived outbreaks, strategies to restore population immunity will be required to ensure the stability of polio eradication.

Oral polio vaccine (OPV) has played an essential role in the elimination of wild poliovirus (WPV). OPV contains attenuated (weakened) yet transmissible viruses that can spread from person to person. In its attenuated form, this spread is beneficial as it generates population immunity. However, the attenuation of OPV is unstable and it can, in rare instances, revert to a virulent form and cause vaccine-derived outbreaks of paralytic poliomyelitis. Thus, OPV is both a vaccine and a source of poliovirus, and for complete eradication, its use in vaccination must be ended. After OPV is no longer used in routine immunization, as with the cessation of type 2 OPV in 2016, population immunity to polioviruses will decline. A key question is how this loss of population immunity will affect the potential of OPV viruses to spread within and across communities. To address this, we examined the roles of immunity, sanitation, and social contact in limiting OPV transmission. Our results derive from an extensive review and synthesis of vaccine trial data and community epidemiological studies. Shedding, oral susceptibility to infection, and transmission data are analyzed to systematically explain and model observations of WPV and OPV circulation. We show that in high transmission rate settings, falling population immunity after OPV cessation will lead to conditions in which OPV and WPV are similarly capable of causing outbreaks, and that this conclusion is compatible with the known safety of OPV prior to global cessation. Novel strategies will be required to ensure the stability of polio eradication for all time.

Bacteriological and Immunological Profiling of Meconium and Fecal Samples from Preterm Infants: A Two-Year Follow-Up Study

An abnormal colonization pattern of the preterm gut may affect immune maturation and exert a long-term influence on the intestinal bacterial composition and host health. However, follow-up studies assessing the evolution of the fecal microbiota of infants that were born preterm are very scarce. In this work, the bacterial compositions of fecal samples, obtained from sixteen 2-year-old infants were evaluated using a phylogenetic microarray; subsequently, the results were compared with those obtained in a previous study from samples of meconium and feces collected from the same infants while they stayed in the neonatal intensive care unit (NICU). In parallel, the concentration of a wide range of cytokines, chemokines, growth factors and immunoglobulins were determined in meconium and fecal samples. Globally, a higher bacterial diversity and a lower interindividual variability were observed in 2-year-olds' feces, when compared to the samples obtained during their first days of life. Hospital-associated fecal bacteria, that were dominant during the NICU stay, seemed to be replaced, two years later, by genera, which are usually predominant in the healthy adult microbiome. The immune profile of the meconium and fecal samples differed, depending on the sampling time, showing different immune maturation statuses of the gut.

Maternal immunisation: collaborating with mother nature

Maternal immunisation has the potential to substantially reduce morbidity and mortality from infectious diseases after birth. The success of tetanus, influenza, and pertussis immunisation during pregnancy has led to consideration of additional maternal immunisation strategies to prevent group B streptococcus and respiratory syncytial virus infections, among others. However, many gaps in knowledge regarding the immunobiology of maternal immunisation prevent the optimal design and application of this successful public health intervention. Therefore, we did an innovative landscape analysis to identify research priorities. Key topics were delineated through review of the published literature, consultation with vaccine developers and regulatory agencies, and a collaborative workshop that gathered experts across several maternal immunisation initiatives-group B streptococcus, respiratory syncytial virus, pertussis, and influenza. Finally, a global online survey prioritised the identified knowledge gaps on the basis of expert opinion about their importance and relevance. Here we present the results of this worldwide landscape analysis and discuss the identified research gaps.

Salivary Immunoglobulin Gene Expression in Patients with Caries

BACKGROUND:

Immunoglobulins mediate the host’s humoral immune response are expressed in saliva.

AIM:

To quantify the FcαR, FcγRIIB, and FcαμR gene expression in the saliva of Mexican patients with caries in mixed and permanent dentition.

SUBJECTS AND METHODS:

This was a comparative cross-sectional study. mRNA was isolated from 200 μL of saliva following the RNA III Tissue Fresh-frozen protocol of the MagNA Pure LC Instrument 2.0 (Roche Diagnostics GmbH, Nederland BV) and the FcαR, FcαμR and FcγRIIB were quantified through TaqMan Assays.

RESULTS:

One hundred individuals, 50 with mixed dentition and 50 with permanent dentition, were included in the study. Statistically, it was found a significant difference (p = 0.025) in the IgG (FcγRIIB) expression between the studied groups.

CONCLUSION:

Although we confirmed the existence of FcαR, FcγRIIB and FcαμR gene expression in saliva, only a significant difference in the expression of FcγRIIB between the mixed dentition and permanent dentition was found.

A comparison of salivary IgA in children with Down syndrome and their family members

The aim of this study was to compare total IgA in the whole saliva of children with Down syndrome with levels in sibling and parent groups. IgA measurements were presented as the concentration in saliva (μg/ml) and also adjusted for salivary flow rate (SFR; μg/min). Twenty children with Down syndrome, ten siblings and twenty parents were recruited. Stimulated whole saliva was collected from the participants and SFR calculated. The measurement of salivary IgA (sIgA) was carried out using an indirect competitive Enzyme-Linked Immunosorbent Assay. The difference in the mean SFR between children with Down syndrome, parents and siblings were not statistically significant. The mean salivary concentration of IgA was higher in children with Down syndrome (95.1 μg/ml) compared with siblings (48.3 μg/ml; p=0.004). When adjusted for SFR children with Down syndrome had mean sIgA levels of 98.8 μg/min and the siblings 48.6 μg/min (p=0.008). The children with Down syndrome had sIgA levels similar to those of the parents (92.5 μg/ml; 93.2 μg/min). There was a positive correlation between age and sIgA concentration in the siblings (p=0.008) but not for children with Down syndrome (p=0.363). This suggests that under similar environmental influences, the levels of sIgA in children with Down syndrome are higher than in the siblings, from a very young age.

Breastmilk-Saliva Interactions Boost Innate Immunity by Regulating the Oral Microbiome in Early Infancy

INTRODUCTION

Xanthine oxidase (XO) is distributed in mammals largely in the liver and small intestine, but also is highly active in milk where it generates hydrogen peroxide (H2O2). Adult human saliva is low in hypoxanthine and xanthine, the substrates of XO, and high in the lactoperoxidase substrate thiocyanate, but saliva of neonates has not been examined.

RESULTS

Median concentrations of hypoxanthine and xanthine in neonatal saliva (27 and 19 μM respectively) were ten-fold higher than in adult saliva (2.1 and 1.7 μM). Fresh breastmilk contained 27.3 ± 12.2 μM H2O2 but mixing baby saliva with breastmilk additionally generated >40 μM H2O2, sufficient to inhibit growth of the opportunistic pathogens Staphylococcus aureus and Salmonella spp. Oral peroxidase activity in neonatal saliva was variable but low (median 7 U/L, range 2-449) compared to adults (620 U/L, 48-1348), while peroxidase substrate thiocyanate in neonatal saliva was surprisingly high. Baby but not adult saliva also contained nucleosides and nucleobases that encouraged growth of the commensal bacteria Lactobacillus, but inhibited opportunistic pathogens; these nucleosides/bases may also promote growth of immature gut cells. Transition from neonatal to adult saliva pattern occurred during the weaning period. A survey of saliva from domesticated mammals revealed wide variation in nucleoside/base patterns.

DISCUSSION AND CONCLUSION

During breast-feeding, baby saliva reacts with breastmilk to produce reactive oxygen species, while simultaneously providing growth-promoting nucleotide precursors. Milk thus plays more than a simply nutritional role in mammals, interacting with infant saliva to produce a potent combination of stimulatory and inhibitory metabolites that regulate early oral-and hence gut-microbiota. Consequently, milk-saliva mixing appears to represent unique biochemical synergism which boosts early innate immunity.

Bifidobacterium and enteral feeding in preterm infants: cluster-randomized trial

BACKGROUND

This study evaluated the benefit of Bifidobacterium bifidum OLB6378 (B. bifidum) in very low-birthweight (VLBW) infants (birthweight <1500 g) for the acceleration of enteral feeding.

METHODS

A cluster-randomized, double-blind, placebo-controlled trial was conducted in 19 hospitals, divided into two groups: the B group (n = 10 hospitals; B. bifidum given to infants within 48 h of birth) and the P group (n = 9 hospitals; infants received a placebo). The primary outcome was establishment of enteral feeding after birth, defined as the postnatal day at which enteral feeding exceeded 100 mL/(kg/day). Secondary outcomes were defined as incidence of morbidity and somatic growth before discharge.

RESULTS

Overall, 283 VLBW infants were enrolled in the study: B group, n = 153; and P group, n = 130. Enteral feeding was established within 21 days after birth in 233 infants, of whom 119 received B. bifidum and 114 received placebo until their bodyweight reached 2000 g. Enteral feeding was established significantly earlier in the B group, at 11.0 ± 3.6 days versus 12.1 ± 3.8 days in P group (P < 0.05). Infant growth during the stay in the neonatal intensive care unit was not different between groups, but the incidence of late-onset sepsis among all enrolled infants was significantly lower in the B group (3.9%, 6/153) than in the P group (10.0%, 13/130; P < 0.05). No differences were observed in the incidence of other adverse outcomes including mortality.

CONCLUSIONS

B. bifidum in VLBW infants accelerated the establishment of enteral feeding after birth without increasing the incidence of adverse effects.

Salivary antibody response to streptococci in preterm and fullterm children: a prospective study

OBJECTIVES

Secretory immunoglobulins present in mucosa surfaces represent the first line of defense of the adaptive immune system against infectious challenges. Preterm (PT) neonates' humoral immunity is diminished compared to full-term (FT) newborns. The identification of important antigens (Ags) of virulence of oral species may help in the investigation of the mechanisms of antigenic stimulation and the development of the mucosal immune response. In the present study, we measured saliva levels of immunoglobulins A (IgA) and M (IgM) and characterized the specificity of IgA against Ags of several streptococcal species found early in life.

METHODS

This was a prospective observational study. Salivary IgA (sIgA) antibody responses to bacterial species that are prototypes of pioneer (Streptococcus mitis, S. sanguinis, S. gordonii) and pathogenic (Streptococcus mutans) microorganisms of the oral cavity were studied in FT and PT children in two visits: at birth (T0) and at 3 months of age (T3). Salivas from 123 infants (72 FT and 51 PT) were collected during the first 10h after birth (T0) and again at 3 months of age (T3). Salivary levels of IgA and IgM antibodies were analysed by enzyme-linked immunosorbent assay (ELISA). A subgroup of 26 FT and 24 PT children were compared with respect to patterns of antibody specificities against different streptococci Ags using Western blot assays.

RESULTS

No significant differences (P>0.05) in salivary levels of IgA and IgM between FT and PT babies were found at birth. At T3, mean sIgA values were similar between groups and sIgM levels were significantly higher in PT than FT (P<0.05). Western blot assays identified positive IgA response to streptococci in the majority of children, especially in the FT group. There were some differences between groups in relation to the frequency of children with positive response to Ags and intensity of IgA response. In general, oral streptococci Ags were more frequently detected and bands were more intense in FT than in PT, especially in T3. Prospective analysis of patterns of sIgA against Ags of different streptococcal species revealed an increase in complexity of the sIgA antibody response from the first day of birth (T0) to T3 in PT and FT.

CONCLUSION

The patterns of sIgA response to streptococci Ags appear to be influenced by the gestational age, which might reflect the level of immunological maturity of the mucosal immune system.

Bacterial colonization, enamel defects and dental caries in 4-6-year-old mono- and dizygotic twins

BACKGROUND

Knowledge of the genetic and environmental influences in caries aetiology has relevance for preventive dentistry.

AIMS

This classical twin study compared concordance of mutans streptococci (MS) and lactobacilli (LB) colonization, enamel defects, and caries in a cohort of 4-6-year-old mono- (MZ) and dizygotic (DZ) twin pairs.

DESIGN

The twins were examined for prevalence and concordance of enamel opacities and hypoplasia, oral counts of MS and LB, and dental caries. Bacterial counts were assessed using a commercial microbiological kit.

RESULTS

Thirty-four MZ and 50 DZ twins (mean gestational age 35.0 ± 2.4 weeks, and birthweight 2.4 ± 0.6 kg) were examined. There were no statistically significant differences between MZ and DZ twins in the prevalence of MS, LB, and enamel hypoplasia. Concordance rates for MS and LB presence and prevalence of enamel defects within MZ and DZ twin pairs were not significantly different. There were more children with caries in DZ compared with MZ twins (18% vs 3%, P = 0.0029), most likely due to increased daily frequency of sugar consumption and less toothbrushing.

CONCLUSIONS

Concordance data from MZ and DZ twins did not demonstrate any statistically significant difference in susceptibility for enamel defects and colonization of MS and LB.

Collection and determination of nucleotide metabolites in neonatal and adult saliva by high performance liquid chromatography with tandem mass spectrometry

Saliva contains a number of biochemical components which may be useful for diagnosis/monitoring of metabolic disorders, and as markers of cancer or heart disease. Saliva collection is attractive as a non-invasive sampling method for infants and elderly patients. We present a method suitable for saliva collection from neonates. We have applied this technique for the determination of salivary nucleotide metabolites. Saliva was collected from 10 healthy neonates using washed cotton swabs, and directly from 10 adults. Two methods for saliva extraction from oral swabs were evaluated. The analytes were then separated using high performance liquid chromatography (HPLC) with tandem mass spectrometry (MS/MS). The limits of detection for 14 purine/pyrimidine metabolites were variable, ranging from 0.01 to 1.0μM. Recovery of hydrophobic purine/pyrimidine metabolites from cotton tips was consistently high using water/acetonitrile extraction (92.7-111%) compared with water extraction alone. The concentrations of these metabolites were significantly higher in neonatal saliva than in adults. Preliminary ranges for nucleotide metabolites in neonatal and adult saliva are reported. Hypoxanthine and xanthine were grossly raised in neonates (49.3±25.4; 30.9±19.5μM respectively) compared to adults (4.3±3.3; 4.6±4.5μM); nucleosides were also markedly raised in neonates. This study focuses on three essential details: contamination of oral swabs during manufacturing and how to overcome this; weighing swabs to accurately measure small saliva volumes; and methods for extracting saliva metabolites of interest from cotton swabs. A method is described for determining nucleotide metabolites using HPLC with photodiode array or MS/MS. The advantages of utilising saliva are highlighted. Nucleotide metabolites were not simply in equilibrium with plasma, but may be actively secreted into saliva, and this process is more active in neonates than adults.

Salivary IgA antibody responses to Streptococcus mitis and Streptococcus mutans in preterm and fullterm newborn children

OBJECTIVES

The intensities and specificities of salivary IgA antibody responses to antigens of Streptococcus mutans, the main pathogen of dental caries, may influence colonization by these organisms during the first 1.5 year of life. Thus, the ontogeny of salivary IgA responses to oral colonizers continues to warrant investigation, especially with regard to the influence of birth conditions, e.g. prematurity, on the ability of children to efficiently respond to oral microorganisms. In this study, we characterised the salivary antibody responses to two bacterial species which are prototypes of pioneer and pathogenic microorganisms of the oral cavity (Streptococcus mitis and Streptococcus mutans, respectively) in fullterm (FT) and preterm (PT) newborn children.

METHODS

Salivas from 123 infants (70 FT and 53 PT) were collected during the first 10h after birth and levels of IgA and IgM antibodies and the presence of S. mutans and S. mitis were analysed respectively by ELISA and by chequerboard DNA-DNA hybridization. Two subgroups of 24 FT and 24 PT children were compared with respect to patterns of antibody specificities against S. mutans and S. mitis antigens, using Western blot assays. Cross-adsorption of 10 infant's saliva was tested to S. mitis, S. mutans and Enterococcus faecalis antigens.

RESULTS

Salivary levels of IgA at birth were 2.5-fold higher in FT than in PT children (Mann-Whitney; P<0.05). Salivary IgA antibodies reactive with several antigens of S. mitis and S. mutans were detected at birth in children with undetectable levels of those bacteria. Adsorption of infant saliva with cells of S. mutans produced a reduction of antibodies recognizing S. mitis antigens in half of the neonates. The diversity and intensity of IgA responses were lower in PT compared to FT children, although those differences were not significant.

CONCLUSION

These data provide evidence that children have salivary IgA antibodies shortly after birth, which might influence the establishment of the oral microbiota, and that the levels of salivary antibody might be related to prematurity.

Alterações orais em crianças prematuras e de baixo peso ao nascer: a importância da relação entre pediatras e odontopediatras

OBJETIVO: Apresentar uma revisão de literatura sobre as alterações orais em crianças prematuras e de baixo peso ao nascer. FONTES DE DADOS: Foram selecionados artigos em inglês e português, desde 1976 até 2009, pesquisados no PubMed, Lilacs e na Bibliografia Brasileira de Odontologia (BBO), além de livros e consensos nacionais e internacionais. As palavras-chave utilizadas foram: "prematuro", "recém-nascido de baixo peso", "cárie dentária", "hipoplasia do esmalte dentário", "manifestações bucais e "dentição primária". Selecionaram-se artigos avaliando incidência, prevalência e etiologia das alterações orais, além de revisões de literatura e relatos de casos clínicos. SÍNTESE DOS DADOS: As alterações orais mais comuns em crianças prematuras e de baixo peso ao nascer são os defeitos no esmalte dentário (hipoplasias e hipocalcificações), a predisposição ao desenvolvimento de lesões de cárie dentária, as alterações na cronologia de erupção dentária e as alterações no palato com consequente aparecimento de maloclusão. Outras alterações também são relatadas, como diferenças nas dimensões das coroas dentárias e na espessura e porosidade do esmalte dentário. A interação entre pediatras e odontopediatras é fundamental no manejo dessas crianças. CONCLUSÕES: O conhecimento das alterações orais em crianças pré-termo e de baixo peso ao nascer por parte dos pediatras e odontopediatras favorece a atuação multidisciplinar com o objetivo de educar, prevenir e atenuar as possíveis mudanças físicas e dentárias nessas crianças.

Developmental profiles of mucosal immunity in pre-school children

This study investigated the effect of attending pre-school on mucosal immunity. Children 3.5 to 5 years of age who attended pre-school were observed for a 10 month period. Demographic information was collected on previous childcare experiences, the home environment and clinical information relating to the child and the family. A daily illness log was kept for each child. A multivariate longitudinal analysis of the relation between immunoglobulins in saliva and age, gender, childcare experience, pre-school exposure, number of siblings, environmental tobacco smoke (ETS), atopy and hospitalisation was conducted. There was a positive association of higher IgA levels with the winter season and with children being older than 4 years (P < .001), having attended childcare prior to commencing pre-school (P < .05), and having been exposed to ETS at home (P < .05). Lower IgA levels were associated with being atopic (P < .05). Higher IgG levels were associated with exposure to ETS (P < .001), while lower levels were associated to having atopy. Higher IgM levels were associated with previous childcare experience (P < .01) whilst having been hospitalised was associated with having low salivary IgM levels (P < .01). Lagged analyses demonstrated that immunological parameters were affected by the number of respiratory infections in the preceding 2 months.

Oral Streptococcus species in pre-term and full-term children - a longitudinal study

BACKGROUND

Despite high clinical significance, the microbiology of the dental biofilm in young children remains poorly understood.

AIM

The aim of this longitudinal study was to investigate five Streptoccocus species commonly found in the oral biofilm of children, namely Streptococcus mutans, Streptococcus sobrinus, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus salivarius to determine their relative numbers in caries-free pre-term children, and age-matched full-term controls.

DESIGN

Plaque and saliva samples were obtained from 15 pre-term children and 15 age-matched controls at ages 3, 6, 12, 18, and 24 months. A quantitative real-time PCR technique was used to determine the numbers of five species of Streptococcus using probes and primers specific for each bacterial species.

RESULTS

All species of Streptococcus generally increased from ages 3 to 24 months. The relative ratios of the bacteria remained fairly constant at all ages studied (P > 0.1). There were no significant differences in numbers of all Streptococcus species between pre-term children and full-term controls at all the ages investigated between.

CONCLUSION

The results show that the relative numbers of S. mutans, S. sobrinus, S. mitis, S. sanguinis, and S. salivarius remain relatively constant from 3 to 24 months of age in caries-free pre- and full-term children.

Development of immunoglobulin A in infancy and childhood

Serum and salivary concentrations of immunoglobulin A1 (IgA1) and IgA2 were studied in 105 Icelandic children aged 0-12 years. Serum concentrations of both IgA1 and IgA2 increased slightly (P < 0.001) during childhood. The salivary IgA1/IgA2 ratio tended to decrease during the same period; this trend is less apparent when omitting the youngest children. The salivary IgA1 and IgA2 output could be high, even in children with low levels of serum IgA. Only polymeric IgA was found in whole saliva. Interestingly, in serum, most IgA1 and IgA2 were polymeric during infancy. The proportion of polymeric IgA decreased, when the concentration of IgA increased. The polymeric form of IgA might provide the infant with better protection against invading microorganisms by activation of the innate immune mechanisms.