Development of serum IgA and IgM levels in breast-fed and formula-fed infants during the first week of life

Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is an inflammatory disease affecting premature infants. Intestinal microbial composition may play a key role in determining which infants are predisposed to NEC and when infants are at highest risk of developing NEC. It is unclear how to optimize antibiotic therapy in preterm infants to prevent NEC and how to optimize antibiotic regimens to treat neonates with NEC. This article discusses risk factors for NEC, how dysbiosis in preterm infants plays a role in the pathogenesis of NEC, and how probiotic and antibiotic therapy may be used to prevent and/or treat NEC and its sequelae.

Interaction between IgA and gut microbiota and its role in controlling metabolic syndrome

Immunoglobulin A (IgA) is the most abundant immunoglobulin isotype secreted into the mucosal tissues, mainly intestinal mucus. Humans can produce several grams of IgA every day, accounting for three quarters of the body's total immunoglobulin content. IgA, together with mucus and antimicrobial peptides, forms the first line of defence for intestinal epithelial cells, protecting them from a significant number of intestinal antigens. IgA also plays a principal role in controlling the gut microbiota (GM), and disruption in IgA can result in dysbiosis, such as the enrichment of Proteobacteria, which are generally bound by IgA. Proteobacteria overexpansion is also usually seen in obesity and colitis. Consistent with this, IgA dysfunction frequently results in metabolic syndrome (MetS), including conditions such as obesity, adiposity, insulin resistance, and inflammation. In contrast, enhanced IgA function can improve, and even prevent, MetS. Interactions among IgA, GM, and metabolism provide a promising avenue to combat MetS.

Human breast milk oligosaccharides attenuate necrotizing enterocolitis in rats by suppressing mast cell accumulation, DPPI activity and TLR4 expression in ileum tissue, and regulating mitochondrial damage of Caco-2 cells

Necrotizing enterocolitis (NEC), a devastating infant disease characterized by severe intestinal necrosis, its pathogenesis is poorly understood, but appears to be multifactorial and highly associated with immaturity of gastrointestinal tract and immature innate-immune system. Breast-milk is effective strategy to protect infants against NEC. This study is using a NEC rat model to investigate the pathological mechanism of NEC involved intestinal-damages, and the therapeutic mechanism of sialylated human milk oligosaccharides (SHMOs) on NEC rats; also using cell model to investigate the effects of SHMOs on colon-epithelial cells (Caco-2) in-vitro. Extraction and characterization of SHMOs from breast milk, establishment of a NEC rat model, histopathological analysis and mast cell accounting of the terminal ileum were taken; The levels of DPPI, TLR4, IL-6, TNF-α, MMP-2/9 and glutathione were measured using various methods. Caco-2 cells were pre-treated with SHMOs and cultured with LPS, histamine, chymase or DPPI, cell viabilities and mitochondrial membrane potential were examined; flow cytometry was used to detect cell cycle. The accumulation of mast cells was found in the ileum of NEC rats, but prohibited by SHMOs treatment; the increased levels of TLR4, DPPI, IL-6, TNF-α, MMP-2/9 in NEC ileum were suppressed by SHMOs in-vivo. SHMOs prevented Caco-2 cells from LPS, histamine, chymase induced damages by surviving cell viability, regulating G0/G1 and S phase in cell cycles, and increasing mitochondrial membrane potential. These findings provide a new insight into the pharmacological mechanism of SHMOs treatment for NEC and suggest that SHMOs needs well attention for therapeutic aims.

Dysregulated Mucosal Immunity and Associated Pathogeneses in Preterm Neonates

Many functions of the immune system are impaired in neonates, allowing vulnerability to serious bacterial, viral and fungal infections which would otherwise not be pathogenic to mature individuals. This vulnerability is exacerbated in compromised newborns such as premature neonates and those who have undergone surgery or who require care in an intensive care unit. Higher susceptibility of preterm neonates to infections is associated with delayed immune system maturation, with deficiencies present in both the innate and adaptive immune components. Here, we review recent insights into early life immunity, and highlight features associated with compromised newborns, given the challenges of studying neonatal immunity in compromised neonates due to the transient nature of this period of life, and logistical and ethical obstacles posed by undertaking studies newborns and infants. Finally, we highlight how the unique immunological characteristics of the premature host play key roles in the pathogenesis of diseases that are unique to this population, including necrotizing enterocolitis and the associated sequalae of lung and brain injury.

Early breastfeeding is associated with low risk of postpartum depression in Taiwanese women

Breastfeeding during the first week postpartum is recognised as essential, affecting the mother's mental health. The human milk from early breastfeeding also protects against infections via the secretory IgA antibodies and plays an important role in the newborn's development. At a Baby-Friendly Hospital, early breastfeeding was promoted to increase the benefits for the newborn, but few focussed on the mother's health. The association between breastfeeding and postpartum depression (PPD) has not been fully addressed. This study aimed to investigate the relationship between breastfeeding and postpartum depression (PPD) and it included 333 Taiwanese pregnant women. Women who had a higher score of Edinburgh Postnatal Depression Scale (EPDS) were significant older (age ≥ 35, p < .037), had a caesarean section delivery (p < .001), and a higher score of Brief Symptom Rating Scale-5 (p < .001). Higher scores on EPDS were significantly associated with lower rates of breastfeeding, which reflected cessation of breastfeeding as an important risk factor for PPD (Odds ratio: 2.159, CI: 1.220-3.821, p = .008). Other risk factors included caesarean section delivery (Odds ratio: 2.814, CI: 1.617-4.899, p < .001) and age ≥35 years (Odds ratio: 1.821, CI: 1.057-3.137, p = .031).IMPACT STATEMENTWhat is already known on this subject: Breastfeeding during the first week postpartum is recognised as essential, affecting the mother's mental health. The human milk from early breastfeeding also protects against infections via the secretory IgA antibodies and plays an important role in the newborn's development. The detail association between breastfeeding and postpartum depression has not yet been fully addressed.What the results of this study add: Higher scores on EPDS were significantly associated with lower rates of breastfeeding, which reflected cessation of breastfeeding as an important risk factor for PPD (Odds ratio: 2.159, CI: 1.220-3.821, p = .008). Other risk factors included caesarean section delivery (Odds ratio: 2.814, CI: 1.617-4.899, p < .001) and age ≥35 years (Odds ratio: 1.821, CI: 1.057-3.137, p = .031).What the implications are of these findings for clinical practice and/or further research? The early breastfeeding was significantly associated with postpartum depression. Other risk factors included caesarean section delivery and age ≥35 years.

Immunoglobulin A Dysgammaglobulinemia Is Associated with Pediatric-Onset Obsessive-Compulsive Disorder

Background: Inflammation and immune dysregulation have been implicated in the pathogenesis of pediatric-onset obsessive-compulsive disorder (OCD) and tic disorders such as Tourette syndrome (TS). Though few replicated studies have identified markers of immune dysfunction in this population, preliminary studies suggest that serum immunoglobulin A (IgA) concentrations may be abnormal in these children with these disorders. Methods: This observational retrospective cohort study, conducted using electronic health records (EHRs), identified 206 children with pediatric-onset OCD and 1024 adults diagnosed with OCD who also had testing for serum levels of IgA. IgA deficiency and serum IgA levels in pediatric OCD were compared with IgA levels from children diagnosed with autism spectrum disorders (ASD; n = 524), tic disorders (n = 157), attention-deficit/hyperactivity disorder (ADHD; n = 534), anxiety disorders (n = 1206), and celiac disease, a condition associated with IgA deficiency (n = 624). Results: Compared with ASD and anxiety disorder cohorts, the pediatric OCD cohort displayed a significantly higher likelihood of IgA deficiency (OR = 1.93; 95% CI = 1.18-3.16, and OR = 1.98; 95% CI = 1.28-3.06, respectively), though no difference was observed between pediatric OCD and TS cohorts. Furthermore, the pediatric OCD cohort displayed similar rates of IgA deficiency and serum IgA levels when compared with the celiac disease cohort. The pediatric OCD cohort also displayed the highest percentage of IgA deficiency (15%,) when compared with TS (14%), celiac disease (14%), ADHD (13%), ASD (8%), and anxiety disorder (8%) cohorts. When segregated by sex, boys with OCD displayed a significantly higher likelihood of IgA deficiency when compared with all comparison cohorts except for celiac disease and tic disorders; no significant difference in IgA deficiency was observed between female cohorts. Pediatric OCD subjects also displayed significantly lower adjusted serum IgA levels than the ASD and anxiety disorder cohorts. Adults with OCD were also significantly less likely than children with OCD to display IgA deficiency (OR = 2.71; 95% CI = 1.71-4.28). When compared with children with celiac disease, no significant difference in IgA levels or rates of IgA deficiency were observed in the pediatric OCD cohort. Conclusions: We provide further evidence of IgA abnormalities in pediatric-onset OCD. These results require further investigation to determine if these abnormalities impact the clinical course of OCD in children.

Pathogenesis of NEC: Role of the innate and adaptive immune response

Necrotizing enterocolitis (NEC) is a devastating disease in premature infants with high case fatality and significant morbidity among survivors. Immaturity of intestinal host defenses predisposes the premature infant gut to injury. An abnormal bacterial colonization pattern with a deficiency of commensal bacteria may lead to a further breakdown of these host defense mechanisms, predisposing the infant to NEC. Here, we review the role of the innate and adaptive immune system in the pathophysiology of NEC.

Immunoglobulin Concentrations in Plasma and Saliva During the Neonatal Period

BACKGROUND

Screening for infectious diseases in newborns using immunoglobulin (Ig)A-, IgM-, and IgE-specific antibodies is expensive and impractical. To determine if total levels of these Igs can be used for screening purposes, thus simplifying the process, their basic levels in the 1(st) month of extrauterine life need to be determined. Additionally, the ability to simplify screening by using saliva also needs to be determined. The aim of this study was to determine IgA, IgM, and IgE concentrations in plasma and saliva in newborns, correlation between the samples, and relationship between Ig levels and newborn age.

METHODS

We enrolled 53 apparently healthy newborns, paired samples of plasma and saliva were collected, and total IgA, IgM, and IgE concentrations determined by capture enzyme-linked immunosorbent assay. The correlation between plasma and saliva values was calculated by Spearman's rank correlation coefficient and the IgA, IgM, and IgE distributions were analyzed by the Shapiro-Wilk test. We also determined the level of each Ig concentration according to age.

RESULTS

IgA and IgM levels in plasma and IgA levels in saliva increased significantly during 1(st) month of life, especially in the 2(nd) week and 3(rd) week, with a good correlation of IgA between plasma and saliva. IgE levels in both plasma and saliva and IgM levels in saliva were very low or absent.

CONCLUSION

These results suggest that Igs in saliva could be good biomarkers for newborn screening programs during the 1(st) week of life. This study established reference values for Igs according to age in the neonatal period.

Limited expression of APRIL and its receptors prior to intestinal IgA plasma cell development during human infancy

The absence of immunoglobulin A (IgA) in the intestinal tract renders young infants highly susceptible to enteric infections. However, mediators of initial IgA induction in this population are undefined. We determined the temporal acquisition of plasma cells by isotype and expression of T cell-independent (TI) and -dependent (TD) IgA class switch factors in the human intestinal tract during early infancy. We found that IgA plasma cells were largely absent in the infant intestine until after 1 month of age, approaching adult densities later in infancy than both IgM and IgG. The restricted development of IgA plasma cells in the first month was accompanied by reduced expression of the TI factor a proliferation-inducing ligand (APRIL) and its receptors TACI (transmembrane activator and calcium-modulator and cyclophilin ligand interactor) and B cell maturation antigen (BCMA) within isolated lymphoid follicles (ILFs). Moreover, both APRIL and BCMA expression strongly correlated with increasing IgA plasma cell densities over time. Conversely, TD mediators (CD40 ligand (CD40L) and CD40) were expressed within ILFs before 1 month and were not associated with IgA plasma cell generation. In addition, preterm infants had lower densities of IgA plasma cells and reduced APRIL expression compared with full-term infants. Thus, blunted TI responses may contribute to the delayed induction of intestinal IgA during early human infancy.