Differential anti-viral response to respiratory syncytial virus A in preterm and term infants

BACKGROUND

Preterm infants are more likely to experience severe respiratory syncytial virus (RSV) disease compared to term infants. The reasons for this are multi-factorial, however their immature immune system is believed to be a major contributing factor.

METHODS

We collected cord blood from 25 preterm (gestational age 30.4-34.1 weeks) and 25 term infants (gestation age 37-40 weeks) and compared the response of cord blood mononuclear cells (CBMCs) to RSVA and RSVB stimulation using neutralising assays, high-dimensional flow cytometry, multiplex cytokine assays and RNA-sequencing.

FINDINGS

We found that preterm and term infants had similar maternally derived neutralising antibody titres to RSVA and RSVB. Preterm infants had significantly higher myeloid dendritic cells (mDC) RSV infection compared to term infants. Differential gene expression analysis of RSVA stimulated CBMCs revealed enrichment of genes involved in cytokine production and immune regulatory pathways involving IL-10, IL-36γ, CXCL1, CXCL2, SOCS1 and SOCS3 in term infants, while differentially expressed genes (DEGs) in preterm infants were related to cell cycle (CDK1, TTK, ESCO2, KNL1, CDC25A, MAD2L1) without associated expression of immune response genes. Furthermore, enriched genes in term infants were highly correlated suggesting an increased co-ordination of their immune response to RSVA. When comparing DEGs in preterm and term infants following RSVB stimulation, no differences in immune response genes were identified.

INTERPRETATION

Overall, our data suggests that preterm infants have a more restricted immunological response to RSVA compared with term infants. While further studies are required, these findings may help to explain why preterm infants are more susceptible to severe RSV disease and identify potential therapeutic targets to protect these vulnerable infants.

FUNDING

Murdoch Children's Research Institute Infection and Immunity theme grant.

Association of maternal prenatal copper concentration with gestational duration and preterm birth: a multicountry meta-analysis

BACKGROUND

Copper (Cu), an essential trace mineral regulating multiple actions of inflammation and oxidative stress, has been implicated in risk for preterm birth (PTB).

OBJECTIVES

This study aimed to determine the association of maternal Cu concentration during pregnancy with PTB risk and gestational duration in a large multicohort study including diverse populations.

METHODS

Maternal plasma or serum samples of 10,449 singleton live births were obtained from 18 geographically diverse study cohorts. Maternal Cu concentrations were determined using inductively coupled plasma mass spectrometry. The associations of maternal Cu with PTB and gestational duration were analyzed using logistic and linear regressions for each cohort. The estimates were then combined using meta-analysis. Associations between maternal Cu and acute-phase reactants (APRs) and infection status were analyzed in 1239 samples from the Malawi cohort.

RESULTS

The maternal prenatal Cu concentration in our study samples followed normal distribution with mean of 1.92 μg/mL and standard deviation of 0.43 μg/mL, and Cu concentrations increased with gestational age up to 20 wk. The random-effect meta-analysis across 18 cohorts revealed that 1 μg/mL increase in maternal Cu concentration was associated with higher risk of PTB with odds ratio of 1.30 (95% confidence interval [CI]: 1.08, 1.57) and shorter gestational duration of 1.64 d (95% CI: 0.56, 2.73). In the Malawi cohort, higher maternal Cu concentration, concentrations of multiple APRs, and infections (malaria and HIV) were correlated and associated with greater risk of PTB and shorter gestational duration.

CONCLUSIONS

Our study supports robust negative association between maternal Cu and gestational duration and positive association with risk for PTB. Cu concentration was strongly correlated with APRs and infection status suggesting its potential role in inflammation, a pathway implicated in the mechanisms of PTB. Therefore, maternal Cu could be used as potential marker of integrated inflammatory pathways during pregnancy and risk for PTB.

TLR Responses in Preterm and Term Infant Cord Blood Mononuclear Cells

Preterm infants are more susceptible to severe bacterial and viral infectious diseases than their full-term counterparts. A major contributor to this increased susceptibility may be due to differences in their ability to respond to pathogens. While studies have demonstrated altered bacterial Toll-like receptor (TLR) responses, there is limited data on viral TLR responses in preterm infants. In this study, cord blood mononuclear cells (CBMCs) from 10 moderately preterm (30.4-34.1 wGA), 10 term (37-39.5 wGA) infants, and 5 adults were stimulated with TLR2 (lipoteichoic acid), TLR3 (poly I:C), TLR4 (lipopolysaccharide), TLR7/8 (R848), and TLR9 (CpG-ODN 2216) agonists. Following stimulation, the cellular response was measured by intracellular flow cytometry to detect cell-specific NF-κB (as a marker of the inflammatory response), and multiplex assays were used to measure the cytokine response. This study found that preterm and term infants exhibit very similar baseline TLR expression. In response to both bacterial and viral TLR agonists comparing cell-specific NF-κB activation, preterm infants exhibited increased monocyte activation following LTA stimulation; however, no other differences were observed. Similarly, no difference in cytokine response was observed following stimulation with TLRs. However, a stronger correlation between NF-κB activation and cytokine responses was observed in term infants following poly I:C and R848 stimulation compared to preterm infants. In contrast, despite similar TLR expression, adults produced higher levels of IFN-α following R848 stimulation compared to preterm and term infants. These findings suggest preterm and term infants have a similar capacity to respond to both bacterial and viral TLR agonists. As preterm infants are more likely to develop severe infections, further research is required to determine the immunological factors that may be driving this and develop better interventions for this highly vulnerable group.

Effects of higher protein formula with improved fat blend on growth, feeding tolerance and nutritional biomarkers in preterm infants: A double-blind, randomized, controlled clinical trial

BACKGROUND

Preterm formulas containing greater protein:energy ratio are beneficial for non-breastfed infants, since protein is critical for promoting catch-up growth and synthesis of lean body mass. Additionally, formulas containing enriched sn-2 palmitate (sn-2) and reduced medium chain triglycerides (MCTs) may support better feeding tolerance and nutrient utilization.

METHODS

The objective of this randomized, controlled, double-blinded clinical trial is to evaluate growth, feeding tolerance and nutritional biomarkers of preterm infants with birth weight ≤2000g and gestational age ≤33wks from one neonatal unit in Vietnam receiving experimental formula (EF, n = 80) containing higher protein level of 3.4 g/100 kcal and improved fat blend with enriched sn-2 and modified level of MCTs or isocaloric control formula (CF, n = 80) containing protein level of 2.9 g/100 kcal and standard fat blend. The differences in weight gain (g/d; primary endpoint) from day 1 (D1) of full enteral feeding (FEF) until D21 between groups was evaluated for non-inferiority (margin = -2.5  g/d) and superiority (margin = 0  g/d).

RESULTS

Mean weight gain was 3.09  g/d greater in EF than CF; the lower limit of 95% CI (0.31  g/d) exceeded both non-inferiority and superiority margins. There was no significant difference in length-for-age and head circumference-for-age z-score. By D79, the mean change in weight-for-age z-scores from D1 in EF group (+0.76 SDs) surpassed the criteria for catch-up growth (+0.67 SDs). Infants in the EF group (vs. CF) tended to have softer stools (EF = 3.2 ± 0.59 vs. CF = 3.4 ± 0.58; P = 0.07) based on 5-point scale (1 = watery, 5 = hard). Difference in blood urea nitrogen and biomarkers for bone mineral status (i.e., plasma phosphorus, alkaline phosphatase and urinary calcium/phosphorus ratio) between EF and CF on FEF Day 21 reached statistical significance (P < 0.05) but all mean values stayed within normal clinical ranges for both groups.

CONCLUSION

Preterm formula with greater protein:energy ratio and new fat blend is safe, nutritionally suitable, well-tolerated, and improves catch-up weight gain of preterm infants. Clinical trial registry identifier is NCT03055052 (ClinicalTrials.gov).

Clinical consequences of gestational diabetes mellitus and maternal obesity as defined by asian BMI thresholds in Viet Nam: a prospective, hospital-based, cohort study

BACKGROUND

Gestational Diabetes Mellitus (GDM) is common in South East Asia, occurring at relatively lean Body Mass Index (BMI). Outside pregnancy, cardiometabolic risks increase at lower BMI in Asian populations, justifying Asian-specific thresholds for overweight and obesity. We aimed to explore the effects of GDM and obesity on perinatal outcomes using a WHO expert consultation-recommended Asian-specific definition of obesity.

METHODS

This is a secondary analysis of a prospective, hospital-based, cohort study in Ho Chi Minh City. Participants were recruited from antenatal clinics between 19^+ 0-22^+ 6 weeks gestation and followed until delivery. GDM screening occurred between 24 and 28 weeks using WHO criteria. Obesity was defined as BMI ≥ 27.5 kg/m², based on weight and height at recruitment. We assessed associations between GDM (singly, and in combination with obesity) and perinatal outcomes. Participants were categorised into four groups: no GDM/non-obese (reference group), GDM/non-obese, no GDM/obese and GDM/obese. Outcomes included primary caesarean section, hypertensive disorders of pregnancy (HDP), large-for-gestational-age (LGA), birth weight, preterm birth, and composite adverse neonatal outcome. Logistic and linear regressions were performed with adjustment for differences in baseline characteristics.

RESULTS

Among 4,970 participants, 908 (18%) developed GDM. Compared to women without GDM, GDM increased risks for preterm birth (OR: 1.40, 95% CI: 1.09-1.78), higher birthweight (birthweight z-score 0.16 versus 0.09, p = 0.027), and LGA (OR 1.14, 0.89-1.46). GDM without obesity was associated with an increased risk of preterm birth (OR 1.35, 1.04-1.74). Obese women without GDM were more likely to deliver by caesarean section and have an LGA baby (1.80, 1.33-2.44 and 2.75, 1.88-4.03). The highest risks were observed amongst women with both GDM and obesity: caesarean Sect. (2.43, 1.49-3.96), LGA (3.36, 1.94-5.80) and preterm birth (2.42, 1.32-4.44).

CONCLUSIONS

GDM was associated with an increased risk of preterm birth and larger newborn size. Using an Asian-specific definition of obesity, we demonstrate obese women with GDM are at the highest risk of adverse outcomes. Using a BMI threshold in pregnancy of 27.5 kg/m² (between 19 and 22 weeks gestation) for Asian women can identify women who will benefit from intensified diabetes, nutritional, and obstetric care. This has relevance for obstetric service delivery within Asia, and other health systems providing pregnancy care for Asian expatriate women.

Immune Profiling of Cord Blood From Preterm and Term Infants Reveals Distinct Differences in Pro-Inflammatory Responses

Background

Preterm infants are highly vulnerable to infectious disease. While many factors are likely to contribute to this enhanced susceptibility, the immature nature of the preterm immune system is postulated as one key factor.

Methods

In our study, we used high-dimensional flow cytometry and cytokine assays to characterise the immune profiles in 25 preterm (range: 30.4-34.1 weeks gestational age) and 25 term infant (range: 37-40 weeks gestational age) cord blood samples.

Results

We found that preterm infants exhibit reduced frequencies of monocytes, CD56^bright NK cells, CD8+ T-cells, γδ T-cells and an increased frequency of intermediate monocytes, CD4+ T-cells, central memory CD4+ and CD8+ T-cells, Tregs and transitional B-cells compared to term infants. Pro-inflammatory cytokines IL-1β, IL-6 and IL-17A were lower in preterm infants in addition to chemokines IL-8, eotaxin, MIP-1α and MIP-1β. However, IL-15 and MCP-1 were higher in preterm infants.

Conclusion

Overall, we identify key differences in pro-inflammatory immune profiles between preterm and term infants. These findings may help to explain why preterm infants are more susceptible to infectious disease during early life and facilitate the development of targeted interventions to protect this highly vulnerable group.

Recurrent BRCA1 Mutation, but no BRCA2 Mutation, in Vietnamese Patients with Ovarian Carcinoma Detected with Next Generation Sequencing

Background:

Identification of germline and somatic BRCA1/2 mutations in ovarian cancer is important for genetic counseling and treatment decision making with poly ADP ribose polymerase inhibitors. Unfortunately, data on the frequency of BRCA1/2 mutations in Vietnamese patients are scare.

Methods:

We aim to explore the occurrence of BRCA1/2 mutations in 101 Vietnamese patients with ovarian cancer including serous (n = 58), endometrioid (n = 14), mucinous (n = 24), and clear cell (n = 5) carcinomas. BRCA1/2 mutations were detected from formalin-fixed parafin-embedded tumor samples using the Oncomine^TM BRCA Research Assay on Personal Genome Machine Platform with Ion Reporter Software for sequencing data analysis. The presence of pathogenic mutations was confirmed by Sanger sequencing.

Results:

We found no BRCA2 mutation in the entire cohort. Four types of pathogenic mutations in BRCA1 (Ser454Ter, Gln541Ter, Arg1751Ter, and Gln1779AsnfsTer14) were detected in 8 unrelated patients (7.9%) belonging to serous and endometrioid carcinoma groups. Except for the c.1360_1361delAG (Ser454Ter) mutation in BRCA1 exon 11 that was somatic, the other mutations in exons 11, 20, and 22 were germline. Interestingly, the recurrent Arg1751Ter mutation in BRCA1 exon 20 appeared in 4 patients, suggesting that this is a founder mutation in Vietnamese patients.

Conclusion:

Mutational analysis of tumor tissue using next generation sequencing allowed the detection of both germline and somatic BRCA1/2 mutations.

Clinical pregnancy following GnRH agonist administration in the luteal phase of fresh or frozen assisted reproductive technology (ART) cycles: Systematic review and meta-analysis

Objective(s)

To study if the GnRH agonist administration in luteal phase improves clinical pregnancy rate of fresh and frozen embryo transfer. Also, this meta-analysis compares the treatment effect of luteal GnRH agonist administration between long agonist and antagonist protocols of fresh cycles, and between two types of treatment: fresh and frozen embryo transfers.

Study design

Systematic review and meta-analysis (registration number CRD42017059152)

Results

For the overall 20 studies (5497 patients), clinical pregnancy rate significantly increased in group of GnRH agonist administration compared to control group (RR 1.24, 95% CI 1.14–1.34, p < 0.0001). Regarding the treatment effect of luteal GnRH agonist administration between long agonist and antagonist protocol fresh cycles, no significant difference was observed (RR = 1.28, 95% CI 0.98–1.67, p = 0.07). Also, in comparison between fresh and frozen embryo transfer, similar effect of GnRH agonist administration was found (RR = 0.93, 95% CI 0.74–1.16, p = 0.49).

Conclusion(s)

There is evidence that GnRH agonist administration in luteal phase improve clinical pregnancy rate in both fresh and frozen cycles. Within fresh cycles, no significant difference of clinical pregnancy rate is found between two protocols. In frozen cycles, the effect of GnRH agonist administration in enhancing clinical pregnancy rate is similar to fresh cycles.