Newborns and young infants suffer increased infectious morbidity and mortality as compared to older children and adults. Morbidity and mortality due to infection are highest during the first weeks of life, decreasing over several years. Furthermore, most vaccines are not administered around birth, but over the first few years of life. A more complete understanding of the ontogeny of the immune system over the first years of life is thus urgently needed. Here, we applied the most comprehensive analysis focused on the innate immune response following TLR stimulation over the first 2 years of life in the largest such longitudinal cohort studied to-date (35 subjects). We found that innate TLR responses (i) known to support Th17 adaptive immune responses (IL-23, IL-6) peaked around birth and declined over the following 2 years only to increase again by adulthood; (ii) potentially supporting antiviral defense (IFN-α) reached adult level function by 1 year of age; (iii) known to support Th1 type immunity (IL-12p70, IFN-γ) slowly rose from a low at birth but remained far below adult responses even at 2 years of age; (iv) inducing IL-10 production steadily declined from a high around birth to adult levels by 1 or 2 years of age, and; (v) leading to production of TNF-α or IL-1β varied by stimuli. Our data contradict the notion of a linear progression from an ‘immature’ neonatal to a ‘mature’ adult pattern, but instead indicate the existence of qualitative and quantitative age-specific changes in innate immune reactivity in response to TLR stimulation.

Ocular mal-development results in heterogeneous and frequently visually disabling phenotypes that include coloboma and microphthalmia. Due to the contribution of bone morphogenetic proteins to such processes, the function of the paralogue Growth Differentiation Factor 3 was investigated. Multiple mis-sense variants were identified in patients with ocular and/or skeletal (Klippel-Feil) anomalies including one individual with heterozygous alterations in GDF3 and GDF6. These variants were characterized, individually and in combination, through integrated biochemical and zebrafish model organism analyses, demonstrating appreciable effects with western blot analyses, luciferase based reporter assays and antisense morpholino inhibition. Notably, inhibition of the zebrafish co-orthologue of GDF3 accurately recapitulates patient phenotypes. By demonstrating the pleiotropic effects of GDF3 mutation, these results extend the contribution of perturbed BMP signaling to human disease and potentially implicate multi-allelic inheritance of BMP variants in developmental disorders.

Respiratory diseases are the most frequent chronic illnesses in babies and children. Although a vigorous innate immune system is critical for maintaining lung health, a balanced response is essential to minimize damaging inflammation. We investigated the functional and clinical impact of human genetic variants in the promoter of NFKBIA, which encodes IκBα, the major negative regulator of NF-κB. In this study, we quantified the functional impact of NFKBIA promoter polymorphisms (rs3138053, rs2233406, and rs2233409) on promoter-driven protein expression, allele-specific and total NFKBIA mRNA expression, IκBα protein expression, and TLR responsiveness; mapped innate immune regulatory networks active during respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia; and genotyped and analyzed independent cohorts of children with respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Genetic variants in the promoter of NFKBIA influenced NFKBIA gene expression, IκBα protein expression, and TLR-mediated inflammatory responses. Using a systems biology approach, we demonstrated that NFKBIA/IκBα is a central hub in transcriptional responses of prevalent childhood lung diseases, including respiratory syncytial virus infection, asthma, and bronchopulmonary dysplasia. Finally, by examining independent pediatric lung disease cohorts, we established that this immunologically relevant genetic variation in the promoter of NFKBIA is associated with differential susceptibility to severe bronchiolitis following infection with respiratory syncytial virus, airway hyperresponsiveness, and severe bronchopulmonary dysplasia. These data highlight the importance of negative innate immune regulators, such as NFKBIA, in pediatric lung disease and begin to unravel common aspects in the genetic predisposition to bronchopulmonary dysplasia, bronchiolitis, and childhood asthma.

A single-step approach for the synthesis of polyphosphazenes containing sulfonic acid functionalities is developed. Polyphosphazene "sulfonation" is conducted via the direct replacement of chlorine atoms of the macromolecular precursor, poly(dichlorophosphazene), PDCP with a sulfonic acid containing nucleophileshydroxybenzenesulfonic acid. The method makes use of "noncovalent" protection of the sulfonic acid functionality with a hydrophobic ammonium ion, such as the dimethyldipalmitylammonium ion, which then can be easily removed after the completion of the reaction. 1 H, 31 P, and 13 C NMR and size-exclusion HPLC studies revealed no macromolecular byproducts or noticeable degradation of the polyphosphazene backbone under the conditions of the synthesis. Both sulfonated polyphosphazene homopolymers and mixed substituent copolymers containing 4-ethylphenoxy side groups were synthesized and characterized.

Significant variability in cytokine and chemokine expression after Toll-like receptor (TLR) stimulation has been observed between individuals. In this study, we determined the immunophenotypic variation in a cohort of 152 neonates associated with specific single-nucleotide polymorphisms (SNPs). We identified 23 SNPs in 12 genes of the innate immune system to be significantly associated with differential cytokine and chemokine production. SNPs in three gene families, namely STAT, IRF and SYK, accounted for most associations. These gene families are important signaling components of the innate anti-viral response. A potentially damaging non-synonymous SNP in the TLR3 gene (rs3775291) associated with significant differences in expression of interferon-γ after stimulation with the synthetic TLR3 ligand, poly (I:C). Additionally, a general increase in cytokine production was observed in subjects of Asian descent. This observation could be associated with differences in SNP genotype distribution between racial groups in our cohort. Taken together, our data suggest that particular aspects of the newborn innate response to TLR stimulation are closely associated with genetic variation. These findings provide the basis for detailed molecular dissection of cause-effect relationships between genotype and immune responses, and may account for inter-individual differences in response to vaccination and risk for infection and autoimmune disease.

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The failure of anti-sepsis treatments in the past is most likely related to wrong timing of the drugs due to missing reliable biomarkers to assess the condition of the patients. The authors believe that the development of anti-sepsis drugs using time-critical ('vertical') and continuous ('horizontal') approaches may provide the answer for future novel therapeutics.

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