Primary immunodeficiency testing in a Massachusetts tertiary care NICU: persistent challenges in the extremely premature population.

BACKGROUND: Prematurity presents a diagnostic challenge in interpreting primary immunodeficiency (PID) testing. METHODS: We retrospectively reviewed the charts of all infants in our level IV referral neonatal intensive care unit (NICU) in Massachusetts, with immunologic testing performed from 2006 to 2018. RESULTS: The overall rate of PID testing was enriched in our population, with 1% of admitted patients having extended immunologic testing. The addition of TREC (T cell receptor excision circle) newborn screening in Massachusetts in 2009 increased the proportion of infants tested for PID in our NICU by 3-fold (1.21% post-newborn screening (NBS) vs. 0.46% pre-NBS). A majority of the term and late preterm (≥34 weeks) infants (31 of 41, 76%), as well as very premature (29-33 weeks) infants (12 of 17, 71%), who had immune testing, had a genetic diagnosis associated with secondary immunodeficiency or a PID. Most infants who were born extremely premature (EP, <29 weeks) (25 of 29, 86%) had no identifiable cause of immunodeficiency besides prematurity, despite a mean postmenstrual age of 40.1 weeks at the time of testing. CONCLUSIONS: Persistent immune derangements were present within a subgroup of the EP population through term postmenstrual age. EP infants with significant infectious history and abnormal immune testing at term-corrected age should be considered for genetic testing. IMPACT: The role of immunologic testing in the premature population is unclear, we therefore reviewed the records of all infants in our NICU who had immunologic testing, to rule out immunodeficiency, done from 2006 to 2018. The addition of newborn screening for SCID in 2009 doubled the number of infants who had immune investigations. The extremely premature cohort included many infants with persistent immune derangements through term-corrected gestational age, suggesting a persistent effect of prematurity on immune development and potential function. We propose that former premature infants with clinical evidence of immunodeficiency and sustained immune abnormalities by term-corrected age undergo genetic testing for immunodeficiency.

Innate lymphoid cells are reduced in pregnant HIV positive women and are associated with preterm birth.

Preterm birth is the leading cause of neonatal and child mortality worldwide. Globally, 1.4 million pregnant women are estimated to be living with HIV/AIDS, the majority of whom live in sub-Saharan Africa. Maternal HIV infection and antiretroviral treatment (ART) have been associated with increased rates of preterm birth, but the underlying mechanisms remain unknown. Acute HIV infection is associated with a rapid depletion of all three subsets of innate lymphoid cells (ILCs), ILC1s, ILC2s and ILC3s, which is not reversed by ART. ILCs have been found at the maternal-fetal interface and we therefore investigated the potential association between maternal HIV infection, peripheral ILC frequencies and preterm birth. In our study of pregnant South African women with accurately dated pregnancies, we show that maternal HIV infection is associated with reduced levels of all three ILC subsets. Preterm birth was also associated with lower levels of all three ILC subsets in early pregnancy. ILC frequencies were lowest in HIV positive women who experienced preterm birth. Moreover, ILC levels were reduced in pregnancies resulting in spontaneous onset of preterm labour and in extreme preterm birth (< 28 weeks gestation). Our findings suggest that reduced ILC frequencies may be a link between maternal HIV infection and preterm birth. In addition, ILC frequencies in early pregnancy may serve as predictive biomarkers for women who are at risk of delivering preterm.

Oropharyngeal Colostrum Positively Modulates the Inflammatory Response in Preterm Neonates.

During the first days of life, premature infants have physiological difficulties swallowing, thereby missing out on the benefits of breastfeeding. The aim of this study is to assess the effects of oropharyngeal mother's milk administration in the inflammatory signaling of extremely premature infants. Neonates (n = 100) (<32 week's gestation and/or <1500 g) were divided into two groups: mother's milk group (n = 48), receiving 0.2 mL of oropharyngeal mother's milk every 4 h for the first 15 days of life, and a control group (n = 52), not receiving oropharyngeal mother's milk. Serum concentrations of interleukin (IL) IL-6, IL-8, IL-10, IL-1ra, tumor necrosis factor alpha (TNF-α), and interferón gamma (IFN-γ) were assessed at 1, 3, 15, and 30 days of postnatal life. Maternal and neonatal outcomes were collected. The rate of common neonatal morbidities in both groups was similar. The mother's milk group achieved full enteral feeding earlier, and showed a decrease in Il-6 on days 15 and 30, in IL-8 on day 30, and in TNF-α and INF-γ on day 15, as well as an increase in IL-1ra on days 3 and 15 and in IL-10 on day 30. Oropharyngeal mother's milk administration for 15 days decreases the pro-inflammatory state of preterm neonates and provides full enteral nutrition earlier, which could have a positive influence on the development of the immune system and inflammatory response, thereby positively influencing other developmental outcomes.

Postnatal probiotics and allergic disease in very preterm infants: Sub-study to the ProPrems randomized trial.

BACKGROUND: Probiotic supplementation to mothers and/or their term-born infants has been suggested to prevent allergic disease, in particular eczema; however, no studies have investigated probiotics for prevention of allergic diseases in very preterm infants. We evaluated the effect of a postnatal probiotic combination on development of allergic diseases in very preterm infants. METHODS: This sub-study was an a priori secondary outcome of the ProPrems multi-center, double-blind, placebo-controlled randomized trial (ANZCTR:12607000144415). ProPrems randomized 1099 very preterm infants to receive a probiotic combination or placebo from soon after birth until discharge from hospital or term corrected age (CA), whichever was earlier. Allergic disease (eczema, atopic eczema, food allergy, wheeze, atopic sensitization) was assessed in a subgroup of ProPrems infants (n = 281) as close to 12 months CA as possible by questionnaire, clinical examination, and skin prick tests to common allergens. RESULTS: There was no difference in eczema incidence between the probiotic and placebo groups (35[30%] of 118 infants vs 37[27%] of 137 infants, respectively, absolute difference 2.65%, 95% CI -8.45 to 13.75). Similarly, the incidence of atopic eczema (6[5%] of 118 vs 3[2%] of 137), food allergy (4[3%] of 124 vs 2[1%] of 154), wheeze (39[31%] of 127 vs 45[29%] of 154), and atopic sensitization (14[13%] of 106 vs 13[11%] of 123) were similar between the probiotic and placebo groups. CONCLUSION: This study found no effect of postnatal administration of a probiotic combination on the incidence of allergic diseases or atopic sensitization in the first 2 years of life in children born very preterm. Evidence that probiotics are effective for prevention of allergic disease in premature infants remains lacking; adequately powered randomized controlled trials evaluating probiotic supplementation for allergy prevention in very preterm infants are needed.

Late-onset group B streptococcus infections and severe bronchopulmonary dysplasia in an extremely preterm born infant.

This case report is about a boy born extremely preterm at gestational age of 24 weeks, with extremely low birth weight, developing severe bronchopulmonary dysplasia and in need of mechanical ventilation for 155 days. He also had five recurrent infections with group B streptococcus (GBS) within 4 months from birth, and his respiratory condition clearly deteriorated with every GBS infection. It was difficult to wean him from mechanical ventilation. Finally he was extubated when he was 7 months old and kept out of mechanical ventilation after receiving high-dose methylprednisolone, given according to international recommendations. After GBS was cultured for the fifth time, he received oral rifampicin along with intravenous penicillin and after this treatment, GBS did not occur again. At the age of 22 months, the boy no longer needed any respiratory support and he was about 6 months late in his neurological development.

Exosomal microRNA predicts and protects against severe bronchopulmonary dysplasia in extremely premature infants.

Premature infants are at high risk for developing bronchopulmonary dysplasia (BPD), characterized by chronic inflammation and inhibition of lung development, which we have recently identified as being modulated by microRNAs (miRNAs) and alterations in the airway microbiome. Exosomes and exosomal miRNAs may regulate cell differentiation and tissue and organ development. We discovered that tracheal aspirates from infants with severe BPD had increased numbers of, but smaller, exosomes compared with term controls. Similarly, bronchoalveolar lavage fluid from hyperoxia-exposed mice (an animal model of BPD) and supernatants from hyperoxia-exposed human bronchial epithelial cells (in vitro model of BPD) had increased exosomes compared with air controls. Next, in a prospective cohort study of tracheal aspirates obtained at birth from extremely preterm infants, utilizing independent discovery and validation cohorts, we identified unbiased exosomal miRNA signatures predictive of severe BPD. The strongest signal of reduced miR-876-3p in BPD-susceptible compared with BPD-resistant infants was confirmed in the animal model and in vitro models of BPD. In addition, based on our recent discovery of increased Proteobacteria in the airway microbiome being associated with BPD, we developed potentially novel in vivo and in vitro models for BPD combining Proteobacterial LPS and hyperoxia exposure. Addition of LPS led to a larger reduction in exosomal miR 876-3p in both hyperoxia and normoxia compared with hyperoxia alone, thus indicating a potential mechanism by which alterations in microbiota can suppress miR 876-3p. Gain of function of miR 876-3p improved the alveolar architecture in the in vivo BPD model, demonstrating a causal link between miR 876-3p and BPD. In summary, we provide evidence for the strong predictive biomarker potential of miR 876-3p in severe BPD. We also provide insights on the pathogenesis of neonatal lung disease, as modulated by hyperoxia and microbial product-induced changes in exosomal miRNA 876-3p, which could be targeted for future therapeutic development.

Antenatal and Neonatal Antecedents of Executive Dysfunctions in Extremely Preterm Children.

To find out why children born extremely preterm are at heightened risk of executive dysfunctions, the authors assessed 716 children who were 10 years old born extremely preterm whose IQ was ≥ 70. A working memory dysfunction (n = 169), an inhibition dysfunction (n = 360), a switching dysfunction (355), and all 3 (executive dysfunction; n = 107) were defined on the basis of Z-scores ≤ -1 on the Differential Ability Scales-II Working Memory composite, and/or on the NEPSY-II Inhibition-Inhibition and Inhibition-Switching subtests. All risk profiles include an indicator of socioeconomic disadvantage. The risk profile of each of the 3 individual dysfunctions includes an indicator of the newborn's immaturity, and the risk profiles of the inhibition dysfunction and switching dysfunction also include an indicator of inflammation. Only the switching dysfunction was associated with fetal growth restriction. The risk factors for executive dysfunction can be subsumed under the 4 themes of socioeconomic disadvantage, immaturity/vulnerability, inflammation, and fetal growth restriction.

Altered Intracellular ATP Production by Activated CD4+ T-Cells in Very Preterm Infants.

Background. The neonatal immune system is not fully developed at birth; newborns have adequate lymphocytes counts but these cells lack function. Objective. To assess the activity of T-cells and the influence of the main perinatal factors in very preterm infants (birth weight < 1500 g). Design. Blood samples from 59 preterm infants (21/59 were dizygotic twins) were collected at birth and at 30 days of life to measure CD4+ T-cell activity using the ImmuKnow™ assay. Fifteen healthy adults were included as a control group. Results. CD4+ T-cell activity was lower in VLBW infants compared with adults (p < 0.001). Twins showed lower immune activity compared to singletons (p = 0.005). Infants born vaginally showed higher CD4+ T-cell activity compared to those born by C-section (p = 0.031); infants born after prolonged Premature Rupture of Membranes (pPROM) showed higher CD4+ T-cell activity at birth (p = 0.002) compared to infants born without pPROM. Low CD4+ T-cell activity at birth is associated with necrotizing enterocolitis (NEC) in the first week of life (p = 0.049). Conclusions. Preterm infants show a lack in CD4+ T-cell activity at birth. Perinatal factors such as intrauterine inflammation, mode of delivery, and zygosity can influence the adaptive immune activation capacity at birth and can contribute to exposing these infants to serious complications such as NEC.

Rhinovirus-induced airway cytokines and respiratory morbidity in severely premature children.

BACKGROUND: Rhinovirus (RV) has been linked to the pathogenesis of asthma. Prematurity is a risk factor for severe RV infection in early life, but is unknown if RV elicits enhanced pro-asthmatic airway cytokine responses in premature infants. This study investigated whether young children born severely premature (<32 wks gestation) exhibit airway secretion of Th2 and Th17 cytokines during natural RV infections and whether RV-induced Th2-Th17 responses are linked to more respiratory morbidity in premature children during the first 2 yrs of life. METHODS: We measured Th2 and Th17 nasal airway cytokines in a retrospective cohort of young children aged 0-2 yrs with PCR-confirmed RV infection or non-detectable virus. Protein levels of IL-4, IL-13, TSLP, and IL-17 were determined with multiplex immunoassays. Demographic and clinical variables were obtained by electronic medical record (EMR) review. RESULTS: The study comprised 214 children born full term (n = 108), preterm (n = 44) or severely premature (n = 62). Natural RV infection in severely premature children was associated with elevated airway secretion of Th2 (IL-4 and IL-13) and Th17 (IL-17) cytokines, particularly in subjects with history of bronchopulmonary dysplasia. Severely premature children with high RV-induced airway IL-4 had recurrent respiratory hospitalizations (median 3.65 hosp/yr; IQR 2.8-4.8) and were more likely to have at least one pediatric intensive care unit admission during the first 2 yrs of life (OR 8.72; 95% CI 1.3-58.7; p = 0.02). CONCLUSIONS: Severely premature children have increased airway secretion of Th2 and Th17 cytokines during RV infections, which is associated with more respiratory morbidity in the first 2 yrs of life.

RAGE controls leukocyte adhesion in preterm and term infants.

BACKGROUND: Insufficient leukocyte recruitment may be one reason for the high incidence of life-threatening infections in preterm infants. Since the receptor of advanced glycation end products (RAGE) is a known leukocyte adhesion molecule and highly expressed during early development, we asked whether RAGE plays a role for leukocyte recruitment in preterm and term infants. METHODS: Leukocyte adhesion was analyzed in dynamic flow chamber experiments using isolated leukocytes of cord blood from extremely premature (<30 weeks of gestation), moderately premature (30-35 weeks of gestation) and mature neonates (>35 weeks of gestation) and compared to the results of adults. For fluorescent microscopy leukocytes were labeled with rhodamine 6G. In the respective age groups we also measured the plasma concentration of soluble RAGE (sRAGE) by ELISA and Mac-1 and LFA-1 expression on neutrophils by flow cytometry. RESULTS: The adhesive functions of fetal leukocytes significantly increase with gestational age. In all age groups, leukocyte adhesion was crucially dependent on RAGE. In particular, RAGE was equally effective to mediate leukocyte adhesion when compared to ICAM-1. The plasma levels of sRAGE were high in extremely premature infants and decreased with increasing gestational age. In contrast, expression of ß2-Integrins Mac-1 and LFA-1 which are known ligands for RAGE and ICAM-1 did not change during fetal development. CONCLUSION: We conclude that RAGE is a crucial leukocyte adhesion molecule in both preterm and term infants.

Hierarchical maturation of innate immune defences in very preterm neonates.

BACKGROUND: Preterm neonates are highly vulnerable to infection. OBJECTIVES: To investigate the developmental contribution of prematurity, chorioamnionitis and antenatal corticosteroids (ANS) on the maturation of neonatal microbial pathogen recognition responses. METHODS: Using standardized protocols, we assayed multiple inflammatory cytokine responses (IL-1ß, IL-6, TNF-α and IL-12/23p40) to three prototypic Toll-like receptor (TLR) agonists, i.e. TLR4 (lipopolysaccharide), TLR5 (flagellin) and TLR7/8 (R848), and to the non-TLR retinoic acid-inducible gene I (RIG-I)-like receptor agonist, in cord blood mononuclear cells from neonates born before 33 weeks of gestation and at term. RESULTS: TLR responses develop asynchronously in preterm neonates, whereby responses to TLR7/8 were more mature and were followed by the development of TLR4 responses, which were also heterogeneous. Responses to TLR5 were weakest and most immature. Maturity in TLR responses was not influenced by sex. Overall, we detected no significant contribution of ANS and chorioamnionitis to the developmental attenuation of either TLR or RIG-I responses. CONCLUSIONS: The maturation of anti-microbial responses in neonates born early in gestation follows an asynchronous developmental hierarchy independently of an exposure to chorioamnionitis and ANS. Our data provide an immunological basis for the predominance of specific microbial infections in this age group.

Low monocyte HLA-DR expression as an indicator of immunodepression in very low birth weight infants.

BACKGROUND: As a protective response to an inflammatory stimulus, the antigen-presenting molecules (human leukocyte antigen-DR (HLA-DR)) on monocytes are downregulated. If severe, the response may lead to immunodepression or immunoparalysis, associated with an increased rate of morbidity and mortality in adults. In very low birth weight (VLBW) infants, birth and intensive care present major immunological challenges. METHODS: We measured monocyte HLA-DR expression by flow cytometry and determined 13 plasma cytokines in 56 VLBW infants (gestational age (GA): 23.7-31.8 wk) and 25 controls (GA: 34.1-41.4 wk). RESULTS: HLA-DR expression decreased postnatally both in VLBW and in control infants. In VLBW infants, GA and respiratory distress syndrome (RDS) both showed associations with HLA-DR nadir on day 3, when 45% of them met the criteria of immunodepression. HLA-DR expression was lower in those infants subsequently developing infection (74 vs. 49% (day 3) and 85 vs. 68% (day 7); both P = 0.002). Interleukin (IL)-6 on day 1 was a predictor of the HLA-DR nadir. CONCLUSION: VLBW infants are in a state of immunodepression postnatally. This immunodepression correlated with GA and was a predisposing factor for late infections. The downregulation of HLA-DR during RDS probably indicates an RDS-induced antigen load on the immune system.

Neutrophil and endothelial adhesive function during human fetal ontogeny.

Attenuation of the immune response contributes to the high rate of neonatal infections, particularly in premature infants. Whereas our knowledge of innate immune functions in mature neonates is growing, little is known about the ontogeny of neutrophil recruitment. We investigated neutrophils and ECs in the course of gestation with respect to rolling and adhesive functions. With the use of microflow chambers, we demonstrate that the neutrophil's ability to roll and adhere directly correlates with gestational age. These adhesion-related abilities are very rare in extremely premature infants (<30 weeks of gestation), which may correlate with our observation of markedly reduced expression of PSGL-1 and Mac-1 on neutrophils in preterm infants. In parallel, the capacity of HUVECs to mediate neutrophil adhesion under flow increases with gestational age. In addition, HUVECs from extremely premature infants exerting the lowest ability to recruit adult neutrophils show a diminished up-regulation of E-selectin and ICAM-1. Finally, by following neutrophil function postnatally, we show that maturation of PMN recruitment proceeds equivalently during extra- and intrauterine development. Thus, PMN recruitment and EC adhesion-related functions are ontogenetically regulated in the fetus, which might contribute significantly to the high risk of life-threatening infections in premature infants.

Vacunaciones en niños prematuros. Muchas preguntas, pocas respuestas / No disponible

Hoy en día los niños prematuros deben vacunarse a los 2 meses del nacimiento, independientemente del peso y edad gestacional, y deben de seguir el calendario como los niños a término. En un próximo futuro es muy probable que el esquema de vacunación cambie al menos para algunos grupos de prematuros. Salvo circunstancias clínicas muy especiales, la administración de las vacunas no debe retrasarse ni en el hospital ni en asistencia primaria, debiéndose continuar con las mismas vacunas con los que se iniciaron. Cuanto más pequeño es el niño más grave puede resultar la tos ferina o la infección invasiva por el Haemophilus influenzae o Streptococcus pneumoniae. Hasta que en España no se universalice el uso de la vacuna de poliomielitis inactivada (VPI) (cosa que ocurrirá pronto pese a la estulticia de algunos), en los niños ingresados en el hospital debe sustituir a la vacuna oral de virus vivos atenuados (VPO). A la luz de los datos revisados y por las complicaciones descritas no debe administrarse la vacuna pertussis de célula completa en los niños prematuros. En general, estos niños responden a las diferentes inmunizaciones con una baja reactogenicidad y con títulos frente a los diferentes antígenos más bajos que los niños a término, aunque las tasas de seroprotección superan el 90 %. Los grandes prematuros (extremadamente prematuros) responden de forma adecuada, influidos por sus condiciones clínicas particulares. En la respuesta a la formación de anticuerpos frente a la vacuna de la hepatitis B probablemente infuye más la edad posnatal que el peso. Aunque resulta un hecho controvertido, la peor respuesta parece obtenerse frente a Haemophilus, actuando como posible factor negativo el uso posnatal de corticoides. En algunos estudios se ha observado una baja respuesta frente al serotipo 3 del virus de la poliomielitis. Son excepcionales los ensayor clínicos con vacunas combinadas en prematuros, quienes por sus especiales características deberían ser uno de los primeros grupos en beneficiarse de ellas. Debe estimularse la investigación clínica en estos niños, los estudios son escasos, la metodología diversa, los resultados en ocasiones contradictorios y el número de niños bajo. Las preguntas son muchas y las respuestas muy pocas (AU)

No disponible