The relationship between eosinophilia and bronchopulmonary dysplasia in premature infants at less than 34 weeks' gestation

Postnatal longitudinal analysis of serum Nitric oxide and eosinophil counts in extremely preterm infants

BACKGROUND

Nitric oxide (NO) may be related to the pathogenesis of several morbidities in extremely preterm infants, including late-onset adrenal insufficiency. However, eosinophilia is observed under pathological conditions with adrenal insufficiency. Therefore, this study explored postnatal changes in NO levels and eosinophil counts in extremely preterm infants with and without morbidities.

METHODS

Nineteen extremely preterm infants with a median gestational age of 27.0 weeks and median birth weight of 888 g were enrolled in this study. Serum levels of nitrogen oxides (NOx) and peripheral blood eosinophil counts were measured at birth and every 2 weeks thereafter. Morbidities of the study group were diagnosed using a single criterion.

RESULTS

Serum NOx levels (mean ± standard deviation) were 22.5 ± 14.9 μmol/L, 51.2 ± 23.7 μmol/L, 42.4 ± 15.2 μmol/L, and 33.8 ± 9.4 μmol/L at birth and 2, 4, and 6 weeks of age, respectively. The serum NOx level at 2 weeks of age was significantly higher than that at birth and 6 weeks of age. Eosinophil counts, which increase with adrenal insufficiency, were measured simultaneously and were 145 ± 199/μL, 613 ± 625/μL, 466 ± 375/μL, and 292 ± 228/μL at birth and 2, 4, and 6 weeks of age, respectively. These values showed that the eosinophil count was significantly higher at 2 weeks of age than at birth and 6 weeks of age. The serum NOx level of infants without chorioamnionitis was significantly increased at 4 weeks of age, and the eosinophil count of infants with necrotizing enterocolitis was significantly increased at 2 weeks of age. No correlation with the NOx level or eosinophil count was observed in infants with late-onset circulatory collapse.

CONCLUSION

The postnatal serum NOx level and eosinophil count were significantly correlated with each other and peaked at 2 weeks of age.

Invasive mechanical ventilation and biomarkers as predictors of bronchopulmonary dysplasia in preterm infants

OBJECTIVES

To evaluate the impact of invasive mechanical ventilation associated with two serum inflammatory cytokines and clinical indicators, on the second day of life, as predictors of bronchopulmonary dysplasia in very low birth weight preterm infants. It was hypothesized that the use of invasive mechanical ventilation in the first hours of life is associated with biomarkers that may predict the chances of preterm infants to develop bronchopulmonary dysplasia.

METHODS

Prospective cohort of 40 preterm infants with gestational age <34 weeks and birth weight <1500 g. The following were analyzed: clinical variables; types of ventilator support used (there is a higher occurrence of bronchopulmonary dysplasia when oxygen supplementation is performed by long periods of invasive mechanical ventilation); hospitalization time; quantification of two cytokines (granulocyte and macrophage colony stimulating factor [GM-CSF] and eotaxin) in blood between 36 and 48 h of life. The preterm infants were divided in two groups: with and without bronchopulmonary dysplasia.

RESULTS

The GM-CSF levels presented a significantly higher value in the bronchopulmonary dysplasia group (p = 0.002), while eotaxin presented higher levels in the group without bronchopulmonary dysplasia (p = 0.02). The use of continuous invasive mechanical ventilation was associated with increased ratios between GM-CSF and eotaxin (100% sensitivity and 80% specificity; receiver operating characteristic area = 0.9013, CI = 0.7791-1.024, p < 0.0001).

CONCLUSIONS

The duration of invasive mechanical ventilation performed in the first 48 h of life in the very low birth weight infants is a significant clinical predictor of bronchopulmonary dysplasia. The use of continuous invasive mechanical ventilation was associated with increased ratios between GM-CSF and eotaxin, suggesting increased lung injury and consequent progression of the disease.

Impact and Clinical Implications of Prematurity on Adaptive Immune Development

Purpose of Review

Detail normal adaptive immune maturation during fetal and neonatal life and review the clinical implications of arrested immune development.

Recent Findings

Advancements in the field of immunology have enabled investigations of the adaptive immunity starting during fetal life. New insights have drawn important distinctions between the neonatal and adult immune systems. The presence of diverse immunologic responses in the perinatal period suggests the importance of in utero immune development. Disruption of immune maturation due to premature birth may have significant implications for clinical pathology.

Summary

Establishing protective adaptive immunity during the perinatal period is critical for effective immune responses later in life. Preterm infants are susceptible to aberrant immune system maturation and inflammatory immune responses have been associated with the development of necrotizing enterocolitis (NEC) and bronchopulmonary dysplasia (BPD). Improving our understanding of how immune responses contribute to the pathogenesis of NEC and BPD may offer new opportunities for future treatment and prevention of these diseases.

Increased serum Th2 chemokine levels are associated with bronchopulmonary dysplasia in premature infants

Bronchopulmonary dysplasia (BPD) is one of the most common chronic inflammatory lung disease of premature infants, with serious short- and long-term consequences. Early identification of premature infants at risk of BPD is critical to preventing the pathogenesis of disease. Thus, in the present study, we recruited 126 premature infants, collected peripheral blood samples at different time points during early life, and measured the concentration of Th1 (MCP-1, IP-10, and MIG) and Th2 (eotaxin-1, eotaxin-2, and MCP-4) chemokines in serum. We found serum eotaxin-2 levels were significantly higher in the BPD group than in the non-BPD group on day 1 [1662 pg/ml vs. 1221 pg/ml, P < 0.05], day 7 [1533 pg/ml vs. 1089 pg/ml, P < 0.05], and day 14 [1246 pg/ml vs. 704 pg/ml, P < 0.05] after birth, and serum MCP-4 levels were also significantly higher in the BPD group than in the non-BPD group on day 1 [186 pg/ml vs. 128 pg/ml, P < 0.05], day 7 [199 pg/ml vs. 101 pg/ml, P < 0.05], and day 14 [238 pg/ml vs. 106 pg/ml, P < 0.05] of life.Conclusions: Increased levels of Th2 chemokines, eotaxin-2, and MCP-4, are associated with BPD in premature infants. What is Known: • The pathogenesis of BPD is multifactorial and it is difficult to predict and prevent. • Previous studies have demonstrated that inflammation plays a major role in the pathogenesis of BPD. What is New: • Increased Th2 chemokines, eotaxin-2 and MCP-4, were associated with BPD in premature infants. • Abnormal Th1/Th2 response in early life maybe associated with the subsequent development of BPD, which provide a new insight to understand the pathogenesis of the disease.

Serum eotaxin-1 is increased in extremely-low-birth-weight infants with bronchopulmonary dysplasia or death

BACKGROUND

Early systemic inflammation in extremely-low-birth-weight (ELBW) infants is associated with an increased risk of bronchopulmonary dysplasia (BPD). Our objective was to identify circulating biomarkers and develop prediction models for BPD/death soon after birth.

METHODS

Blood samples from postnatal day 1 were analyzed for C-reactive protein (CRP) by enzyme-linked immunosorbent assay and for 39 cytokines/chemokines by a multiplex assay in 152 ELBW infants. The primary outcome was physiologic BPD or death by 36 wk. CRP, cytokines, and clinical variables available at ≤24 h were used for forward stepwise regression and Classification and Regression Tree (CART) analysis to identify predictors of BPD/death.

RESULTS

Overall, 24% developed BPD and 35% died or developed BPD. Regression analysis identified birth weight and eotaxin (CCL11) as the two most significant variables. CART identified FiO2 at 24 h (11% BPD/death if FiO2 ≤28%, 49% if >28%) and eotaxin in infants with FiO2 > 28% (29% BPD/death if eotaxin was ≤84 pg/ml; 65% if >84) as variables most associated with outcome.

CONCLUSION

Eotaxin measured on the day of birth is useful for identifying ELBW infants at risk of BPD/death. Further investigation is required to determine if eotaxin is involved in lung injury and pathogenesis of BPD.