Trends in Survival and Incidence of Bronchopulmonary Dysplasia in Extremely Preterm Infants at 23–26 Weeks Gestation

The aim of this study was to investigate the relationship between survival and incidence of bronchopulmonary dysplasia (BPD) in extremely premature infants, and identify clinical factors responsible for this association. Medical records of 350 infants at 23–26 weeks gestation from 2000 to 2005 (period I, n = 137) and 2006 to 2010 (period II, n = 213) were retrospectively reviewed. The infants were stratified into 23–24 and 25–26 weeks gestation, and the survival, BPD incidence, and clinical characteristics were analyzed. BPD was defined as oxygen dependency at 36 weeks postmenstrual age. The overall survival rate was significantly improved in period II compared to period I (80.3% vs. 70.0%, respectively; P = 0.028), especially in infants at 23–24 weeks gestation (73.9% vs. 47.4%, respectively; P = 0.001). The BPD incidence in survivors during period II (55.0%) was significantly decreased compared to period I (67.7%; P = 0.042), especially at 25–26 weeks gestation (41.7% vs. 62.3%, respectively; P = 0.008). Significantly improved survival at 23–24 weeks gestation was associated with a higher antenatal steroid use and an improved 5-minute Apgar score. A significant decrease in BPD incidence at 25–26 weeks gestation was associated with early extubation, prolonged use of less invasive continuous positive airway pressure, and reduced supplemental oxygen. Improved perinatal and neonatal care can simultaneously lead to improved survival and decreased BPD incidence in extremely premature infants.     

Recent trends in neonatal mortality in very low birth weight Korean infants: in comparison with Japan and the USA

With regard to the outcome of intensive neonatal care, one of the most important concerns in neonatology is the mortality rate of very low birth weight infants (VLBWI; birth weight < 1,500 g) and extremely low birth weight infants (ELBWI; birth weight < 1,000 g). The present study was conducted to analyze and compare the mortality of VLBWI and ELBWI and neonatal care among Korean, Japanese, and American newborns. In Korea, the survival rates of VLBWI have increased significantly; they were 31.8% in the early 1960s, 65.8% in the early 1990s, 77.5% in 2002, 84.7% in 2007, and 85.7% in 2009. The survival rates of ELBWI have also increased; they were 8.2% in the early 1960s, 37.4% in the early 1990s, 56.1% in 2002, 67.7% in 2007, and 71.8% in 2009. The survival rates of VLBWI and ELBWI have significantly improved over the past 50 yr in Korea. However, the Korean survival rates of VLBWI and ELBWI are still lower than for similar groups in Japan and the USA. To achieve better outcomes that reach the level of these countries, the organization of perinatal care centers, nationwide neonatal perinatal research networks, and regionalization are needed in Korea.     

极低出生体重儿临床相关因素及与预后的关系

目的探讨极低出生体重儿的围产期及临床特点,分析其与预后的关系.方法分析110例极低出生体重儿(含12例超低出生体重儿)的一般情况、产科及母孕期情况、新生儿临床特点.结果胎龄小于32w者占79%,小于胎龄儿占17.3%,41%为多胎;32%有胎膜早破史,18%母亲有妊高征;36%有窒息复苏史;产科异常是胎儿早产的主要原因.呼吸暂停、低体温、高胆红素血症及低血糖是常见的并发症;多胎、围产期异常及小于胎龄儿是极低出生体重儿主要死亡原因,生于院内或转运者死亡率明显低于院外出生者(P<0.01).结论加强对高危孕妇及新生儿的监护,普及新生儿窒息复苏知识,将有助于改善极低出生体重儿的预后.     

Low birth weight,very low birth weight rates and gestational age-specific birth weight distribution of korean newborn infants

To obtain the low birth weight (LBW) rate, the very low birth weight (VLBW) rate, and gestational age (GA)-specific birth weight distribution based on a large population in Korea, we collected and analyzed the birth data of 108,486 live births with GA greater than 23 weeks for 1 yr from 1 January to 31 December 2001, from 75 hospitals and clinics located in Korea. These data included birth weight, GA, gender of the infants, delivery type, maternal age, and the presence of multiple pregnancy. The mean birth weight and GA of a crude population are 3,188 +/-518 g and 38.7+/-2.1 weeks, respectively. The LBW and the VLBW rates are 7.2% and 1.4%, respectively. The preterm birth rate (less than 37 completed weeks of gestation) is 8.4% and the very preterm birth rate (less than 32 completed weeks of gestation) is 0.7%. The mean birth weights for female infants, multiple births, and births delivered by cesarean section were lower than those for male, singletons, and births delivered vaginally. The risk of delivering LBW or VLBW infant was higher for the teenagers and the older women (aged 35 yr and more). We have also obtained the percentile distribution of GA-specific birth weight in infants over 23 weeks of gestation.     

Differential Outcomes Associated with Early Medical Complications in Premature Infants

This study evaluated the effects of several early medical complicationson the intellectual and motoric development of premature verylow birth weight (VLBW) infants. A large cohort of prematureinfants was grouped according to the following complicationsat birth: (a) intraventricular hemorrhage with respiratory distresssyndrome (IVH-RDS); (b) respiratory distress syndrome withoutintraventricular hemorrhage (RDS-no IVH); (c) bronchial-pulmonarydysplasia without IVH (BPD); (d) bronchial-pulmonary dysplasiawith IVH(BPD-IVH); and (e) hydrocephalus (HYD) secondary toIVH. These complications are frequently associated with prematurityand were hypothesized to have differential effects on laterdevelopmental outcome. Premature infants in the five diagnosticgroups received the Bayley Scales of Infant Development at 6,12, and 24 months of age. Results reveal that the IVH-RDS andRDS-no IVH infants perform similarly and show performance inthe average range for their chronological age by 24 months.In contrast, the infants in the BPD and HYD groups have generallylower scores, which remain in the delayed range throughout thefollow-up period. These results show that IVH is associatedwith poorer intellectual outcomes only when it is accompaniedby BPD or progressive hydrocephalus. In addition, longer periodsof hospitalization, which are associated with BPD, have a significantlynegative effect on later outcome. The implication of these resultsfor early intervention is discussed.     

Neonatal Morbidities Associated with Histologic Chorioamnionitis Defined Based on the Site and Extent of Inflammation in Very Low Birth Weight Infants

Conflicting results on the influences of histologic chorioamnionitis (HC) on neonatal morbidities might be partly originated from using different definition of HC. The aim of this study was to determine the relationship between HC and neonatal morbidities using definition of HC that reflects the site and extent of inflammation. This was a retrospective cohort study of 261 very low birth weight (VLBW) infants admitted at a tertiary academic center. Based on the site of inflammation, HC was categorized: any HC; amnionitis; funisitis; amnionitis+funisitis. The extent of inflammation in each site was reflected by sub-defining high grade (HG). The incidences of morbidities in infants with and without HC were compared. The bronchopulmonary dysplasia (BPD) rate was significantly higher in infants with amnionitis and the severe retinopathy of prematurity (ROP) rate was significantly higher in infants with any HC and funisitis. After adjustment for both gestational age and birth weight, the respiratory distress syndrome (RDS) rate was significantly lower in infants with all categories of HC except for HG amnionitis and HG funisitis, which are not associated with lower RDS rate. HG amnionitis was significantly associated with increased BPD rate but the association of HC with severe ROP disappeared. In conclusion, HC is significantly associated with decreased RDS and HG amnionitis with increased BPD while lacking association with other neonatal morbidities in VLBW infants. The association with HC and neonatal morbidities differs by the site and extent of chorioamnionitis.

Graphical Abstract

相似文献   

Pediatric Liver Transplantation Outcomes in Korea

Pediatric liver transplantation is the standard of care for treatment of liver failure in children. The aim of this study was to identify the characteristics of pediatric liver transplantation in centers located in Korea and determine factors that influence outcomes. This retrospective study was performed using data from between 1988 and 2010 and included all recipients 18 yr old and younger who underwent pediatric liver transplantation in Korea during that period. Our data sources were hospital medical records and the outcome measure was overall patient survival. Univariate and multivariate statistical analyses were undertaken using the Cox proportional hazards model. Five hundred and thirty-four pediatric liver transplantations were performed in 502 children. Median age and average pediatric end-stage liver disease (PELD) score were 20 months and 18 point, respectively. Biliary atresia (57.7%, 308/534) was the most common cause of liver disease. Eighty-two (15.3%) were deceased donor liver transplantations and 454 (84.7%) were living donor liver transplantations. Retransplantation was performed in 32 cases (6%). Overall, 1-, 5-, and 10-yr patient survival rates were 87.8%, 82.2%, and 78.1%, respectively. In multivariate analysis, independent significant predictors of poor patient survival were chronic rejection and retransplantation. This study presents the epidemiologic data for nearly all pediatric liver transplantation in Korea and shows that the independent prognostic factors in patient survival are chronic rejection and retransplantation.     

Differences in mortality and morbidity according to gestational ages and birth weights in infants with trisomy 18

The aim of this study was to clarify the effects of gestational age and birth weight on outcomes of the infants. Medical records of 36 infants with trisomy 18 admitted to Tokyo Women's Medical University Hospital from 1991 to 2012 were reviewed retrospectively. We compared clinical characteristics between term infants (n = 15) and preterm infants (n = 21). There were one very‐low‐birth‐weight (VLBW) term infant (5%) and 12 VLBW preterm infants (80%). Although there were no significant differences in clinical characteristics and provided management between the two groups, none of the preterm infants achieved survival to discharge. On the other hand, 6 of 21 term infants (29%) achieved survival to discharge (P < 0.05). Similar results were obtained for comparisons between the VLBW infants and non‐VLBW infants. Multiple logistic regression analysis revealed that shorter gestational age had a more negative impact than lower birth weight to survival to discharge in infants with trisomy 18. In both preterm and term groups, the infants who died before 30 days commonly died of respiratory failure or apnea. Whereas, the infants who survived more than 30 days mostly died of heart failure. © 2015 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.     

Cancer Statistics in Korea: Incidence, Mortality and Survival in 2006-2007

Cancer has been the leading cause of death in Korea. Korea is facing a very rapid change and increase in cancer incidence, which draws much attention in public health. This paper overviews the nationwide cancer statistics, including incidence, mortality, and survival rates, and their trends in Korea based on the cancer incidence data from The Korea Central Cancer Registry (KCCR) in year 2006 and 2007. In Korea, there were 153,237 cancer cases and 65,519, cancer deaths observed in 2006, and 161,920 cancer cases and 67,561 cancer deaths in 2007, respectively. The incidence rate for all cancer combined showed an annual increase of 2.8% from 1999 to 2007. Specifically, there was significant increase in the incidence of colorectal, thyroid, female breast, and prostate cancers. The number of cancer deaths has increased over the past two decades, due mostly to population aging, while the age-standardized mortality rates have decreased in both men and women since 2002. Notable improvement has been observed in the 5-yr relative survival rates for most major cancers and for all cancer combined, with the exception of pancreatic cancer. The nationwide cancer statistics in this paper will provide essential data for cancer research and evidence-based health policy in Korea.     

Cancer Statistics in Korea: Incidence, Mortality and Survival in 2005

Cancer has been the most common cause of death in Korea since 1983 and is a major public health concern. This paper overviews the nationwide cancer statistics, including incidence, mortality, and survival rates, and their trends in Korea. In 2005, 142,610 new cancer cases and 65,117 cancer deaths occurred in Korea. The incidence rate for all cancer combined increased by 2.6% annually from 1999 to 2005. Significant increases have occurred in the incidence of colorectal, thyroid, female breast, and prostate cancers. The number of cancer deaths has increased over the past two decades, due mostly to population aging, while the age-standardized mortality rates have decreased in both men and women since 2002. Notable improvement has been observed in the 5-yr relative survival rates for most major cancers and for all cancer combined, with the exception of pancreatic cancer. The nationwide cancer statistics in this paper will provide essential data for evidence-based decisions in the national cancer control program in Korea.     

Provision and availability of genomic medicine services in Level IV neonatal intensive care units

PurposeTo describe variation in genomic medicine services across level IV neonatal intensive care units (NICUs) in the United States and Canada.MethodsWe developed and distributed a novel survey to the 43 level IV NICUs belonging to the Children’s Hospitals Neonatal Consortium, requesting a single response per site from a clinician with knowledge of the provision of genomic medicine services.ResultsOverall response rate was 74% (32/43). Although chromosomal microarray and exome or genome sequencing (ES or GS) were universally available, access was restricted for 22% (7/32) and 81% (26/32) of centers, respectively. The most common restriction on ES or GS was requiring approval by a specialist (41%, 13/32). Rapid ES/GS was available in 69% of NICUs (22/32). Availability of same-day genetics consultative services was limited (41%, 13/32 sites), and pre- and post-test counseling practices varied widely.ConclusionWe observed large inter-center variation in genomic medicine services across level IV NICUs: most notably, access to rapid, comprehensive genetic testing in time frames relevant to critical care decision making was limited at many level IV Children’s Hospitals Neonatal Consortium NICUs despite a significant burden of genetic disease. Further efforts are needed to improve access to neonatal genomic medicine services.     

系统评价胎龄小于32周早产儿预防性经鼻持续气道正压通气的作用

目的评价早产儿早期应用经鼻持续气道正压通气（NCPAP）预防呼吸窘迫综合征（RDS）,减少呼吸机应用、病死率和并发症的发生。方法以（prophylactic nasal CPAP OR early nasal CPAP）AND （preterm infants OR low birth weightinfants） ,经鼻持续气道正压通气AND（早产儿OR低出生体重儿）为英中文关键词,检索PubMed、EMBASE、Cochrane临床对照试验库、维普中文科技期刊数据库、中国知网和万方数据库,检索时间均从建库至2011年12月,并辅以手工检索。应用RevMan5．0软件进行Meta分析,根据异质性结果选择相应的效应模型分析;无法进行Meta分析时采用描述性分析。结果8篇RCT文献进入分析。Meta分析结果显示：NCPAP组未能显著降低早产儿气管插管呼吸机应用率（RR=-0．09,95％CI：-0．19～0．02,P=0．09）、RDS发生率（RR=0．81,95％CI：0．59—1．1,P=0．18）和病死率（RR=0．88,95％CI：0．72～1．09,P=0．25）;NCPAP组能显著减少早产儿肺表面活性物质应用率（RR=0．72,95％CI：0．64—0．80,P〈0．00001）。NCPAP组未能显著减少气管插管呼吸机通气时间（MD=-1．91d,95％CI：-6．47～4．45d,P=0．72）及氧气应用时间（MD=-0．46d,95％CI：-6．55—5．63d,P=0．88）。NCPAP组除增加气胸的发生率外,并未明显增加支气管肺发育不良、颅内出血、早产儿视网膜病、败血症、新生儿坏死性小肠结肠炎和动脉导管未闭等并发症的发生率。结论目前的证据表明早期应用NCPAP可减少肺表面活性物质应用,但增加了气胸的发生率;未能减少早产儿呼吸机应用、RDS发生率和病死率,未增加除气胸外的其他并发症发生率。     

High Incidence of Rickets in Extremely Low Birth Weight Infants with Severe Parenteral Nutrition-Associated Cholestasis and Bronchopulmonary Dysplasia

Risk factors for rickets of prematurity have not been re-examined since introduction of high mineral formula, particularly in ELBW infants. We analyzed the incidence and the risk factors of rickets in extremely low birth weight (ELBW) infants. As a retrospective case-control study from 2004 to 2008, risk factors were analyzed in 24 patients with rickets versus 31 patients without. The frequency of rickets in ELBW infants was 24/55 (44%). Infants with rickets were diagnosed at 48.2 ± 16.1 days of age, and improved by 85.3 ± 25.3 days. By radiologic evaluation, 29% were grade 1 rickets, 58% grade 2 and 13% grade 3. In univariate analysis, infants with rickets had significantly higher incidence of patent ductus arteriosus, parenteral nutrition associated cholestasis (PNAC), severe PNAC and moderate/severe bronchopulmonary dysplasia (BPD). In multiple regression analysis, after adjustment for gestation and birth weight, rickets significantly correlated with severe PNAC and with moderate/severe BPD. Serum peak alkaline phosphatase levels were significantly elevated in rickets (P < 0.001). In ELBW infants, the incidence of rickets of prematurity remains high and the incidence of severe PNAC and moderate/severe BPD was significantly increased 18 and 3 times, respectively.     

Modes of death in neonatal intensive care units

With the ever-increasing availability of aggressive medical treatment and technical support, neonatologists are offered an increasing ability to prolong life. While "end-of-life" decisions within NICUs have been studied internationally, there is limited data available for Ireland. Through the auspices of the Irish Faculty of Paediatrics 2002 Neonatal Mortality Ouestionnaire, decisions made around the time of death in Irish Neonatal Intensive Care Units were examined. The overall response rate to the questionnaire was 96% (n=25). One hundred and eighty seven deaths were reported for 2002. Information pertaining to the mode of death was available in 53% of cases. Seventy seven percent of those paediatricians who answered this question, reported either withdrawing or withholding treatment in babies thought to have a hopeless outcome, with the greatest proportion of these deaths occurring in premature infants (n=30) and babies with congenital defects (n=40).     

试管婴儿(IVF-ET)新生儿期情况分析

目的前瞻性对体外授精-胚胎移植(IVF-ET)技术受孕出生的新生儿进行评估,探讨实施IVF-ET技术出生新生儿的安全性.方法从自2000年10月～2004年12月在本院接受IVF-ET治疗后受孕181例孕妇进行前瞻性追踪观察,将其分娩的新生儿254个作为观察组,本院产科自然妊娠分娩的新生儿1205个作为对照组,对两组单胎和总体新生儿胎龄、出生体重、Apgar评分、高胆红素血症、新生儿窒息、新生儿死亡及新生儿畸形发病率的进行观察比较.结果单胎新生儿的出生体重、Apgar评分、新生儿死亡率及新生儿畸形率与对照组无差异性(P＞0.05);单胎新生儿窒息率观察组低于对照组,两组比较有显著差异性(P＜0.05).两组总体比较新生儿畸形、新生儿窒息率、新生儿死亡率无差异性(P＞0.05),而新生儿低体重出生率、高胆红素血症、住院治疗时间,观察组明显高于对照组,两组比较有极显著差异性(P＜0.01);而Apgar评分观察组低于对照组两者比较有差异性(P＜0.05).结论 IVF-ET技术不增加新生儿畸形和围产期死亡率;多胎是IVF-ET技术主要并发症,是早产和低体重出生儿、高胆红素血症、新生儿窒息等新生儿不良结局的主要原因.     

Survival of all cancer patients in Korea through 2-year follow-up

Cancer is the most frequent cause of death in both developing and developed countries, including Korea. The aim of this study was to present survival rates of Korean cancer patients. Survival analysis was carried out with data collected under the Korea Central Cancer Registry Program, which included all cancer patients diagnosed from January 1, 1997 to December 31, 1997. We have analyzed the effects of age at diagnosis and sex on cancer survival from the cancer registry data of 64,240 Korean patients diagnosed of cancer in 1997. The overall survival rate of all Korean cancer patients (both men and women) was 67% at 1 yr and 57% at 2 yr. The 1- and 2-yr survival rates for all cancers in men were 58% and 47%, respectively, while those in women were 77% and 69%, respectively. Men had a lower survival rate than women in most malignancies. The pancreatic cancer was shown the lowest 1-yr survival rate.     

Polymorphisms of genes involved in innate immunity: association with preterm delivery

An altered inflammatory activity due to functionally relevant polymorphisms of the innate immune system may influence pathways leading to labour and, therefore, impact on the frequency of preterm birth. We examined five polymorphisms of the innate immune system in a large cohort of preterm very-low-birth-weight (VLBW, n = 909) and term-born infants (n = 491) and their mothers (n = 747). The primary outcome was preterm versus term birth. Frequencies of polymorphisms in mothers of term-born infants versus mothers of VLBW infants and term infants versus preterm VLBW infants (singletons) are given. Homozygous CD14-159T: 18.5 versus 21.8% (mothers) and 19.6 versus 21.2% (infants). Homozygous interleukin IL-6-174G: 28.8 versus 38% (P = 0.018, mothers) and 30 versus 32.7% (infants). Homozygous or heterozygous nuclear oligomerization domain NOD2-3020insC: 6.9 versus 6.1% (mothers) and 5.7 versus 5.1% (infants). Heterozygous or homozygous toll-like-receptor TLR2-Arg753Gln: 6.9 versus 6.1% (mothers) and 5.7 versus 5.1% (infants). Homozygous or heterozygous TLR4-896G: 8.1 versus 11.5% (mothers) and 11.6 versus 10.5% (infants). Although the homozygous maternal IL-6-174G genotype was found to be independently associated with preterm delivery in multivariate regression analysis, the incidence of intrauterine infection was not significantly increased in mothers of preterm VLBW-infants, carrying this or other polymorphisms of the innate immune system. The overall influence of the investigated polymorphisms on the development of preterm delivery seems moderate, since only the maternal IL6-174G genotype was associated with preterm birth and none of the polymorphisms were associated with intrauterine infection as the cause of preterm birth.     

Mental health and resiliency following 44 months of terrorism: a survey of an Israeli national representative sample

Background

Genetic variation in the innate immune system of the host may play a role in determining the risk of developing infection, as well as outcome from infection.

Methods

Infectious complications were retrospectively determined in 293 (233 African-American (AA), 57 Caucasian and 3 Hispanic) mechanically ventilated very low birth weight (VLBW) infants (<1500 grams at birth) who were genotyped for the IL-6 -174 G/C, IL-10 -1082 G/A and CD14 -260 C/T single nucleotide polymorphisms (SNPs).

Results

The IL-6 -174C allele was associated with an increased incidence of late blood stream infection (BSI) in AA but not Caucasian infants. In AA infants with the C allele the incidence of late BSI was 20/29 (69%) compared to 94/204 (46%) in homozygous GG infants (RR 2.6, 95% CI: 1.1–6.0, p = 0.021). The IL-10 -1082A allele was associated with an increased incidence of late BSI. One or more episodes of late BSI developed in 14 (35%) of 40 infants with the GG genotype, 71 (49%) of 145 infants with the GA genotype and 63 (58%) of 108 infants with the AA genotype (p = 0.036). Infants with the A allele (AA or GA genotypes) had an incidence of late BSI that was 134/253 (53%) compared to 14/40 (35%) in homozygous GG infants (RR 2.1, 95% CI: 1.04–4.19, p = 0.035). The CD14 -260 C/T SNP did not alter the overall risk for BSI in ventilated VLBW infants. Multiple BSI episodes were more common in the TT genotype group (CC: 17%, CT: 11%, TT: 30%, p = 0.022). This effect was due to the strong effect of the TT genotype on the incidence of multiple BSI in AA infants (CC: 15%, CT: 11%, TT: 39%, p = 0.003).

Conclusion

The IL-6 -174 G/C, IL-10 -1082 G/A and CD14 -260 C/T SNPs may alter risk for BSI in ventilated VLBW infants.     

Pathologic features of long-standing "healed" bronchopulmonary dysplasia: a study of 28 3- to 40-month-old infants

Alveolar septal fibrosis, the main residual feature in the "healed" stage of bronchopulmonary dysplasia (BPD), was the consistent finding in 28 infants who died at 3 to 40 months of age, all having had moderate to severe BPD in the neonatal period. The cause of death in 68 per cent of the cases was progressive respiratory failure related directly to the residual changes. An additional 18 pe cent of the infants died of pneumonia superimposed on the long-standing healed bronchopulmonary dysplasia. Cardiomegaly was present in 84 per cent of the cases; biventricular hypertrophy was present in 29 per cent of the cases, right ventricular hypertrophy alone in 21 per cent, and left ventricular hypertrophy alone in 21 per cent. Evidence of pulmonary hypertensive vascular disease was found in 68 per cent of the cases. The pulmonary changes of alveolar septal fibrosis are strikingly variable within individual infants, with moderate or severe fibrosis in one area and normally inflated or hyperinflated lung in the adjacent sublobule or lobe. It is postulated that this variability may be related to a protective effect of necrotizing bronchiolitis (a prominent feature of the acute stages of BPD), whereby the occlusion of the bronchioles shields the distal sublobule from the high oxygen tensions and ventilatory pressures used in treating BPD.     

The association of γδ-T cells with bronchopulmonary dysplasia in premature infants

BackgroundAs the survival rate of premature infants increases, the incidence of bronchopulmonary dysplasia (BPD), a chronic complication of premature infants, is also higher than before. The pathogenesis of BPD is complicated, and immune imbalance and inflammatory response may play important roles in it.ObjectiveTo investigate the correlation between lymphocyte subsets in peripheral blood, especially γδ-T cells, and BPD of preterm infants.Materials and methodThe study was carried out with the peripheral blood of premature infants (GA < 32 weeks, BW < 1500 g), which were collected at 24 h or 3–4 weeks after birth. The infants were divided into non-BPD groups and BPD groups that were classified as mild or moderate and severe in preterm infants based on the magnitude of respiratory support at 28 days age and 36 weeks postmenstrual age. The γδ-T, CD3+, CD4+, CD8+ and total lymphocyte subsets in peripheral blood were detected by flow cytometry.ResultsThe percentages of T lymphocyte subsets in peripheral blood were not different between BPD and non-BPD within 24 h after birth. And no significant difference was found in T lymphocyte subsets among neonates with BPD of different severities. However, the infants who developed BPD had a significant increase in γδ-T cells compared to non-BPD ones within 3–4 weeks after birth.ConclusionsIt seems that γδ-T cells in peripheral blood are correlated with BPD. However, the causality of BPD and various lymphocytes remains unclear, which need to be further studied.