Expert consensus on the diagnosis, treatment, and prevention of respiratory syncytial virus infections in children.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading global cause of respiratory infections and is responsible for about 3 million hospitalizations and more than 100,000 deaths annually in children younger than 5 years, representing a major global healthcare burden. There is a great unmet need for new agents and universal strategies to prevent RSV infections in early life. A multidisciplinary consensus development group comprising experts in epidemiology, infectious diseases, respiratory medicine, and methodology aims to develop the current consensus to address clinical issues of RSV infections in children. DATA SOURCES: The evidence searches and reviews were conducted using electronic databases, including PubMed, Embase, Web of Science, and the Cochrane Library, using variations in terms for "respiratory syncytial virus", "RSV", "lower respiratory tract infection", "bronchiolitis", "acute", "viral pneumonia", "neonatal", "infant" "children", and "pediatric". RESULTS: Evidence-based recommendations regarding diagnosis, treatment, and prevention were proposed with a high degree of consensus. Although supportive care remains the cornerstone for the management of RSV infections, new monoclonal antibodies, vaccines, drug therapies, and viral surveillance techniques are being rolled out. CONCLUSIONS: This consensus, based on international and national scientific evidence, reinforces the current recommendations and integrates the recent advances for optimal care and prevention of RSV infections. Further improvements in the management of RSV infections will require generating the highest quality of evidence through rigorously designed studies that possess little bias and sufficient capacity to identify clinically meaningful end points.

Treatment of pediatric mild persistent asthma with low-dose budesonide inhalation suspension vs. montelukast in China.

BACKGROUND: There are limited studies comparing budesonide inhalation suspension (BIS) with montelukast in real-world settings where treatment adherence and persistency may be suboptimal. This real-world study aims to investigate the control effectiveness of montelukast or BIS as a monotherapy in Chinese children with mild asthma. METHODS: Data were derived from a retrospective questionnaire-based analysis of 2‒14-year-old children with mild persistent asthma, who received either 500 µg of BIS (n = 153) or 4‒5 mg of montelukast (n = 240) once daily. The indicators of asthma control, the Asthma Control Test (ACT)/Childhood ACT (C-ACT) score, and the asthma-related medical costs were assessed. The differences between the two groups were compared using an unpaired t-test (normally distributed), Mann-Whitney U test (non-normally distributed) or chi-squared test (categorical variables). RESULTS: Medication compliance in the past 3-month period was better in the montelukast group than in the BIS group (P = 0.042). The montelukast group exhibited better asthma control in the past 4-week period, including lower percentages of asthmatic children with symptoms more than twice a week (P = 0.021), had night waking or night coughing (P = 0.022), or required reliever medication more than twice a week (P < 0.001). The montelukast group had a lower percentage of children with an ACT/C-ACT score ≤ 19 (P = 0.015). Caregivers reported a significantly better exercise tolerance in the children who received montelukast vs. BIS in the past 12 months (P < 0.001). Significantly higher medical expenditures attributable to asthma in the past 12 months were observed in the BIS group vs. montelukast group (P < 0.001). CONCLUSION: Both treatments provided acceptable overall asthma control in children with mild persistent asthma; however, more reliever medication and more medical expenditures attributable to asthma were needed for BIS vs. montelukast in real-world settings, where factors such as compliance were also taken into account.

[Retrospective Study of Mite-Specific Subcutaneous Immunotherapy in Children].

OBJECTIVE: To explore the clinical efficacy and influencing factors of children receiving mite-specific subcutaneous immunotherapy (SCIT). METHODS: We retrospectively analyzed the data of children who had received mite SCIT for 3 years at the Desensitization Center of our hospital. We used the daily medication score (DMS) to evaluate the medication use status (the higher the score, the higher the amount of medications given and the less satisfactorily was the primary disease controlled) and we used the visual analogue scale (VAS) to evaluate clinical symptoms (the higher the score, the more severe the symptoms). Evaluation was performed after the first SCIT treatment and after treatment was given for 3 months, 4 months, 12 months, and 3 years. According to whether medication for the primary disease was stopped after 3 years, the patients were divided into two groups, the discontinued medication group (discontinued group) and the continued medication group (continued group). The general data, DMS, VAS and the decline rate of the two groups were compared, and logistic regression was performed to analyze the influencing factors of the outcome. RESULTS: A total of 711 children were enrolled in the study, with an average age of 8.38 years at the time of the first visit to the hospital. There were 442 males and 269 females. Skin prick test showed that 445 cases only had mite allergy, and 266 cases had mite allergy combined with other allergies. 360 cases have discontinued the medication for the primary disease after 3 years, and 351 cases had relieved symptoms, but still needed to continue with the medication. At the beginning of SCIT treatment, the DMS and VAS of the discontinued group were lower than those of the continued group ( P<0.05). Evaluations from 3 months to 3 years showed that both DMS and VAS continued to decrease compared with those from the beginning, and the decline rate of DMS and VAS of the discontinued group was higher than that of the continued group after 3 years of SCIT ( P<0.05). After 3 months of SCIT, the positive rates of nasal and ocular symptoms in the discontinued group were lower than those in the continued group ( P<0.05). After 3 years of SCIT, the positive rates of nasal, ocular, and chest symptoms in the discontinued group were lower than those in the continued group ( P<0.05). Univariate analysis combined with multivariate logistic regression showed that initial DMS>4 points and initial VAS>3.5 points were protective factors for the discontinuation of the medication for the primary disease at the end of 3 years of SCIT, while the female sex and DMS reduction rate after 12 months of treatment>50% were risk factors for discontinuation. CONCLUSIONS: Mite SCIT can help relieve clinical symptoms and reduce the use of medication for symptomatic treatment. Symptoms can be improved after 3 months of SCIT, with the fastest improvement shown in nasal and eye symptoms. It is not recommended to discontinue the medication for the primary disease for too much after 1 year of treatment.

LncRNA-AK149641 regulates the secretion of tumor necrosis factor-α in P815 mast cells by targeting the nuclear factor-kappa B signaling pathway.

Long noncoding RNAs play important roles in various biological processes. However, not much is known about their roles in inflammatory response. Mast cells, involved in innate and adaptive immunity, are one of the major effector cells in allergic inflammatory reactions and contribute to the pathogenesis of disorders, including asthma. In the present study, we aimed to verify and elucidate the function and possible role of a novel lncRNA, called lncRNA-AK149641, in the mechanism of lipopolysaccharide (LPS)-induced inflammatory response in P815 mast cells. The results showed that downregulating lncRNA-AK149641 decreased secretion of tumor necrosis factor-α into the supernatants of LPS-stimulated mast cells. Mechanistically, the activity of nuclear factor-kappa B (NF-κB) decreased after downregulating lncRNA-AK149641, as shown by western blot and electrophoretic mobility shift assays. Moreover, RNA binding protein immunoprecipitation (RIP) verified that lncRNA-AK149641 was able to bind to NF-κB in the nucleus. In conclusion, we demonstrated that lncRNA-AK149641 regulated LPS-induced inflammatory response in mast cells through the NF-κB signaling pathway.

MiR-221 promotes IgE-mediated activation of mast cells degranulation by PI3K/Akt/PLCγ/Ca(2+) pathway.

Mast cells play a pivotal role in the immediate reaction in asthma. In a previous study, it was found that MicroRNA-221 (miR-221) was associated with asthma. Hence, in the present study, the role and the potential mechanisms of miR-221 on immunoglobulin E (IgE)-mediated activation of mast cells degranulation were investigated. MiR-221 expression was first quantified by qRT-PCR in IgE-mediated activation of mast cells. RBL-2H3 cells were then transfected with miR-221 mimic or miR-221 inhibitor, the IgE-mediated degranulation was detected in mast cells. The influence of miR-221 on expression of phospholipase C gamma (PLCγ1), p-PLCγ1, protein kinase B (Akt), phospho-Akt (p-Akt), inhibitor of kappa B (IκB-α), and phospho-IκB-α (p-IκB-α) were examined by Western blot, whereas free calcium ion (Ca(2+)) level was measured by flow cytometry and NF-κB expression was determined by EMSA. Phosphoinositide 3-kinase (PI3K)-inhibitor (LY294002) and NF-κB-inhibitor [pyrrolidine dithiocarbamate (PDTC)] were used to investigate the role of PI3K/Akt pathway and NF-κB in miR-221 promoting IgE-mediated activation of mast cells degranulation. The expression of miR-221 was upregulated in IgE-mediated activation of mast cells, and it was overexpressed in miR-221 mimic transfected cells. The degranulation was found to be significantly increased in miR-221 overexpressed cells while it was found to be significantly decreased in miR-221 downregulated cells. The expression of p-PLCγ1, p-Akt, p-IκB-α as well as NF-κB and Ca(2+) release were increased in miR-221 overexpressed cells. PI3K-inhibitor (LY294002) could rescue the promotion of degranulation caused by miR-221 in IgE-mediated activation of mast cells. However, NF-κB-inhibitor (PDTC) could not rescue the promotion of degranulation caused by miR-221 in IgE-mediated activation of mast cells. MiR-221 promotes IgE-mediated activation of mast cells degranulation by PI3K/Akt/PLCγ/Ca(2+) signaling pathway, in a non-NF-κB dependent manner.

Indoor Allergen Levels and Household Distributions in Nine Cities Across China.

OBJECTIVE: Chinese allergic subjects have high levels of sensitization to house dust mite (HDM) and other indoor allergens. This study quantifies common indoor allergen levels in Chinese households. METHODS: Dust samples were collected from nine cities. Major allergens Der p 1 and Der f 1 from Dermatophagoides pteronyssinus and D. farinae, and specific antigens of Blomia tropicalis, Tyrophagus putrescentiae, Acarus siro, and cockroach species Blattella germanica and Periplaneta americana were measured by ELISA. RESULTS: HDM allergens were found in dust samples from bedding in 95% of the Chinese households. The median levels varied from <0.006 to 9.2 µg/g of dust, depending on the city. The percentages of households having HDM allergen levels associated with the risk of developing allergy sensitization and asthma were 65% and 25%, respectively. Specific antigens of the storage mite and cockroach were only found in samples from the southern and tropical regions of China. Levels of mite allergens were generally higher in samples from bedding compared to samples from the living room, even for storage mites, whereas levels of cockroach antigens were higher in the living room samples. CONCLUSION: HDM allergens are present in bedding dust samples from most Chinese households. Cities in southern and central China have relatively high levels of HDM major allergens compared to cities in northern and western China. Antigens of storage mites and cockroaches are not as common as HDM allergens.

Down-regulation of microRNA-223 promotes degranulation via the PI3K/Akt pathway by targeting IGF-1R in mast cells.

BACKGROUND: Mast cells play a central role in allergic and inflammatory disorders by inducing degranulation and inflammatory mediator release. Recent reports have shown that miRNAs play an important role in inflammatory response regulation. Therefore, the role of miR-223 in mast cells was investigated. METHODS: The expression of miR-223 was quantified by quantitative real-time polymerase chain reaction (qRT-PCR) in immunoglobulin E (IgE)-mediated mast cells. After successful miR-223 inhibition by transfection, degranulation was detected in IgE-mediated mast cells. The phosphorylation of IκB-α and Akt were examined using western blotting. NF-κB was tested using electrophoretic mobility shift assay. PI3K-inhibitor (LY294002) was used to investigate whether the PI3K/Akt pathway was essential for mast cell activation. The TargetScan database and a luciferase reporter system were used to identify whether insulin-like growth factor 1 receptor (IGF-1R) is a direct target of miR-223. RESULTS: MiR-223 expression was up-regulated in IgE-mediated mast cells, whereas its down-regulation promoted mast cell degranulation. Levels of IκB-α and Akt phosphorylation as well as NF-κB were increased in miR-223 inhibitor cells. LY294002 could block the PI3K/Akt signaling pathway and rescue the promotion caused by suppressing miR-223 in mast cells. IGF-1R was identified as a direct target of miR-223. CONCLUSIONS: These findings suggest that down-regulation of miR-223 promotes degranulation via the PI3K/Akt pathway by targeting IGF-1R in mast cells.

Effects of sublingual immunotherapy for Dermatophagoides farinae on Th17 cells and CD4(+) CD25(+) regulatory T cells in peripheral blood of children with allergic asthma.

BACKGROUND: Sublingual immunotherapy is becoming a more common treatment for allergic diseases, particularly in pediatric clinics. This type of treatment is highly effective for Dermatophagoides farinae allergy, but the mechanisms resulting in immune tolerance have not been investigated. We explored the effects of sublingual immunotherapy with D. farinae drops on populations of subsets of T immune cells, specifically Th17 cells and CD4(+) CD25(+) regulatory T cells (Treg cells), in peripheral blood of children with allergic asthma. METHODS: We assessed immune cell populations in 60 patients allergic to D. farinae who were randomly divided into 2 groups: a treatment group (n = 30) and a control group (n = 30), treated with sublingual administration of D. farinae drops or placebo, respectively, for 48 weeks. Clinical symptoms of asthma were scored for each individual before and after treatment, and the percentages of Th17 cells and CD4(+) CD25(+) Treg cells in the peripheral blood were evaluated by flow cytometry at 12-week intervals beginning at baseline. RESULTS: Both the mean daily symptom scores and percentages of Th17 cells significantly declined in the treatment group throughout the study period (p < 0.05), and in the control group both declined but without significant differences between time points. In contrast, the percentages of Treg cells significantly increased in the treatment group throughout the study period (p < 0.05), but no statistical difference was observed among different sampling times. CONCLUSION: Sublingual administration of D. farinae drops alters T immune cell profiles and reduces asthma symptoms, likely resulting in enhanced immunosuppression in children with asthma.

A cross-sectional study of the clinical characteristics of hospitalized children with community-acquired pneumonia in eight eastern cities in China.

BACKGROUND: Community-acquired pneumonia in children is common in China. To understand current clinical characteristics and practice, we conducted a cross-sectional study to analyze quality of care on childhood pneumonia in eight eastern cities in China. METHODS: Consecutive hospital records between January 1, 2010 and December 31, 2010 were collected from 13 traditional Chinese medicine (TCM) and western medicine (WM) hospitals in February, May, August, and November (25 cases per season, 100 cases over the year), respectively. A predesigned case report form was used to extract data from the hospital medical records. RESULTS: A total of 1298 cases were collected and analyzed. Symptoms and signs upon admission at TCM and WM hospitals were cough (99.3% vs. 98.6%), rales (84.8% vs. 75.0%), phlegm (83.3% vs. 49.1%), and fever (74.9% vs. 84.0%) in frequency. Patients admitted to WM hospitals had symptoms and signs for a longer period prior to admission than patients admitted to TCM hospitals. Testing to identify etiologic agents was performed in 1140 cases (88.4%). Intravenous antibiotics were administered in 99.3% (595/598) of cases in TCM hospitals and in 98.6% (699/700) of cases in WM hospitals. Besides, Chinese herbal extract injection was used more frequently in TCM hospitals (491 cases, 82.1%) than in WM hospitals (212 cases, 30.3%) (p < 0.01). At discharge, 818 cases (63.0%) were clinically cured, with a significant difference between the cure rates in TCM (87.6%) and WM hospitals (42.0%) (OR = 9.8, 95% confidence interval (CI): 7.3 ~ 12.9, p < 0.01). Pathogen and previous medical history were more likely associated with the disappearance of rales (OR = 7.2, 95% CI: 4.8 ~ 10.9). Adverse effects were not reported from the medical records. CONCLUSIONS: Intravenous use of antibiotics is highly prevalent in children with community-acquired pneumonia regardless of aetiology. There was difference between TCM and WM hospitals with regard to symptom profile and the use of antibiotics. Intravenous use of herbal injection was higher in TCM hospitals than in WM hospitals. Most of the cases were diagnosed based on clinical signs and symptoms without sufficient confirmation of aetiology. Audit of current practice is urgently needed to improve care.

[Long-term efficacy of sublingual immunotherapy with Dermatophagoides Farianae Drops in children with allergic asthma sensitized to dust mites].

OBJECTIVE: To observe the efficacy of sublingual immunotherapy (SLIT) in children with allergic asthma during the treatment and 1 year after the treatment. METHOD: This is an open and retrospective study; 80 children with mild-moderate allergic asthma between 4 and 14 years of age were chosen from the Department of Respiratory Medicine, Nanjing Children's Hospital Affiliated to Nanjing Medical University from May to August, 2009. All children were sensitized to Dermatophagoides Farianae and/or Dermatophagoides Pteronyssinus and have received anti-asthma drug therapy for 3 months (baseline). Thirty-nine children in SLIT group underwent 2-year SLIT and combined with anti-asthma drug, these children were then followed up for 1 year. Forty-one children in drug group only received anti-asthma drug and were followed up for 3 years. The scores of asthma symptom, scores of asthma medication and the number of discontinuation of anti-asthma drug were compared between the SLIT group and drug group for the baseline, end of the 2nd year and 3rd year treatment. The frequency of acute attack of asthma was also compared between the two groups for 1 year before the treatment and the 3rd year treatment. RESULT: (1) At baseline, the asthma symptom scores, the medication scores and the frequency of acute attack of asthma in 1 year before the treatment of the two groups showed no significant difference. (2) After 2-year SLIT, the daytime asthma symptom scores of SLIT group were lower than the drug group (0.18 ± 0.06,0.93 ± 0.12,Z = -4.873, P < 0.05), the night asthma symptom scores of the two groups showed no significant difference. One year after SLIT, the daytime and night asthma symptom scores of SLIT group were both lower than those of the drug group (daytime SLIT group vs. Drug group: 0.18 ± 0.06 vs. 1.46 ± 0.72,Z = -5.082, P < 0.05;night SLIT group vs. Drug group: 0.05 ± 0.04 vs. 0.66 ± 0.14,Z = -4.019, P < 0.05). (3) At the end of SLIT and 1 year after SLIT, the medication scores of SLIT group were both lower than those of the drug group (End of SLIT SLIT group vs. Drug group: 0.31 ± 0.07 vs. 0.75 ± 0.12,Z = -2.813, P < 0.05;1 year after SLIT SLIT group vs. Drug group: 0.17 ± 0.06 vs. 0.87 ± 0.17,Z = -4.106, P < 0.05), the number of discontinuation of anti-asthma drug of SLIT group were both more than the drug group (End of SLIT SLIT group vs. Drug group: 20 vs. 10,χ(2) = 6.167, P < 0.05;1 year after SLIT SLIT group vs. Drug group: 29 vs.13,χ(2) = 14.581, P < 0.05).(4) In the 3rd year, the frequency of acute attack of asthma in SLIT group was significantly lower than that of drug group (0.69 ± 1.20, 1.20 ± 1.44,Z = -1.968, P < 0.05) . CONCLUSION: SLIT can significantly improve the symptoms of asthma, reduce the use of anti-asthma drug and reduce the frequency of the acute attack of asthma. Meanwhile, the efficacy could still maintain 1 year after the SLIT treatment.

Profiling of miRNAs in pediatric asthma: upregulation of miRNA-221 and miRNA-485-3p.

The aim of this study was to investigate the expression profiles of microRNAs (miRNAs) in pediatric asthma and to determine candidate miRNAs responsible for the pathogenesis of this disease. Microarrays were used to detect the differences in the miRNA expression levels between asthmatic children and controls. Airway inflammation was evaluated by cell counting and tissue biopsy in an ovalbumin (OVA)-induced murine asthma model. Real-time polymerase chain reaction (PCR) was used to verify the differentially expressed miRNAs. The targets of the identified miRNAs were analyzed by bioinformatic analysis. The sprouty-related protein with an EVH1 domain-2 (Spred-2) protein content was assessed by western blotting. Differences were observed in the expression of miRNAs between the asthmatic children and controls. Upregulation of miRNA-221 and miRNA-485-3p in pediatric asthmatics and murine asthma models were verified by real-time PCR. Spred-2, a predicted target of miRNA-221 and miRNA-485-3p, was downregulated in murine asthma models. Upregulation of miRNA-221 and miRNA-485-3p may regulate the pathogenesis of asthma.

Inhibition of miRNA-221 suppresses the airway inflammation in asthma.

This study investigated the expression of miRNA-221 in asthmatics in order to determine whether miRNA-221 plays a role in the development of asthma. Real-time PCR was used to detect the miRNA-221 in both asthmatic and control subjects. In addition, airway inflammation was evaluated by cell counting and tissue biopsy in the OVA-induced murine asthma model. miRNA-221 was differentially expressed in asthmatics and control subjects, and miRNA-221 blockade resulted in a reduction of airway inflammation in the OVA-induced murine asthma model. We conclude that miRNA-221 participates in the pathogenesis of asthma and that inhibition of miRNA-221 suppresses airway inflammation in asthmatics.

Correlation between serum H2S and pulmonary function in children with bronchial asthma.

Endogenous hydrogen sulfide (H2S) has generated recent research interest because of its potential function as an inflammatory mediator. Despite its apparent functions in vascular smooth muscle, an important player in airway remodeling in asthma, little research has been done to assess the role of H2S in the pathogenesis of asthma. To determine whether serum H2S concentration is correlated with pulmonary function in children with asthma, we measured serum H2S concentration and pulmonary function indices (FVC, FEV1, PEF, FEF25-75, MEF50 and MEF25) in 64 children with asthma and 60 healthy children. Pearson's correlation was used to determine the relationship between serum H2S concentration and lung function parameters. Compared to healthy children, both serum H2S concentration and all lung function parameters were significantly decreased in children with asthma (P<0.05). Furthermore, serum H2S concentration was positively correlated with lung function indices (P<0.05). Thus, decreasing levels of H2S in the serum may be used to indicate decreasing lung function. Further investigation into the causality behind these findings is required.

[Isolated pulmonary Langerhans cell histiocytosis in a two-year-old child: case report and literature review].

OBJECTIVE: To improve the recognition of the clinical features and results of laboratory examination for isolated pulmonary Langerhans cell histiocytosis (PLCH) in children. METHOD: The information of one case with isolated PLCH was analyzed and reports of 11 cases with isolated PLCH were reviewed. RESULT: The patient we report is only 2 years old with 1 month of course of disease, manifesting with prominent pulmonary involvement: cough and short of breath; CT scan of the chest showed punctiform, nodular and reticular high density opacities involving all lobes of both lungs. Biopsy of the lung tissue showed expression of CD1a, CD68, S-100, consistent with the diagnosis of LCH. He received prednisolone, VP16 and Vindesine with good response. Ten of 11 cases of isolated PLCH reported before manifesting with cough and dyspnea, CT scan of the chest showed interstitial lung changes (5/8), cystic changes (5/8), small nodules (2/8) and pneumothorax (2/8). Langerhans cells were found in 9 cases on lung biopsy, part of biopsy lung tissues were stained with anti-CD1a, the alveolar lavage fluid of the other 2 cases were stained with S-100 and anti-CD1a. CONCLUSION: Isolated PLCH is rarely reported in children. It manifested with prominent pulmonary involvement: cough and short of breath, and CT scan of the chest showed interstitial lung changes, small nodules or cysts involving the lung, Langerhans cell could be found in lung biopsy, and the immunohistochemical staining in lung biopsy lung and alveolar lavage fluid stained with S-100 and anti-CD1a antibodies.

[Molecular epideiological and clinical feature of human metapneumovirus in children with acute respiratory tract infection in Nanjing City].

OBJECTIVE: To investigate the molecular epideiological and clinical feature of human metapneumovirus in children with acute respiratory tract infection in Nanjing city, China. METHOD: Nasopharyngeal aspirates and nasopharyngeal swab were taken from 642 outpatients or hospitalized pediatric patients with acute at the Children Hospital of Nanjing, Jiangsu Province, China, between August 2009 and July 2010. Respiratory speciments were tested for the M gene of hMPV by reverse-transcription polymerase chain reaction (RT-PCR). All RT-PCR positive products were sequenced and phlogenetic analysis was conducted. RESULT: hMPV was detected in 35 (5.5%) of the 642 children. Phylogenetic analysis revealed that 51.4% of the hMPV were B1, 31.4% were A2b. The peak of the positive rate was in April. The majority of the hMPV-positive patients(71.4%) were 0-1 years old. Of the 35 hMPV-positive patients, 15 (42.8%) were co-infected with other respiratory viruses, and human rhinovirus (HRV) were the most common additional respiratory virus. The most common clinical diagnosis was pneumonia (48.6%). CONCLUSION: Human metapneumovirus is an important pathogen of acute respiratory tract infection in children in Nanjing city. The subtype B1 was the predominating lineage in 2009-2010 in Nanjing city. No significant differences were found for clinical characteristics between genotype A and genotype B human metapneumovirus infection in children in Nanjing.

[Effect of maternal vitamin D deficiency on lung morphogenesis and platelet-derived growth factor-A expression in rat offspring].

OBJECTIVE: To study the effect of maternal vitamin D deficiency on lung morphogenesis and platelet-derived growth factor-A (PDGF-A) expression in rat offspring. METHODS: Sprague-Dawley (SD) female rats were randomly divided into two groups: normal control and vitamin D deficiency, with 6 rats in each group. The vitamin D deficiecy group was kept away from light and fed with the forage without vitamin D. After 2 weeks, the rats were mated with normal SD male rats. The morphological changes of fetal rat lungs on day 20 of gestation and 1-day-old neonatal rat lungs were observed by light microscope and electronic microscope. The levels of PDGF-A mRNA and protein in fetal and neonatal rat lungs were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) technique and Western blot method respectively. RESULTS: Under the light microscope, smaller alveolar space, smaller diameter of the respiratory membrane and thicker alveolus mesenchyma were observed in lungs of fetal and neonatal rats from the vitamin D deficiency group compared with the controls (P<0.05). Under the electronic microscope, fewer lamellar bodies but more glycogen deposition in intracytoplasm were observed in the lungs of fetal rats from the vitamin D deficiency group compared with the controls. There was an increased number of empty lamellar bodies in neonatal rats from the vitamin D deficiency group. The levels of PDGF-A mRNA and protein in lungs of fetal and neonatal rats from the vitamin D deficiency group were significantly lower than the controls (P<0.05). CONCLUSIONS: Maternal vitamin D deficiency during pregnancy may inhibit the development of lung morphogenesis and PDGF-A expression in late fetal and neonatal rats. The low expression of PDGF-A may be involved in the inhibitory effect of vitamin D deficiency on the lung development.