[Hereditary hemorrhagic telangiectasia]

Hereditary hemorrhagic telangiectasia, also known as Rendu-Osler - Weber disease, is a rare, autosomal dominant vascular disease, with prevalence of 1/5,000. The condition is characterized by muco-cutaneous telangiectasias, which are responsible for a hemorrhagic syndrome of variable severity, as well as arteriovenous malformations (AVMs) appearing in the lungs, the liver, and the nervous system. They can be the source of shunts, which may be associated with high morbidity (neurological ischemic stroke, brain abscess, high-output heart failure, biliary ischemia…). It is therefore crucial to establish a clinical diagnosis using the Curaçao criteria or molecular diagnosis based on genetic analysis of the ENG, ACVRL1, SMAD4 and GDF2 genes. In most cases, multidisciplinary management allows patients to have normal life expectancy. Advances in interventional radiology and better understanding of the pathophysiology of angiogenesis have resulted in improved therapeutic management. Anti-angiogenic treatments, such as bevacizumab (BVZ, an anti-VEGF antibody), have proven to be effective in cases involving bleeding complications and severe liver damage with cardiac repercussions. Other anti-angiogenic agents are currently being investigated, including tyrosine kinase inhibitors.

Bacterial killing is enhanced by exogenous administration of lysozyme in the lungs

OBJECTIVE

Lysozyme, a 14-kDa protein, is one of the most abundant antimicrobials in the lungs. Its concentration in airway surface sufficient to kill several bacterial pathogens in vitro. The purpose of this study was to determine if administration of exogenous lysozyme would further enhance bacterial killing in vivo.

METHODS

To assess the effect of acute lung infection on endogenous lysozyme protein levels, mice were infected by intratracheal instillation of Pseudomonas aeruginosa and bronchoalveolar (BAL) fluid assessed for lysozyme concentration and for muramidase activity. In order to inform in vivo testing, species-specific bacterial killing efficacy was determined by incubating mucoid P. aeruginosa with 2×10⁵ units of chicken lysozyme, human lysozyme or with vehicle at 37°C for 2hours. Subsequently, mice challenged with intratracheally-administered mucoid P. aeruginosa, were reintubated and injected with 2×10⁵ Units of native human lysozyme, recombinant human lysozyme or with vehicle. Lung bacterial burden was enumerated subsequently.

RESULTS

The concentration of lysozyme protein in BAL fluid from mice challenged with mucoid clinical isolate of P. aeruginosa was increased 4-fold at 6hours post-infection. Quantitative culture showed that the number of recoverable bacteria was significantly decreased by both chicken and human lysozyme compared to vehicle but human lysozyme was significantly more effective than chicken egg lysozyme. In vivo, 24hours post-infection quantitative culture of lung homogenates showed that the number of viable bacteria recovered from mice treated with either native or recombinant lysozyme was decreased with 0.76±0.25×10⁴ and 0.84±0.16×10⁴, respectively, vs. 7.0±2.52×10⁴ CFU/g protein in mice treated with HBSS, both P<0.05.

CONCLUSIONS

These results indicate that endogenous lysozyme is increased during acute lung infection and that early administration of exogenous lysozyme further enhances bacterial killing in vivo.

Protein-losing gastropathy associated with cytomegalovirus in two sisters - Case reports and review of the literature

Ménétrier's disease is a protein-losing gastropathy that is uncommon in childhood. Its symptoms are unspecific, with abdominal pain, vomiting, and edema. Blood tests show hypoproteinemia and hypoalbuminemia, and upper digestive endoscopy reveals giant gastric folds. In children, cytomegalovirus has been identified as a possible cause. Here we describe two sisters presenting with Ménétrier's disease, 2 years apart. This diagnosis should be considered in the presence of hypoalbuminemia in children when a nephrotic syndrome is excluded.

Sarcoidosis in children: HRCT findings and correlation with pulmonary function tests

RATIONALE

High-resolution computed tomography (HRCT) plays an important role in the diagnosis and staging of pulmonary sarcoidosis, but implies radiation exposure. In this light, we aimed to describe HRCT findings as well as their relationship with pulmonary function tests (PFT) in children with pulmonary sarcoidosis.

METHODS

In a retrospective study, 18 pediatric patients with sarcoidosis, including 12 with pulmonary abnormalities (PA group) and 6 without pulmonary abnormalities (APA group) were followed over a 16-year period. Relationships between HRCT scores and PFT were studied by non-parametric Spearman's test at diagnosis and by restricted maximum likelihood (REML) analysis during follow-up.

RESULTS

Forty-three HRCT were scored. Twelve patients showed abnormal HRCT findings at diagnosis with multiple nodules or micronodules, while ground-glass opacities were seen in 11 patients. Ten patients exhibited pleural thickening or thickening of the fissure and 6 had interlobular septal thickening at diagnosis. No correlation between HRCT and forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), forced expiratory flow during the mid-half of the FVC (FEF(25-75)) and specific dynamical compliance (SpecC(Ldyn)) was found at diagnosis. However, linear mixed models showed that changes in total HRCT scores over time were significantly associated with SpecC(Ldyn), FVC, and FEV1 modifications.

CONCLUSION

Radiologic findings in children with pulmonary sarcoidosis were similar to those in adults. HRCT and PFT are both essential investigations at diagnosis; however, the correlation between HRCT pulmonary parenchymal findings and PFT over time suggests the possibility of reducing the number of HRCT during follow-up to decrease unnecessary radiation exposure.

Massive splenomegaly and pancytopenia reuealing sarcoidosis in a child

Clinical presentation of sarcoidosis in children is very variable and dependant upon age. Herein, we report the first association of massive splenomegaly and pancytopenia as the revealing mode of sarcoidosis in an 8-year-old girl who, despite bone marrow involvement, had a remarkable good outcome following steroid therapy.

[Lung diseases in children associated with inherited disorders of surfactant metabolism]

Pulmonary surfactant is a unique mixture of lipids and specific proteins that reduces surface tension at the air-liquid interface, preventing collapse of the lung at the end of expiration. Recessive loss-of-function mutations of pulmonary surfactant protein B (SP-B) was initially described in infants who develop respiratory failure at birth. More recently, mutations in other constitutive surfactant proteins like surfactant protein C or implied in its metabolism like ATP-binding cassette, sub-family A, member 3 (ABCA3) or NK2 homeobox (NKX2-1) were identified in newborn with respiratory distress but also in children with diffuse infiltrative pneumonia. Intra-alveolar accumulation of protein related to surfactant dysfunction leads to cough, hypoxemia and radiological abnormalities including ground-glass opacities and lung cysts. The clinical and radiological features associated with these genetic disorders, along with their treatment and outcome, are reviewed.

[Bronchopulmonary dysplasia-associated pulmonary arterial hypertension of very preterm infants]

Bronchopulmonary dysplasia (BPD) of very preterm infants is a multifactorial chronic lung disease and its incidence has not decreased despite improvements in neonatal intensive care, including lung protective strategies. Pulmonary hypertension (PH) can complicate the course of BPD. Mortality in infants with BPD-associated PH is thought to be very high, but its incidence is unknown and a standard diagnostic and therapeutic strategy has not been well defined. In this article, we will first describe the current knowledge on the BPD-associated PH and the current treatments available for this pathology. We will then present the HTP-DBP Study, carried out in Paris (France) starting in 2012. The diagnosis of PH is suspected on echocardiographic criteria, but cardiac catheterization is considered the gold standard for diagnosis and evaluation of the severity of PH. Moreover, pulmonary vasoreactivity testing is used to guide the management of patients with PH. The pathogenesis of BPD-associated PH is poorly understood and even less is known about appropriate therapy. Today, optimizing ventilation and reducing the pulmonary vascular tone with specific pulmonary vasodilatator drugs are the main goals in treating HTP-associated DBP. Animal studies and a few clinical studies suggest that medications targeting the nitric oxide (NO) signaling pathway (NO inhalation, oral sildenafil citrate) could be effective treatments for BPD-associated PH, but they have not been approved for this indication. The HTP-DBP study is a French multicenter prospective observational study. The objective is to evaluate the frequency of BPD-associated PH, to describe its physiopathology, its severity (morbidity and mortality), and the effectiveness of current treatments.

[Genetic disorders of surfactant]

Lung diseases associated with surfactant metabolism disorders represent a significant but heterogeneous group of rare disorders. Intra-alveolar accumulation of protein related to surfactant dysfunction leads to cough, hypoxemia and radiological diffuse infiltration. Inherited deficiency of pulmonary surfactant protein B (SP-B) was initially described in term newborns who develop severe respiratory failure at birth. More recently, mutations in surfactant protein C (SP-C) or in proteins required for surfactant synthesis such as ATP-binding cassette, sub-family A, member 3 (ABCA3) or NK2 homeobox 1 (NKX2-1) were identified in newborns with respiratory distress but also in children with diffuse infiltrative pneumonia. The aim of this review is to describe the clinical presentation of these diseases but also the diagnostic tools and the treatments options available.

Surfactant protein C gene (SFTPC) mutation-associated lung disease: high-resolution computed tomography (HRCT) findings and its relation to histological analysis

AIM OF THE STUDY

Determine high-resolution tomography (HRCT) scan characteristics in children with SFTPC mutation and correlate them to histological findings.

PATIENTS AND METHODS

This retrospective multicenter study included 15 children (7 females and 8 males) with SFTPC mutations. HRCT scans have been performed in all the children and lung biopsies in 8 children.

RESULTS

From all signs assessed on initial HRCT scans, ground-glass opacities (n =14, 93%) and lung cysts (n = 6, 40%) were predominant. Interlobular septal thickening (n = 1, 7%), air space consolidation (n = 1, 7%), paraseptal emphysema (n = 2, 13%), and pulmonary nodules (n = 1, 7%) were also found. Histological analysis revealed accumulation of macrophages in the alveolar lumen, type II pneumocyte hyperplasia, and alveolar septal thickening. Dilatation of the respiratory bronchiole and alveolar duct associated with muscular hyperplasia were also described. Interestingly, lung cysts on HRCT scans were associated with dilatation of terminal bronchioli and alveolar duct in lung biopsies.

CONCLUSION

In children with SFTPC mutations, HRCT scan finding was highly correlated to the histological findings and, as such, represent a useful tool to identify patients that may require SFTPC gene sequencing.

[Pneumocystis jiroveci pneumonia during prolonged corticosteroid therapy in an immunocompetent infant]

INTRODUCTION

Pneumocystis jiroveci (PJ) infection is rare in infants and is suggestive of primary or secondary immunodeficiency. We report on a case of severe PJ pneumonia in an immunocompetent infant after prolonged corticosteroid treatment.

CASE REPORT

A 5 1/2 month-old girl presented with hypoxemic respiratory distress. Her medical record was remarkable only for a bulky parotid haemangioma, which was treated with prolonged oral corticosteroid therapy. The chest X-ray showed a mixed alveolar-interstitial pattern, and bronchoalveolar lavage revealed the presence of PJ. A favourable outcome was obtained after three weeks of intravenous trimethoprim-sulfamethoxazole treatment.

CONCLUSION

PJ infection should be suspected in infants presenting with progressive respiratory distress associated with a mixed alveolar-interstitial pattern. Its potential seriousness justifies prophylactic therapy during prolonged immunosuppressive treatment (chemotherapy, corticosteroid treatment).

Conservative use of chest-tube insertion in children with pleural effusion

The aim of this work was to evaluate the effect of a more conservative use of chest-tube insertion on the short-term and long-term outcome of pleural infection. Sixty-five patients with pleural infection, aged 1 month to 16 years were each treated according to one of the two protocols: classical management with chest-tube insertion (classical group, n = 33), or conservative use of chest-tube insertion (conservative group, n = 32), with drainage indicated only in the case of voluminous pleural effusion defined by a mediastinal shift and respiratory distress and/or an uncontrolled septic situation. The two groups were comparable with regard to age, baseline C-reactive protein (CRP) value and white blood cell counts, pleural thickness, identified bacteria, and antibiotic treatment. Chest-tube insertion was performed in 17 patients (52%) of the classical group compared to eight patients (25%) of the conservative group (P = 0.03). Duration of temperature above 39 degrees C was shorter in the conservative group (10 +/- 1 vs. 14 +/- 1 days, P = 0.01), as was the normalization of CRP (13 +/- 1 vs. 17 +/- 1 days, P = 0.03). Duration of hospitalization and intravenous (IV) antibiotherapy as well as the delay of chest-radiograph normalization was not significantly different between the two groups. A more conservative use of chest-tube insertion did not change short- and long-term outcome of the pleural infection in children. Drainage could be restricted to the most severely affected patients with pleural empyema causing a mediastinal shift and respiratory distress and/or presenting with an uncontrolled septic situation.

[Diseases of the pulmonary lymphatic system in children]

Diseases of the lymphatic system in children include a group of exceptional conditions difficult to manage. The anatomy of lymphatic system is complex in the lung. Variable from one subject to another, its complex physiology plays an important role in air-blood exchanges occurring in the lung. In the pulmonary interstitium and in the pleura, the lymphatic system acts like an overflow valve capable of regulating variations in interstitial fluid. The presence or development of dysplasic lymphatics causes leakage, dilatation, and reflux of the lymph through incontinent valves leading to chylothorax and/or fluid overload in the pulmonary interstitium. Symptomatic care is usually proposed, based on a fat-free diet supplemented with light-chain triglycerides and liposoluble vitamins. Other therapeutic options can be proposed. Medical options include cytotoxic agents, somatostatin, and interferon-alpha. Surgery may also be useful, but an assessment of therapeutic efficacy is very difficult due to partial effects and the small number of cases studied.

Bacterial killing is enhanced by expression of lysozyme in the lungs of transgenic mice

To assess the role of lysozyme in pulmonary host defense in vivo, transgenic mice expressing rat lysozyme cDNA in distal respiratory epithelial cells were generated. Two transgenic mouse lines were established in which the level of lysozyme protein in bronchoalveolar (BAL) lavage fluid was increased 2- or 4-fold relative to that in WT mice. Lung structure and cellular composition of BAL were not altered by the expression of lysozyme. Lysozyme activity in BAL was significantly increased (6.6- and 17-fold) in 5-wk-old animals from each transgenic line. To determine whether killing of bacteria was enhanced by expression of rat lysozyme, 5-wk-old transgenic mice and WT littermates were infected with 10(6) CFU of group B streptococci or 10(7) CFU of a mucoid strain of Pseudomonas aeruginosa by intratracheal injection. Killing of group B streptococci was significantly enhanced (2- and 3-fold) in the mouse transgenic lines at 6 h postinfection and was accompanied by a decrease in systemic dissemination of pathogen. Killing of Pseudomonas aeruginosa was also enhanced in the transgenic lines (5- and 30-fold). Twenty-four hours after administration of Pseudomonas aeruginosa, all transgenic mice survived, whereas 20% of the WT mice died. Increased production of lysozyme in respiratory epithelial cells of transgenic mice enhanced bacterial killing in the lung in vivo, and was associated with decreased systemic dissemination of pathogen and increased survival following infection.

[Penicillin-resistant pneumococcal pneumonia (serotype p14), and coinfection with respiratory syncytial virus and Mycoplasma]

A 3-year old child was admitted for a pneumococcal pneumonia with pleural effusion, initially treated with amoxicillin and clavulanic acid. Clinical deterioration suggested a resistance to conventional antibiotics which was confirmed by bacteriological investigation. A co-infection with respiratory syncitial virus and Mycoplasma pneumoniae was associated. Under adapted antibiotherapy, the clinical course improved.

Retinoic acid-induced proliferation of lung alveolar epithelial cells is linked to p21(CIP1) downregulation

Retinoids, including retinol and retinoic acid (RA) derivatives, have been shown to be involved in the processes of lung development as well as of lung repair after injury. Recently, we have provided evidence that RA could stimulate proliferation of lung alveolar type 2 epithelial cells (E. Nabeyrat, V. Besnard, S. Corroyer, V. Cazals, and A. Clement. Am. J. Physiol. Lung Cell. Mol. Physiol. 275: L71-L79, 1998). To gain some insight into the mechanisms involved in the mitogenic action of RA, we focused in the present study on the effects of RA on the expression of G(1) phase cyclins and their cell cycle-dependent kinases (Cdks). Experiments were performed with serum-deprived cells cultured in the absence and presence of RA. The results showed no effects of RA on the expression of either cyclins or Cdks. In contrast, RA treatment was found to prevent the decrease in cyclin E-Cdk2 activity observed when cells were growth arrested by serum deprivation. The observation that changes in cyclin E-Cdk2 activity were not associated with modifications in the amount of complexes formed led to the suggestion that the Cdk inhibitory protein (CKI) was involved. Study of the CKI p21(CIP1) revealed marked differences in its expression in the absence and presence of RA, with a dramatic downregulation observed in RA-treated cells. Interestingly, immunoprecipitation experiments provided evidence that the decreased levels of p21(CIP1) were associated with a reduced interaction of this CKI with cyclin E-Cdk2 complexes. These data together with previous results obtained in various situations of type 2 cell growth arrest emphasize the role of p21(CIP1) in the control of lung alveolar epithelial cell proliferation.