Jacques de Blic

Early and prolonged intravenous immunoglobulin replacement therapy in childhood agammaglobulinemia: A retrospective survey of 31 patients☆☆☆

OBJECTIVE To evaluate the outcome of children who received prolonged intravenous immunoglobulin (IVIg) replacement therapy early in life for X-linked agammaglobulinemia (XLA). STUDY DESIGN We performed a retrospective study of the clinical features and outcome of patients with genetic and/or immunologic results consistent with XLA. Patients receiving IVIg replacement therapy within 3 months of the diagnosis and for at least 4 years between 1982 and 1997 were included. RESULTS Thirty-one patients began receiving IVIg replacement therapy at a median age of 24 months and were followed up for a median time of 123 months. IVIg was given at doses >0.25 g/kg every 3 weeks, and mean individual residual IgG levels ranged from 500 to 1140 mg/dL (median, 700 mg/dL). During IVIg replacement, the incidence of bacterial infections requiring hospitalization fell from 0.40 to 0.06 per patient per year (P <. 001). However, viral or unidentified infections still developed, including enteroviral meningoencephalitis (n = 3) causing death in one patient, exudative enteropathy (n = 3), and aseptic arthritis (n = 1). At last follow-up, 30 patients were alive at a median age of 144 months (range, 58 to 253 months). Among 23 patients who were evaluated by respiratory function tests and computed tomography, 3 had an obstructive syndrome, 6 had bronchiectasis, and 20 had chronic sinusitis. CONCLUSION Early IVIg replacement therapy achieving residual IgG levels >500 mg/dL is effective in preventing severe acute bacterial infections and pulmonary insufficiency. More intensive therapy may be required to fully prevent the onset of bronchiectasis, chronic sinusitis, and nonbacterial infections, particularly enteroviral infections, in all cases.

CCDC39 is required for assembly of inner dynein arms and the dynein regulatory complex and for normal ciliary motility in humans and dogs

Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by recurrent infections of the upper and lower respiratory tract, reduced fertility in males and situs inversus in about 50% of affected individuals (Kartagener syndrome). It is caused by motility defects in the respiratory cilia that are responsible for airway clearance, the flagella that propel sperm cells and the nodal monocilia that determine left-right asymmetry. Recessive mutations that cause PCD have been identified in genes encoding components of the outer dynein arms, radial spokes and cytoplasmic pre-assembly factors of axonemal dyneins, but these mutations account for only about 50% of cases of PCD. We exploited the unique properties of dog populations to positionally clone a new PCD gene, CCDC39. We found that loss-of-function mutations in the human ortholog underlie a substantial fraction of PCD cases with axonemal disorganization and abnormal ciliary beating. Functional analyses indicated that CCDC39 localizes to ciliary axonemes and is essential for assembly of inner dynein arms and the dynein regulatory complex.

Efficacy of nebulized budesonide in treatment of severe infantile asthma: A double-blind study

BACKGROUND AND OBJECTIVE Treatments with inhaled corticosteroids yielded conflicting results in infants with severe asthma. The purpose of this study was to assess the efficacy of nebulized budesonide on the control of asthma in this age group. METHODS In a double-blind, placebo-controlled study, 40 infants with severe asthma received either nebulized budesonide (1 mg) or placebo twice daily for 12 weeks, followed by a follow-up period of up to 12 weeks. A jet nebulizer driven by an air compressor was used to administer budesonide and placebo. RESULTS Fewer patients in the budesonide group had an exacerbation during the treatment period (40%) compared with the placebo group (83%, p < 0.01). The duration of oral steroid therapy was shorter in the budesonide group than in the placebo group (median number of days of exacerbation as a proportion of the total treatment time, 0% vs 14.5%; p < 0.05). The incidence of daytime (p < 0.05) and nighttime wheezing (p < 0.01) was lower in the budesonide group than in the placebo group during the treatment period. The proportion of patients without an exacerbation of asthma during the entire 24 weeks was 28% for those patients who had received budesonide and 0% for those patients who had received placebo. Asthma improved in more patients in the budesonide group (17 and 19, 89%) than in the placebo group (7 of 16, 44%; p < 0.005). These results should improve and modify the treatment of infants with severe asthma. CONCLUSION Nebulized budesonide (1 mg twice daily) is a well-tolerated and efficient treatment for severe infantile asthma.

DC-SIGN Induction in Alveolar Macrophages Defines Privileged Target Host Cells for Mycobacteria in Patients with Tuberculosis

Background Interplays between Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB) in human and host professional phagocytes, namely macrophages (Mφs) and dendritic cells (DCs), are central to immune protection against TB and to TB pathogenesis. We and others have recently shown that the C-type lectin dendritic cell–specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN; CD209) mediates important interactions between mycobacteria and human monocyte-derived DCs (MoDCs) in vitro. Methods and Findings In order to explore the possible role of DC-SIGN in M. tuberculosis infection in vivo, we have analysed DC-SIGN expression in broncho-alveolar lavage (BAL) cells from patients with TB (n = 40) or with other non-mycobacterial lung pathologies, namely asthma (n = 14) and sarcoidosis (n = 11), as well as from control individuals (n = 9). We show that in patients with TB, up to 70% of alveolar Mφs express DC-SIGN. By contrast, the lectin is barely detected in alveolar Mφs from all other individuals. Flow cytometry, RT-PCR, and enzyme-linked immunosorbent assay analyses of BAL-derived fluids and cells indicated that M. tuberculosis infection induces DC-SIGN expression in alveolar Mφs by a mechanism that is independent of Toll-like receptor-4, interleukin (IL)-4, and IL-13. This mechanism most likely relies on the secretion of soluble host and/or mycobacterial factors that have yet to be identified, as both infected and uninfected bystander Mφs were found to express DC-SIGN in the presence of M. tuberculosis. Immunohistochemical examination of lung biopsy samples from patients with TB showed that the bacilli concentrate in pulmonary regions enriched in DC-SIGN-expressing alveolar Mφs in vivo. Ex vivo binding and inhibition of binding experiments further revealed that DC-SIGN–expressing alveolar Mφs constitute preferential target cells for M. tuberculosis, as compared to their DC-SIGN− counterparts. In contrast with what has been reported previously in MoDCs in vitro, ex vivo DC-SIGN ligation by mycobacterial products failed to induce IL-10 secretion by alveolar Mφs, and IL-10 was not detected in BALs from patients with TB. Conclusion Altogether, our results provide further evidence for an important role of DC-SIGN during TB in humans. DC-SIGN induction in alveolar Mφs may have important consequences on lung colonization by the tubercle bacillus, and on pulmonary inflammatory and immune responses in the infected host.

Microbiological Diagnosis of Empyema in Children: Comparative Evaluations by Culture, Polymerase Chain Reaction, and Pneumococcal Antigen Detection in Pleural Fluids

BACKGROUND Pleural empyema is an increasingly reported complication of pneumonia in children. Microbiological diagnostic tests for empyema by culture frequently have false-negative results due to previous administration of antibiotics. Molecular diagnosis by broad-range 16S ribosomal DNA (rDNA) polymerase chain reaction (PCR) and rapid pneumococcal antigen detection are reliable tools, but their diagnostic value has not been clearly established for pleural fluid samples. Pneumococcal antigen detection has only been validated for urine and cerebrospinal fluid samples. METHODS Over 4 years, pleural fluid specimens were collected from 78 children with pleural empyema. Standard culture, pneumococcal antigen detection by latex agglutination (Pastorex; Bio-Rad) and immunochromatographic testing (Binax NOW Streptococcus pneumoniae), and 16S rDNA PCR were performed on these specimens. Pneumococcal identification by 16S rDNA PCR and sequencing was confirmed by pneumolysin PCR. RESULTS Of the 78 cases of pleural empyema, 60 (77%) were microbiologically documented by culture or 16S rDNA PCR. Of the 40 pneumococcal empyema cases, 17 (43%) were only diagnosed by PCR and 23 with PCR and culture. The sensitivity and specificity of the latex antigen detection (with the use of culture and/or PCR as the test standard) were 90% and 95%, respectively. The immunochromatographic test detected pneumococcal antigens in 3 additional specimens for which latex agglutination results were negative, thereby increasing the sensitivity of antigen detection. CONCLUSIONS Pneumococcal antigen detection in pleural fluid specimens from children provides a rapid and sensitive method of diagnosis of pneumococcal empyema, which can be confirmed by specific pneumolysin PCR when culture results are negative. Broad-range 16S rDNA PCR has value in detecting bacterial agents responsible for culture-negative pleural empyema.

Mutation of SFTPC in infantile pulmonary alveolar proteinosis with or without fibrosing lung disease

Pulmonary surfactant protein C (SP‐C) is a highly hydrophobic peptide produced by type‐II alveolar cells through the processing of a high‐molecular weight precursor (pro‐SP‐C), that enhances surface tension and facilitates the recycling of pulmonary surfactant in vitro. Recently, two seemingly dominant‐negative mutations of the pro‐SP‐C‐encoding gene (SFTPC, MIM 178620), were reported in families with vertically‐inherited interstitial lung disease (Nogee et al. [2001: N Engl J Med 344:573–579]; Thomas et al. [2002: Am J Respir Crit Care Med 165:1322–1328]). We have examined the SP‐C protein and its precursor as well as the encoding gene, in a cohort of 34 sporadic or familial cases with unexplained respiratory distress (URD) in which surfactant protein B (SP‐B) deficiency related to SFTPB mutation had been ruled out. One patient with complete SP‐C deficiency had no detectable mutation of SFTPC. Of the 10 patients with abnormal pro‐SP‐C processing, as suggested from analysis of broncho‐alveolar lavage (BAL) fluid, two distinct heterozygous SFTPC missense mutations were identified. The first, g.1286T > C (p.I73T), was de novo and resulted in progressive respiratory failure with intra‐alveolar storage of a granular, protein‐ and lipid‐rich, periodic acid Schiff (PAS)‐positive material (pulmonary alveolar proteinosis (PAP)), and interstitial lung disease. The second, g.2125G > A (p.R167Q), was found in two PAP patients from the endogamous white settler population of Réunion Island in which URD has an unexpectedly high prevalence. Since this mutation was diagnosed in subjects from this subpopulation who did not have evidence for lung disease, we propose environmental exposures or modifier genes to play a role in the phenotype, as suggested from murine models lacking the SP‐C protein, although we cannot rule out a rare polymorphism, hitherto restricted to that subpopulation. Most remarkably, these observations extend the phenotypic spectrum related to SFTPC mutation from interstitial lung disease to PAP. Notably, the reported mutations do not appear to be dominant negatives. This article contains supplementary material, which may be viewed at the American Journal of Medical Genetics website at http://www.interscience.wiley.com/jpages/0148‐7299/suppmat/index.html.

Glucose tolerance and insulin secretion, morbidity, and death in patients with cystic fibrosis.

OBJECTIVES To describe the history, mechanisms, and consequences of cystic fibrosis (CF)-related diabetes, from childhood to early adulthood. STUDY DESIGN Pancreatic beta-cell function was estimated from the plasma insulin/glucose ratios during oral glucose tolerance test (total area under the curve and deltaI(30-0min)/G(30min), homeostasis model assessment [HOMA]%B), insulin sensitivity with the HOMA%S index, in 237 children with CF (109 boys, 128 girls). Progression of glucose metabolism abnormalities was evaluated by analysis for interval censored data; rates of pulmonary transplantation and death by Kaplan-Meier analysis. RESULTS Impaired glucose tolerance was found in 20% of patients at 10 years, 50% at 15 years, 75% at 20 years, 82% at 30 years; for diabetes, >20% at 15 year, 45% at 20 years, 70% at 30 years; for insulin treatment, 30% at 20 years, 40% at 30 years. Early impairment was associated with lower survival rates and higher rates of lung transplantation. The area under the curve(glucose) correlated with decreased body mass index and height. Decrease in early insulin secretion (deltaI(30-0min)/G(30min)) was associated with impaired glucose tolerance, in all estimates of insulin secretion with diabetes. HOMA%S did not differ between the groups. Increased inflammation correlated with insulin resistance and impaired glucose tolerance. CONCLUSIONS CF-related diabetes, mainly because of beta-cell deficiency, is frequent early in life and associated with impaired nutritional state and growth, increased rates of terminal respiratory failure, and death.

Loss-of-Function Mutations in the Human Ortholog of Chlamydomonas reinhardtii ODA7 Disrupt Dynein Arm Assembly and Cause Primary Ciliary Dyskinesia

Cilia and flagella are evolutionarily conserved structures that play various physiological roles in diverse cell types. Defects in motile cilia result in primary ciliary dyskinesia (PCD), the most prominent ciliopathy, characterized by the association of respiratory symptoms, male infertility, and, in nearly 50% of cases, situs inversus. So far, most identified disease-causing mutations involve genes encoding various ciliary components, such those belonging to the dynein arms that are essential for ciliary motion. Following a candidate-gene approach based on data from a mutant strain of the biflagellated alga Chlamydomonas reinhardtii carrying an ODA7 defect, we identified four families with a PCD phenotype characterized by the absence of both dynein arms and loss-of-function mutations in the human orthologous gene called LRRC50. Functional analyses performed in Chlamydomonas reinhardtii and in another flagellated protist, Trypanosoma brucei, support a key role for LRRC50, a member of the leucine-rich-repeat superfamily, in cytoplasmic preassembly of dynein arms.

Loss-of-Function Mutations in LRRC6, a Gene Essential for Proper Axonemal Assembly of Inner and Outer Dynein Arms, Cause Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a group of autosomal-recessive disorders resulting from cilia and sperm-flagella defects, which lead to respiratory infections and male infertility. Most implicated genes encode structural proteins that participate in the composition of axonemal components, such as dynein arms (DAs), that are essential for ciliary and flagellar movements; they explain the pathology in fewer than half of the affected individuals. We undertook this study to further understand the pathogenesis of PCD due to the absence of both DAs. We identified, via homozygosity mapping, an early frameshift in LRRC6, a gene that encodes a leucine-rich-repeat (LRR)-containing protein. Subsequent analyses of this gene mainly expressed in testis and respiratory cells identified biallelic mutations in several independent individuals. The situs inversus observed in two of them supports a key role for LRRC6 in embryonic nodal cilia. Study of native LRRC6 in airway epithelial cells revealed that it localizes to the cytoplasm and within cilia, whereas it is absent from cells with loss-of-function mutations, in which DA protein markers are also missing. These results are consistent with the transmission-electron-microscopy data showing the absence of both DAs in cilia or flagella from individuals with LRRC6 mutations. In spite of structural and functional similarities between LRRC6 and DNAAF1, another LRR-containing protein involved in the same PCD phenotype, the two proteins are not redundant. The evolutionarily conserved LRRC6, therefore, emerges as an additional player in DA assembly, a process that is essential for proper axoneme building and that appears to be much more complex than was previously thought.

Allergy to β-Lactam Antibiotics in Children

Background. Skin tests with soluble β-lactams can be used to diagnose immediate and delayed hypersensitivity (HS) reactions to β-lactam antibiotics. Very few studies have been performed with children with suspected β-lactam allergy. In these studies, immediate HS to β-lactams was diagnosed by skin tests in 4.9% to 40% of children. The diagnostic and predictive values of immediate responses in skin tests are good, because very few children with negative skin test results have positive oral challenge (OC) test results. Delayed responses in skin tests (intradermal and patch tests) have been reported in adult patients and children suffering with urticaria, angioedema, and maculopapular rashes during treatments with β-lactam antibiotics. However, the diagnostic and predictive values of late responses are unknown. Semi-late responses in skin tests with β-lactams have never been studied in adults or children. Objectives. The aims of this study were to confirm or rule out the diagnosis of allergy to β-lactams in children with histories of adverse reactions to these antibiotics, to determine whether allergic children were sensitized to one or several classes of β-lactams, and to evaluate the frequency and diagnostic value of immediate, accelerated, and delayed responses in skin tests with β-lactam antibiotics in children. Methods. We studied 325 children with suspected β-lactam allergy. Skin tests (prick and intradermal) were performed with soluble forms of the suspected (or very similar) β-lactams and with one or several β-lactams from other classes. The reaction was assessed after 20 minutes (immediate), 8 hours (accelerated), and 48 to 72 hours (delayed). OCs with the suspected β-lactams were performed in patients with negative skin test results, except those with severe serum sickness-like reactions and potentially harmful toxidermias. Results. Skin tests and OCs led to the diagnosis of β-lactam allergy in 24 (7.4%) and 15 (4.6%) of the children, respectively. Thus, only 12% of the children were diagnosed as allergic to β-lactams by means of skin tests and OC. HS to β-lactams was suspected from clinical history in 30 (9.2%) children reporting serum sickness-like reactions and potentially harmful toxidermias. In a few children, we diagnosed food allergy and intolerance to excipients or nonsteroidal antiinflammatory drugs. No cause was found in the other children. Based on skin tests and OC, the prevalences of immunoglobulin E-dependent and of semi-late or delayed sensitizations to β-lactam assessed were similar (6.8% vs 5.2%, respectively). Most immunoglobulin E-dependent sensitizations were diagnosed by means of skin tests (86.4%). In contrast, most semi-late and delayed sensitizations were diagnosed by OC (70.6%). The likelihood of β-lactam allergy was significantly higher for anaphylaxis (42.9% vs 8.3% in other reactions) and immediate reactions (25% vs 10% in accelerated and delayed reactions). Of the children diagnosed as allergic to β-lactam by means of skin tests, OC, and clinical history, 11.7% were sensitized to several classes of β-lactams. The risk was significantly higher in children with anaphylaxis (26.7% vs 7.5% of the children with other reactions) and in children reporting immediate reactions (33.3% vs 8.5% of the children with accelerated and delayed reactions). Finally, age, sex, personal history of atopy, number of reactions to β-lactams, and number of reactions to other drugs were not significant risk factors for β-lactam allergy. Conclusion. The skin tests were safe, and the immediate reaction to skin tests successfully diagnosed allergy to β-lactam antibiotics in children reporting reactions suggestive of immediate HS. In contrast, most accelerated and delayed reactions were diagnosed by OC. Thus, our results suggest that the diagnostic and predictive values of skin tests for nonimmediate HS to β-lactams in children are low. They also strongly suggest that most reactions reported in children are attributable to infectious diseases or interactions between drugs and infectious agents rather than to β-lactam HS. β-lactams, allergy, skin tests, oral challenge, child.