Impact of polymorphism of Multidrug Resistance-associated Protein 1 (ABCC1) gene on the severity of cystic fibrosis.

A 5'FR/G-260C (NCBI reference: 010393.16:g.15983174C>G) functional polymorphism of Multidrug Resistance-associated Protein 1 (ABCC1) promoter has been reported which influences ABCC1 expression including inflammatory related events. We aimed at investigating the impact of this polymorphism on the severity of CF disease. In this multicentric study, key clinical features of 203 CF patients homozygous for the F508del mutation were recorded. Kaplan-Meier analysis showed that patients with the rare CC genotype were chronically colonized by PA around 6 years earlier (mean ± SD: 11.2 year ± 7.8, 95% CI for the mean: 5.7-16.8) than those with the GG or the CG alleles (p<=0.01) and a FEV1 <60% predicted was first observed earlier in this group (p<0.05). Concordant trends to better nutritional status and FEV1 were observed in the slightly older GG subgroup. The potential role of ABCC1 promoter as a modifier gene deserves further study.

Clinical phenotype and genotype of children with borderline sweat test and abnormal nasal epithelial chloride transport.

RATIONALE: The diagnosis of cystic fibrosis (CF) is based on a characteristic clinical picture in association with a sweat chloride (Cl(-)) concentration greater than 60 mmol/L or the identification of two CF-causing mutations. A challenging problem is the significant number of children for whom no definitive diagnosis is possible because they present with symptoms suggestive of CF, a sweat chloride level in the intermediate range between 30 and 60 mmol/L, and only one or no identified CF-causing mutation. OBJECTIVES: To investigate the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the airways of children with intermediate sweat tests and inconclusive genetic findings in correlation with clinical phenotype and genotype. METHODS: We developed a composite nasal potential difference (NPD) diagnostic score to discriminate patients with CF from non-CF patients. We tested NPD in 50 children (age, 6 mo to 18 yr) with equivocal diagnoses and correlated the NPD diagnostic score with clinical phenotypes and genotypes. MEASUREMENTS AND MAIN RESULTS: Fifteen of the 50 children had NPD scores in the CF range. Eight of the 15 carried two CFTR mutations compared with only 5 of the 35 children with normal NPD scores (P = 0.01). They were significantly younger at evaluation and had recurrent lower respiratory tract infections, chronic productive coughs, and chronic Staphylococcus aureus colonization significantly more often than the 35 children with normal NPD results. CONCLUSIONS: Evaluation of CFTR function in the nasal epithelium of children with inconclusive CF diagnoses can be a useful diagnostic tool and help clinicians to individualize therapeutic strategy.

Measurement of nasal potential difference in young children with an equivocal sweat test following newborn screening for cystic fibrosis.

BACKGROUND: A challenging problem arising from cystic fibrosis (CF) newborn screening is the significant number of infants with hypertrypsinaemia (HIRT) with sweat chloride levels in the intermediate range and only one or no identified CF-causing mutations. OBJECTIVES: To investigate the diagnostic value for CF of assessing CF transmembrane conductance regulator (CFTR) protein function by measuring nasal potential difference in children with HIRT. METHODS: A specially designed protocol was used to assess nasal potential difference (NPD) in 23 young children with HIRT (3 months-4 years) with inconclusive neonatal screening. Results were analysed with a composite score including CFTR-dependent sodium and chloride secretion. Results were correlated with genotype after extensive genetic screening and with clinical phenotype at follow-up 3 years later. RESULTS: NPD was interpretable for 21 children with HIRT: 13 had NPD composite scores in the CF range. All 13 were finally found to carry two CFTR mutations. At follow-up, nine had developed a chronic pulmonary disease consistent with a CF diagnosis. The sweat test could be repeated in nine children, and six had sweat chloride values >or=60 mmol/l. Of the eight children with normal NPD scores, only two had two CFTR mutations, both wide-spectrum mutations. None had developed a CF-like lung disease at follow-up. The sweat test could be reassessed in five of these eight children and all had sweat chloride values <60 mmol/l. CF diagnosis was ruled out in six of these eight children. CONCLUSION: Evaluation of CFTR function in the nasal epithelium of young children with inconclusive results at CF newborn screening is a useful diagnostic tool for CF.

In cystic fibrosis homozygotes and heterozygotes, neutrophil apoptosis is delayed and modulated by diamide or roscovitine: evidence for an innate neutrophil disturbance.

Cystic fibrosis (CF) is a chronic inflammatory lung disease characterized by polymorphonuclear neutrophil (PMN)-dominated airway inflammation. Defective apoptosis might explain PMN persistence at these inflammation sites. We previously reported that in CF patients PMN underwent delayed apoptosis, which was not always related to their infectious state and independent of the type of CF transmembrane regulator (CFTR) mutation. To understand the role of infection and PMN apoptosis in CF, PMN apoptosis was investigated in CF parents who are obligate heterozygotes for the CFTR mutation but without chronic bacterial infection. They also demonstrated delayed PMN apoptosis compared with healthy controls, as assessed by annexin-V labeling and caspase-3 cleavage. Diamide, a direct thiol-oxidizing agent, potentiated PMN apoptosis in controls and CF patients, resulting in similar levels of constitutive and Fas-potentiated apoptosis. The cyclin-dependent kinase inhibitor roscovitine provided another approach to restore normal PMN apoptosis. However, the selective CFTR inhibitor CFTR(Inh172) did not affect PMN apoptosis in control subjects. Apparently, the dysregulation of CF PMN is not only a consequence of the chronic infectious state in CF children but might also be related to CF 'intrinsic' factors. Restoration of normal PMN apoptosis by cellular redox modulation or roscovitine opens new research avenues to decrease PMN-mediated inflammation in CF.

Feasibility and efficacy of chronic transfusion for stroke prevention in children with sickle cell disease.

OBJECTIVES: In children with sickle cell disease (SCD), chronic transfusion to maintain haemoglobin S (HbS) below 30% markedly decreases both the risk of a first stroke when transcranial Doppler (TCD) ultrasonography shows abnormal cerebral blood flow velocities and the risk of recurrent stroke. Maintaining HbS below 30% may be difficult, especially in countries where blood donors and recipients belong to different ethnic groups and where the availability of closely matched blood products is limited. We assessed the feasibility and efficacy of chronic transfusion with an HbS target of 30% in children with SCD living in the Paris area. METHODS: We retrospectively studied 29 children aged 6.8 +/- 3.0 yr (3-15 yr) at inclusion who received chronic transfusion either because of abnormal TCD findings (primary prevention group, PPG, n = 17) or because of a previous cerebrovascular event (secondary prevention group, SPG, n = 12 including nine with a history of stroke and three of transient ischaemic attacks). RESULTS: Mean follow-up was 3.5 +/- 3.0 yr (0.5-12 yr). No cases of stroke occurred in the PPG. In the SPG, one patient with a history of stroke and severe cerebrovascular disease had a recurrence after 11 yr of chronic transfusion, when the HbS level was 20%. The stroke recurrence rate (SPG group) was 1.6/100 patient-years. Mean HbS levels before and after transfusion were 30 +/- 10% and 20.6 +/- 7%, respectively. Two patients acquired red-cell alloantibodies. Of the 29 patients, 22 required iron chelation. CONCLUSIONS: Regular transfusion maintaining HbS below 30% is feasible and safe in children with SCD in France and protects from overt stroke.

Effect of mutator P. aeruginosa on antibiotic resistance acquisition and respiratory function in cystic fibrosis.

BACKGROUND: Cystic fibrosis patients suffer from recurrent bacterial infections that result in progressive deterioration of their respiratory function. Despite intensive antibiotic treatment, Pseudomonas aeruginosa is the main cause of such infections, with clones progressively developing multiple antibiotic resistance. We determined the relationship between the presence of P. aeruginosa mutator strains and cystic fibrosis clinical characteristics. METHODS: We analyzed 136 strains of P. aeruginosa isolated from the expectorations of 36 CF patients. On all strains, mutation frequencies were determined by the mutation rate to rifampicin, and antibiotic susceptibility was determined by the disk diffusion method. The epidemiological relatedness of these 136 P. aeruginosa strains was studied by pulsed-field gel electrophoresis. The appearance of new antibiotic resistance by sequential analysis of genotypically identical strains was determined. Lung function test results, that is, forced expiratory volume in 1 sec and vital capacity, were also recorded from these patients. RESULTS: We showed that bacteria with an enhanced mutation rate increase the rate of acquisition of new antibiotic resistance threefold and are associated with the deterioration of lung function. CONCLUSIONS: This study demonstrates the effect of mutator bacteria on the efficiency of patient treatment and on their respiratory function. Given the consequence of antibiotic treatment failure and lung deterioration on the prognosis of CF patients, antibiotic treatment strategies may need to be optimized to prevent the emergence of mutator clones.

Coronin-1 is associated with neutrophil survival and is cleaved during apoptosis: potential implication in neutrophils from cystic fibrosis patients.

Because neutrophil apoptosis plays a key role in resolving inflammation, identification of proteins regulating neutrophil survival should provide new strategies to modulate inflammation. Using a proteomic approach, coronin-1 was identified as a cytosolic protein cleaved during neutrophil apoptosis. Coronin-1 is an actin-binding protein that can associate with phagosomes and NADPH oxidase, but its involvement in apoptosis was currently unknown. In coronin-1-transfected PLB985 cells, coronin-1 overexpression did not modify the kinetics of granulocyte differentiation as assessed by CD11b labeling. Concerning apoptosis, increased coronin-1 expression in dimethylformamide-differentiated PLB985 significantly decreased gliotoxin-induced mitochondrial depolarization as compared with controls. Likewise, coronin-1 significantly decreased TRAIL-induced apoptosis with less mitochondrial depolarization, caspase-3 and caspase-9 activities, but not caspase-8 or Bid truncation suggesting that coronin-1 interfered with mitochondria-related events. To validate the prosurvival role of coronin-1 in a pathophysiological condition involving neutrophil-dominated inflammation, neutrophils from cystic fibrosis (CF) patients were studied. Circulating neutrophils from CF patients had more coronin-1 expression assessed by immunoblotting or proteomic analysis of cytosolic proteins. This was associated with a lower apoptosis rate than those from controls evidenced by delayed phosphatidylserine externalization and mitochondria depolarization. In addition, inflammatory neutrophils from CF patients lungs showed an intense coronin-1 immunolabeling. We concluded that coronin-1 could constitute a potential target in resolving inflammation.

Pain in children and adults with cystic fibrosis: a comparative study.

Pain is a potential complication of cystic fibrosis (CF), but its consequences in daily life and other issues of pain management are not yet clearly understood. We undertook a comparative study of children and adults with CF to assess the prevalence of pain symptoms, their characteristics and treatment, their impact on daily quality of life, and the occurrence of procedural pain. The study included 73 children (1-18 years) and 110 adults (18-52 years); 59% of the children and 89% of the adults reported at least one episode of pain during the previous month. Pain was significantly more intense and lasted significantly longer among adults, but its rate and recurrence did not differ significantly between the two populations and were not related to the severity of CF. The most prevalent locations were the abdomen for children, and the back, head, and chest for adults. Although pain significantly limited physical activity, only 15% of patients reported that it caused absenteeism, and 27% reported that it negatively affected their family life. The mean pain intensity rates on a visual analog scale for the episode that had caused the greatest pain during the past month were 4.9 (2) (mean [SD]) for children and 6 (2) for adults; however, only 40% and 50%, respectively, of those with pain reported the use of analgesic treatment, mainly paracetamol (acetaminophen). At least one episode of procedural pain during the previous month was reported by 85% of children and 78% of adults. Our study demonstrates the high incidence of undertreated pain in CF patients throughout their lives.

Does regular blood transfusion prevent progression of cerebrovascular lesions in children with sickle cell disease?

A retrospective study was conducted to assess changes in cerebrovascular lesions, as assessed by magnetic resonance (MR) imaging and angiography in 18 children with sickle cell disease (SCD) receiving optimised chronic transfusions for primary stroke prevention (abnormal transcranial Doppler flow, nine patients, median follow-up 14.3 months (range, 7.9-48.9)) or secondary stroke prevention (nine patients, median follow-up 59.6 months (range, 11.0-127.9)). An experienced neuroradiologist blinded to patient data reviewed the 41 MR scans (median/patient, three (2-4)). Standard scores were used to evaluate parenchymal and vascular abnormalities at baseline and last follow-up. Within-patient score changes evaluated using Wilcoxon's paired rank test indicated lesion progression in the secondary-prevention group (p = 0.027). Optimised transfusion therapy does not prevent progression of cerebral vasculopathy in SCD children with a history of stroke.

Glutathione S-transferases related to P. aeruginosa lung infection in cystic fibrosis children: preliminary study.

OBJECTIVES: In cystic fibrosis (CF) children, we investigated the predictive impact of glutathione S-transferases (GST) activity and genotypes P1, M1 and T1, and antioxidant levels on stage-severity of Pseudomonas aeruginosa lung infection. METHODS: GST activity was determined in whole blood by spectrophotometry, and GST genotypes by multiplex PCR RFLP for 36 CF and 9 control children. Levels of glutathione in erythrocyte and vitamins A, E and C in plasma were measured by HPLC. RESULTS: No difference in GST activity and no relationship between GST activity and antioxidant levels were observed in CF children as compared to controls. However, GST activity was lower in CF children with severe clinical status and infection, and the frequency of GSTP1 wild type genotype AA, prevalent in uninfected CF children (75%), decreased in infected ones (33%). CONCLUSION: GST activity and genotype could play an important role in modulating P. aeruginosa lung infection in CF patients.

Bacterial contamination in the environment of hospitalised children with cystic fibrosis.

Pathogenic bacterial colonisation in Cystic Fibrosis patients is associated with a poor prognosis; thus, protective measures need to be taken to prevent their transmission. We studied the extent of contamination in the environment of hospitalised children with cystic fibrosis (CF) associated with specific activities. We assessed the levels of bacterial contamination in 432 air and surface samples collected from various locations in our CF centre over a three-month period: the bedrooms, corridor, communal showers, school, leisure centre and the respiratory functional explorations (RFE) unit. Staphylococcus aureus and Pseudomonas aeruginosa strains found in bedrooms and the RFE were compared with those found in patient expectorations using pulsed field gel electrophoresis. In all sampling locations, there were high levels of airborne contamination just after the presence of patients or nursing staff. In the bedrooms, the amount of S. aureus or P. aeruginosa in the air, at wake-up and after physiotherapy, were significantly higher than that after the bedroom had been cleaned. For P. aeruginosa, 33% of isolates were multiresistant to antibiotics; 50% of the colonised patients had the same P. aeruginosa strain in their sputum as in air taken from their bedroom. P. aeruginosa was detected in 23% of samples taken from the surfaces in the showers after patient washing. Very low levels of pathogenic bacteria were found in samples from the other locations. Overall, activities with the highest risk of contamination in the CF ward are physiotherapy and washing in the communal shower room. We therefore recommend to open windows after physiotherapy and to implement a strong decontamination after showers.

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.

Efficacy, safety, and local pharmacokinetics of highly concentrated nebulized tobramycin in patients with cystic fibrosis colonized with Pseudomonas aeruginosa.

BACKGROUND AND AIM: Progressive respiratory failure due to Pseudomonas aeruginosa colonization is the most significant morbidity in patients with cystic fibrosis (CF). This trial was designed to investigate the efficacy and safety of a highly concentrated (300mg/4mL) tobramycin solution for inhalation (TSI) [Bramitob] in patients with CF and P. aeruginosa infection. METHODS: Fifty-nine patients were randomized to receive a 4-week treatment with tobramycin or placebo administered twice daily via the Pari LC Plus nebulizer and Pari TurboBoy compressor, followed by a 4-week run-out phase. Pulmonary function (forced expiratory volume in 1 second [FEV(1)], forced vital capacity [FVC], and forced expiratory flow at the midportion of vital capacity [FEF(25-75%)]), P. aeruginosa susceptibility, microbiologic results, and in vitro minimum inhibitory concentration for 90% of strains (MIC(90)) were the efficacy outcome measures, while safety was monitored by the recording of adverse events, audiometry (bone conduction at 250-8,000Hz frequency), laboratory tests, physical examination and general health condition. The concentration of tobramycin attained in sputum was measured in a cohort of 21 patients. RESULTS: FEV(1) significantly increased from baseline in the tobramycin group compared with no change in the placebo group: the absolute difference between groups (intent-to-treat population) of predicted normal was 13.2% at week 2 (p = 0.002) and 13.3% at week 4 (p = 0.003). Significant differences in favor of the tobramycin group were also observed for FVC and FEF(25-75%). The microbiologic results at the end of the treatment period (P. aeruginosa-negative culture, persistence, superinfection) showed a significantly better outcome in the tobramycin group compared with placebo (p = 0.033). The effects of tobramycin on pulmonary function and microbiology were not maintained at the end of the run-out phase. Mean sputum concentrations of tobramycin after the first dose (695.6 +/- 817.0 microg/mL) were similar to those measured after the last dose (716.9 +/- 799 microg/mL) and were superior to the detected specific MIC(90). The proportion of patients with drug-related adverse events was lower in the tobramycin group and no signs of renal or auditory toxicity were observed. CONCLUSIONS: The 4-week administration of a highly concentrated TSI significantly improved pulmonary function and microbiologic outcome compared with placebo and was well tolerated. The results of this study should be confirmed in further long-term trials in larger populations.

In vitro prediction of stop-codon suppression by intravenous gentamicin in patients with cystic fibrosis: a pilot study.

BACKGROUND: Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which acts as a chloride channel activated by cyclic AMP (cAMP). The most frequent mutation found in 70% of CF patients is F508del, while premature stop mutations are found in about 10% of patients. In vitro aminoglycoside antibiotics (e.g. gentamicin) suppress nonsense mutations located in CFTR permitting translation to continue to the natural termination codon. Pharmacologic suppression of stop mutations within the CFTR may be of benefit to a significant number of patients. Our pilot study was conducted to determine whether intravenous gentamicin suppresses stop codons in CF patients and whether it has clinical benefits. METHODS: A dual gene reporter system was used to determine the gentamicin-induced readthrough level of the most frequent stop mutations within the CFTR in the French population. We investigated readthrough efficiency in response to 10 mg/kg once-daily intravenous gentamicin perfusions in patients with and without stop mutations. Respiratory function, sweat chloride concentration, nasal potential difference (NPD) and CFTR expression in nasal epithelial cells were measured at baseline and after 15 days of treatment. RESULTS: After in vitro gentamicin incubation, the readthrough efficiency for the Y122X mutation was at least five times higher than that for G542X, R1162X, and W1282X. In six of the nine patients with the Y122X mutation, CFTR immunodetection showed protein at the membrane of the nasal epithelial cells and the CFTR-dependent Cl- secretion in NPD measurements increased significantly. Respiratory status also improved in these patients, irrespective of the gentamicin sensitivity of the bacteria present in the sputum. Mean sweat chloride concentration decreased significantly and normalised in two patients. Clinical status, NPD and sweat Cl- values did not change in the Y122X patients with no protein expression, in patients with the other stop mutations investigated in vitro and those without stop mutations. CONCLUSION: Suppression of stop mutations in the CFTR gene with parenteral gentamicin can be predicted in vitro and is associated with clinical benefit and significant modification of the CFTR-mediated Cl- transport in nasal and sweat gland epithelium.

Low bone mineral density in young children with cystic fibrosis.

RATIONALE: Low bone mineral density (BMD) is a frequent problem for adult patients with cystic fibrosis (CF). Only limited information is available for young patients. OBJECTIVES: The aim of this study was to evaluate BMD of children with CF younger than 6 years. METHODS: BMD was measured at the lumbar spine (LS) after adjustment for height, sex, and pubertal status in 25 children with CF younger than 6 years, 53 prepubertal children aged 6 to 10 years, and 36 adolescents aged 11 to 18 years. Nutritional status, body composition, pulmonary disease severity, corticosteroid usage, dietary calcium, caloric intake, and vitamin D status were evaluated as potential correlates of BMD. MEASUREMENTS AND MAIN RESULTS: The mean LS z score in the youngest group was significantly lower than normal (-0.96; SEM, 0.3). It did not differ significantly from that of children aged 6 to 10 years (-0.91; SEM, 0.2) or adolescents (-1.4; SEM, 0.2). LS z score was positively correlated with fat-free mass in multiple regression analysis. LS z score was less than -1 in 34% of the patients with mild pulmonary disease and normal nutritional status. CONCLUSIONS: These data suggest that the origin of CF bone disease in early childhood may be independent of nutritional status or disease severity.

The CF-CIRC study: a French collaborative study to assess the accuracy of cystic fibrosis diagnosis in neonatal screening.

BACKGROUND: Cystic fibrosis (CF) is caused by mutations in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein, which acts as a chloride channel after activation by cyclic AMP (cAMP). Newborn screening programs for CF usually consist of an immunoreactive trypsinogen (IRT) assay, followed when IRT is elevated by testing for a panel of CF-causing mutations. Some children, however, may have persistent hypertrypsinogenemia, only one or no identified CFTR gene mutation, and sweat chloride concentrations close to normal values. In vivo demonstration of abnormal CFTR protein function would be an important diagnostic aid in this situation. Measurements of transepithelial nasal potential differences (NPD) in adults accurately characterize CFTR-related ion transport. The aim of the present study is to establish reference values for NPD measurements for healthy children and those with CF aged 3 months to 3 years, the age range of most difficult-to-diagnose patients with suspected CF. The ultimate goal of our study is to validate NPD testing as a diagnostic tool for children with borderline results in neonatal screening. METHODS/DESIGN: We adapted the standard NPD protocol for young children, designed a special catheter for them, used a slower perfusion rate, and shortened the protocol to include only measurement of basal PD, transepithelial sodium (Na+) transport in response to the Na+ channel inhibitor amiloride, and CFTR-mediated chloride (Cl-) secretion in response to isoproterenol, a beta-agonist in a Cl- free solution. The study will include 20 children with CF and 20 healthy control children. CF children will be included only if they carry 2 CF-causing mutations in the CFTR gene or have sweat chloride concentrations > 60 mEq/L or both. The healthy children will be recruited among the siblings of the CF patients, after verification that they do not carry the familial mutation. DISCUSSION: A preliminary study of 3 adult control subjects and 4 children older than 12 years with CF verified that the new protocol was well tolerated and produced NPD measurements that did not differ significantly from those obtained with the standard protocol. This preliminary study will provide a basis for interpreting NPD measurements in patients with suspected CF after neonatal screening. Earlier definitive diagnosis should alleviate parental distress and allow earlier therapeutic intervention and genetic counseling.

Myeloperoxidase promoter polymorphism -463G is associated with more severe clinical expression of cystic fibrosis pulmonary disease.

The severity of cystic fibrosis (CF) pulmonary disease is not directly related to CFTR genotype but depends upon several parameters, including neutrophil-dominated inflammation. Identification of agents modulating inflammation constitutes a relevant goal. Myeloperoxidase (MPO) is involved in both microbicidal and proinflammatory neutrophil activities. The aim of this study was to evaluate whether the -463GA MPO promoter polymorphism is linked to clinical severity of CF-associated pulmonary inflammation. This polymorphism significantly affects the level of MPO gene expression in leukocytes and the G allele is more expressing than the A allele. We show that MPO genotype significantly influences the severity of pulmonary disease in early stages, prior to the development of chronic lung infections, with GG genotype being associated with more severe CF disease. Our findings indicate that the level of MPO gene expression influences the CF pathogenesis, presumably reflecting cellular damage by MPO-generated oxidants or other activity of MPO in airway inflammation.

Primary cytomegalovirus infection, atypical Kawasaki disease, and coronary aneurysms in 2 infants.

We describe 2 infants who developed atypical Kawasaki disease and coronary aneurysms during primary cytomegalovirus infection. These observations suggest that children with coronary aneurysms and Kawasaki-like disease should be tested for cytomegalovirus. Conversely, children with unusually severe primary cytomegalovirus infection should be tested for coronary aneurysms.

Chloride transport in nasal ciliated cells of cystic fibrosis heterozygotes.

Studying subjects heterozygous for mutations of the cystic fibrosis (CF) gene may help clarify the impact on disease onset of CF transmembrane conductance regulator protein (CFTR-)-dependent chloride secretion. CFTR-mediated chloride transport was evaluated in 52 heterozygous subjects, 32 healthy control subjects, and 77 patients with CF with class I or II mutations. We measured the change in nasal potential difference in response to chloride-free isoproterenol solution for each subject and used a video-imaging fluorescent dye assay to assess the percentage of nasal ciliated cells with cAMP-dependent anion conductance. Our findings did not confirm the standard assumption that heterozygosity implies 50% of normal CFTR function. Half the heterozygous subjects had CFTR-mediated chloride transport levels below 50% of the normal range, and one-third had levels similar to those of the patients with CF. This reduced CFTR function was not associated with an elevated prevalence of CF-like symptoms in heterozygous subjects but was highly related to respiratory status in the patients with CF. These data suggest that CFTR-dependent chloride conductance does not directly modulate disease severity but may be part of a more global defect in patients with CF involving other CFTR functions or currently unknown modulatory factors.