Paternal isodisomy of chromosome 7 with cystic fibrosis and overgrowth

We have diagnosed a boy with cystic fibrosis (CF) due to paternal UPD presenting with overweight and developmental delay, not typical features to CF patients. Two previously reported patients with paternal UPD(7) did not present overgrowth. The discrepancy between the phenotype of this boy and the other two patients raises the question of imprinted genes or homozygotization of a disease-causing gene in paternal UPD7.

Nontuberculous mycobacteria in cystic fibrosis associated with allergic bronchopulmonary aspergillosis and steroid therapy

Nontuberculous mycobacterial (NTM) infection, particularly due to Mycobacterium abscessus, is an emerging disease that can be relentlessly progressive, particularly in cystic fibrosis (CF) patients. The risk factors that were associated with this increasingly symptomatic infection in a group of CF patients were investigated. A total of 139 CF patients aged 2-52 yrs were reviewed. Sputum was cultured for NTM annually or whenever clinical deterioration was unexplained. In total, 12 patients (8.6%) had positive cultures and six (4.3%) met the criteria for NTM pulmonary disease (five with M. abscessus). Five had allergic bronchopulmonary aspergillosis (ABPA) compared with one out of 133 patients without NTM disease. Five had received systemic steroids (four as a treatment for ABPA) compared with only one out of 133 without NTM lung disease. All six NTM patients deteriorated markedly following mycobacterial infection, and forced expiratory volume in one second dropped 18-46%. Despite prolonged triple antibiotic therapy, M. abscessus was not eradicated, and four out of six did not return to baseline clinically. In conclusion, severe nontuberculous mycobacterial lung disease, particularly with Mycobacterium abscessus, is becoming a perplexing challenge in cystic fibrosis patients. Allergic bronchopulmonary aspergillosis and systemic steroids appear to be risk factors, although small patient numbers limit this to a descriptive observation. When pulmonary condition deteriorates, increased surveillance for mycobacteria would enable prompt diagnosis and treatment.

Trampoline use as physiotherapy for cystic fibrosis patients

Physicians and physiotherapists who care for CF patients have recommended the use of trampolines as a physiotherapeutic tool for enhancing cardiopulmonary performance, encouraging sputum production, and improving general well-being. Despite some therapeutic and recreational benefits associated with trampoline use, papers in the general pediatric population mostly document an increased incidence of injuries, ranging from minor trauma to spinal cord injuries and even death. The aim of this review is to examine the accumulated published data regarding the use of trampolines, to assess their potential contributions and disadvantages for CF patients, and to define whether trampoline use should be recommended. An extensive search in the published medical literature retrieved approximately 60 articles that primarily dealt with trampolines, out of which only two dealt with CF. The preponderance of these articles are reports pertaining to injuries related to the use of trampolines, with only a few describing the medical, physiologic, and/or psychological benefits of trampolines. Based on the accumulated data, the presumed benefits of trampoline use for CF patients are not proven. Furthermore, the suggested benefits could be acquired using other types of exercise. Weighing the known risks of trampolines against the potential benefits that are not unique to this modality suggests that the use of trampolines for CF should not be recommended.

Familial concordance of phenotype and microbial variation among siblings with CF

The clinical spectrum of cystic fibrosis (CF) is influenced by the cystic fibrosis transmembrane conductance regulator (CFTR) genotype. However, variable courses of the disease were demonstrated among patients with identical genotypes. Since siblings share identical CFTR mutations and environmental factors, they can serve as a model to assess the effect of modifier genes on disease expression, and also to evaluate cross-infection. The aim of this study was to compare disease expression among siblings with CF. All sibling pairs treated at 7 CF centers in Israel were included in the study. Data were collected from patients' medical charts. Fifty families with at least 2 siblings were identified. As expected, the second-born sibling was diagnosed at an earlier age compared to the first-born. The mode of CF presentation at diagnosis showed significant familial concordance. In the families where the first sibling presented with gastrointestinal manifestations, 79% of the second siblings also presented with gastrointestinal manifestations. When gastrointestinal manifestations were absent in the first sibling, only 12% of the second siblings presented with gastrointestinal manifestations (P < 0.0001). Likewise, when the first sibling presented with respiratory symptoms, 60% of the second siblings presented with the similar symptoms. However, when the first sibling presented without respiratory symptoms, only 12% of the second siblings presented with respiratory symptoms (P < 0.001). Meconium ileus (MI) was present in 20 patients (21%). In 10 families where the first-born sibling had MI, 8 (80%) of the subsequent siblings had MI. On the other hand, in the 39 families where the first-born sibling did not have MI, only 2 (5%) subsequent siblings had MI (P < 0.001). Pancreatic insufficiency (PI) also had high familial concordance (P < 0.0001). Percentile growth for weights and heights and lung function (FVC, FEV(1), and FEF(25-75)) at ages 7 and 10 years were similar between siblings. P. aeruginosa grew from sputum in 89% of our study patients. When P. aeruginosa was isolated from the first-born patient, 91% of the second siblings were also positive for P. aeruginosa, whereas when the initial sibling was not a carrier of P. aeruginosa, only 50% of subsequent siblings were positive (P < 0.0001). This familial concordance was not observed for S. aureus. By contrast, the age of first isolation of P. aeruginosa and S. aureus was significantly earlier in the second sibling than in the first for the two bacteria: 10.3 +/- 5.1 vs. 7.3 +/- 5.2 years (P < 0.05) for P. aeruginosa, and 11.5 +/- 5.4 years vs. 6.8 +/- 5.1 years (P < 0.05) for S. aureus. CF siblings tend to share similar phenotypes that are not mutation-dependent. The lack of variability between siblings in mode of initial CF presentation, rates of MI, pulmonary function, and nutritional status supports the role of modifier genes in the determination of these factors.

Role of hydrogen peroxide in sperm capacitation and acrosome reaction

The generation of reactive oxygen species (ROS) has been implicated in the regulation of sperm capacitation and acrosome reaction; however, the mechanisms underlying this regulation remain unclear. To examine the cellular processes involved, we studied the effect of different concentrations of hydrogen peroxide (H(2)O(2)) on protein tyrosine phosphorylation under various conditions. Treatment of spermatozoa with H(2)O(2) in medium without heparin caused a time- and dose-dependent increase in protein tyrosine phosphorylation of at least six proteins in which maximal effect was seen after 2 h of incubation with 50 microM H(2)O(2). At much higher concentrations of H(2)O(2) (0.5 mM), there is significant reduction in the phosphorylation level, and no protein tyrosine phosphorylation is observed at 5 mM H(2)O(2) after 4 h of incubation. Exogenous NADPH enhanced protein tyrosine phosphorylation similarly to H(2)O(2). These two agents, but not heparin, induced Ca(2+)-dependent tyrosine phosphorylation of an 80-kDa protein. Treatment with H(2)O(2) (50 microM) caused approximately a twofold increase in cAMP, which is comparable to the effect of bicarbonate, a known activator of soluble adenylyl cyclase in sperm. This report suggests that relatively low concentrations of H(2)O(2) are beneficial for sperm capacitation, but that too high a concentration inhibits this process. We also conclude that H(2)O(2) activates adenylyl cyclase to produce cAMP, leading to protein kinase A-dependent protein tyrosine phosphorylation.

Gentamicin-induced correction of CFTR function in patients with cystic fibrosis and CFTR stop mutations

BACKGROUND

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene containing a premature termination signal cause a deficiency or absence of functional chloride-channel activity. Aminoglycoside antibiotics can suppress premature termination codons, thus permitting translation to continue to the normal end of the transcript. We assessed whether topical administration of gentamicin to the nasal epithelium of patients with cystic fibrosis could result in the expression of functional CFTR channels.

METHODS

In a double-blind, placebo-controlled, crossover trial, patients with stop mutations in CFTR or patients homozygous for the DeltaF508 mutation received two drops containing gentamicin (0.3 percent, or 3 mg per milliliter) or placebo in each nostril three times daily for two consecutive periods of 14 days. Nasal potential difference was measured at base line and after each treatment period. Nasal epithelial cells were obtained before and after gentamicin treatment from patients carrying stop mutations, and the C-terminal of surface CFTR was stained.

RESULTS

Gentamicin treatment caused a significant reduction in basal potential difference in the 19 patients carrying stop mutations (from -45+/-8 to -34+/-11 mV, P=0.005) and a significant response to chloride-free isoproterenol solution (from 0+/-3.6 to -5+/-2.7 mV, P<0.001). This effect of gentamicin on nasal potential difference occurred both in patients who were homozygous for stop mutations and in those who were heterozygous, but not in patients who were homozygous for DeltaF508. After gentamicin treatment, a significant increase in peripheral and surface staining for CFTR was observed in the nasal epithelial cells of patients carrying stop mutations.

CONCLUSIONS

In patients with cystic fibrosis who have premature stop codons, gentamicin can cause translational "read through," resulting in the expression of full-length CFTR protein at the apical cell membrane, and thus can correct the typical electrophysiological abnormalities caused by CFTR dysfunction.

Serum CA 19?9 levels as a diagnostic marker in cystic fibrosis patients with borderline sweat tests

Patients with normal or borderline sweat tests present a diagnostic challenge. In spite of the availability of genetic analysis and measurement of nasal potential difference, there is still uncertainty in diagnosing cystic fibrosis in some patients. CA 19-9 is a tumor-associated antigen whose levels were previously found to be elevated in some cystic fibrosis patients. We investigated whether serum CA 19-9 levels can contribute to establishing the diagnosis of cystic fibrosis in patients with a borderline sweat test, and evaluated the influence of different clinical variables on CA 19-9 levels. Serum CA 19-9 levels were measured in 82 cystic fibrosis patients grouped according to their genotype and in 38 healthy individuals. Group A included 50 patients who carried two mutations previously found to be associated with a pathological sweat test and pancreatic insufficiency (DeltaF508, W1282X, G542X, N1303K, and S549R). Group B included 13 compound heterozygote cystic fibrosis patients who carried one mutation known to cause mild disease with a borderline or normal sweat test and pancreatic sufficiency (3849+10kb C-->T, 5T). Group C included 38 normal controls. Nineteen cystic fibrosis patients carried at least one unidentified mutation. An association between CA 19-9 levels and age, pulmonary function, pancreatic status, sweat chloride, previous pancreatitis, serum lipase, meconium ileus, distal intestinal obstruction, liver disease, and diabetes was investigated. The distribution of CA 19-9 levels was significantly different between the three groups ( p<0.01); high CA 19-9 levels were found in 60% (30/50) of group Apatients and in 46.6% (6/13) of group B patients, but in only 5.2% (2/38) of the controls. CA 19-9 levels were inversely related to forced expiratory volume in 1 s, while no association was found with the other clinical parameters examined. Our findings suggest that the serum CA 19-9 in cystic fibrosis patients originates in the respiratory system, and has a useful ancillary role, particularly when diagnostic uncertainty exists. Hence, the diagnosis of cystic fibrosis should be considered in patients with borderline sweat tests and high CA 19-9 levels, but normal levels do not exclude cystic fibrosis.

Prediction of mortality and timing of referral for lung transplantation in cystic fibrosis patients

Lung transplantation (Tx) is an optional treatment for cystic fibrosis (CF) patients with end-stage lung disease. The decision to place a patient on the Tx waiting list is frequently complex, difficult, and controversial. This study evaluated the current criteria for lung Tx and assessed additional parameters that may identify CF patients at high risk of death. Data were extracted from the medical records of 392 CF patients. Forty of these patients had a forced expiratory volume in 1 s (FEV(1)) less than 30% predicted, and nine of these 40 patients were transplanted. A comparison was performed between the survival of those transplanted (n = 9) and those not transplanted (n = 31), by means of Kaplan-Meier survival curves. The influence on survival of age, gender, nutritional status, sputum aspergillus, diabetes mellitus, recurrent hemoptysis, oxygen use, and the decline rate of FEV(1), were investigated by means of univariate and multivariate analyses. The rate of decline of FEV(1) was evaluated employing the linear regression model. CF patients with a FEV(1)< 30% and who did not receive a lung transplant had survived longer than CF patients who did receive a lung transplant (median survival 7.33 vs. 3.49 yr, 5-yr survival 73% vs. 29%). Two factors--rate of decline in FEV(1) values and age < 15 yr--were found to influence the mortality rate, while the other parameters examined did not. Our results indicate that the current criterion of FEV(1)< 30% predicted, alone is not sufficiently sensitive to predict the mortality rate in CF patients and time of referral for Tx, as many of these patients survive for long periods of time. Additional criteria to FEV(1)< 30%, should include rapidly declining FEV(1) values and age < 15 yr.

Nasal potential difference measurements in patients with atypical cystic fibrosis

The diagnosis of cystic fibrosis (CF) is based on characteristic clinical and laboratory findings. However, a subgroup of patients present with an atypical phenotype that comprises partial CF phenotype, borderline sweat tests and one or even no common cystic fibrosis transmembrane conductance regulator (CFTR) mutations. The aim of this study was to evaluate the role of nasal potential difference (PD) measurements in the diagnosis of CF patients with an atypical presentation and in a population of patients suspected to have CF. Nasal PD was measured in 162 patients from four different groups: patients with classical CF (n = 31), atypical phenotype (n = 11), controls (n = 50), and patients with questionable CF (n = 70). The parameter, or combination of nasal PD parameters was calculated in order to best discriminate all CF patients (including atypical CF) from the non-CF group. The patients with atypical CF disease had intermediate values of PD measurements between the CF and non-CF groups. The best discriminate model that assigned all atypical CF patients as CF used: e(response to chloride-free and isoproterenol/response to amiloride) with a cut-off >0.70 to predict a CF diagnosis. When this model was applied to the group of 70 patients with questionable CF, 24 patients had abnormal PD similar to the atypical CF group. These patients had higher levels of sweat chloride concentration and increased rate of CFTR mutations. Nasal potential difference is useful in diagnosis of patients with atypical cystic fibrosis. Taking into account both the sodium and chloride transport elements of the potential difference allows for better differentiation between atypical cystic fibrosis and noncystic fibrosis patients. This calculation may assist in the diagnostic work-up of patients whose diagnosis is questionable.

Serum lipase levels as a diagnostic marker in cystic fibrosis patients with normal or borderline sweat tests

Patients with normal or borderline sweat test present a diagnostic challenge. In spite of the availability of different methods such as genetic analysis and measurements of nasal potential difference, uncertainty in diagnosing cystic fibrosis (CF) in some patients still exists. Neonates with CF have high serum lipase levels, which decline over time in pancreatic-insufficient patients, whereas pancreatic-sufficient patients demonstrate high serum lipase levels beyond infancy. Because patients with borderline or normal sweat test are almost always pancreatic sufficient, this study was aimed to assess whether serum lipase levels may be of help in establishing the diagnosis of CF in these patients. Serum lipase levels were measured in 100 CF patients and in 17 healthy individuals. Patients were grouped according to their genotype. Group A patients (n = 70) carried two mutations previously found to be associated with a pathologic sweat test and pancreatic insufficiency (delta F508, W1282X, G542X, N1303K, S549R). Group B (n = 30) were compound heterozygote patients who carried one mutation known to cause mild disease with borderline or normal sweat tests and pancreatic sufficiency (3849+10kb C-->T, 5T). Group C included 17 healthy controls. Serum lipase levels ranged between 2 and 104.4 U/L (mean +/- SD 16.9 +/- 14.7), 6.1-200 U/L (mean +/- SD 53.9 +/- 47.9), and 8.5-27.8 U/L (mean +/- SD 16.9 +/- 5.1) in Groups A, B, and C, respectively, with some overlapping between groups. The distribution of lipase levels was significantly different in Group B vs Groups A and C (P < 0.01). High lipase levels were found in 63.3% (19/30) of Group B patients, but in only 4.3% (3/70) and 0% (0/17) of Group A and C, respectively. Lipase levels were found to be inversely related to sweat chloride concentrations (r = -0.19, P < 0.05). Patients with borderline or normal sweat tests had high lipase levels, whereas low lipase levels were associated with pathologic sweat tests. Our findings indicate that the serum lipase level is genetically determined and that it has a useful role in the diagnosis of CF. Thus, in patients with borderline sweat tests and high lipase levels, the diagnosis of CF should be considered.

A pilot study of the effect of gentamicin on nasal potential difference measurements in cystic fibrosis patients carrying stop mutations

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene containing a premature termination signal are expected to produce little or no CFTR chloride channels. It has been shown in vitro, that aminoglycoside antibiotics can increase the frequency of erroneous insertion of nonsense codons hence permitting the translation of CFTR alleles carrying missense mutations to continue reading to the end of the gene. This led to the appearance of functional CFTR channels at the apical plasma membrane. The aim of this research was to determine if topical application of gentamicin to the nasal epithelium of patients with cystic fibrosis (CF) carrying stop mutations can express, in vivo, functional CFTR channels. Nine CF patients carrying stop mutations (mean age 23 +/- 11 yr, range 12 to 46 yr) received gentamicin drops (0.3%, 3 mg/ml) three times daily intranasally for a total of 14 d. Nasal potential difference (PD) was measured before and after the treatment. Before gentamicin application all the patients had abnormal nasal PD typical of CF. After gentamicin treatment, significant repolarization of the nasal epithelium representing chloride transport was increased from -1 +/- 1 mV to -10 +/- 11 mV (p < 0. 001). In conclusion, gentamicin may influence the underlying chloride transport abnormality in patients with CF carrying stop mutations.

Clinical and genetic risk factors for cystic fibrosis-related liver disease

OBJECTIVE

The aim of this study was to define the role of possible risk factors for the development of cystic fibrosis (CF)-related liver disease and to analyze the association between liver disease and the different genotypes present in the Israeli CF patient population.

PATIENTS AND METHODS

All patients followed at the seven CF centers in Israel were included in this study. Liver disease was determined by persistently elevated serum liver enzymes and/or bilirubin, and/or significant ultrasonographic changes suggestive of chronic liver disease. The following clinical parameters were evaluated: ethnic origin, age at assessment of liver function, sex, history of meconium ileus, pancreatic function, history of distal intestinal obstruction syndrome, pulmonary function, and cystic fibrosis transmembrane conductance regulator mutation analysis.

RESULTS

Of the 288 patients screened, 80 (28%) had liver disease. Of the 256 patients with pancreatic insufficiency, 80 (31%) had liver disease compared with none of the 32 patients with pancreatic sufficiency. Genotype-phenotype correlation was performed on 207 patients carrying identified mutations that were previously classified according to phenotype severity. Liver disease was found in 56 (32%) of 173 patients carrying mutations associated with a severe phenotype and in 6 (38%) of 16 patients carrying at least one mutation associated with a variable genotype (G85E and/or 5T allele). None of the 18 patients carrying the 3849+10kb C->T mutation had liver disease. Prevalence of liver disease increased with age. No correlation was found between liver disease and severity of lung disease, nutritional status, history of meconium ileus, or distal intestinal obstruction syndrome.

CONCLUSION

CF patients who have pancreatic insufficiency and carry mutations associated with a severe or a variable genotype are at increased risk to develop liver disease.

Severe Clostridium difficile-associated colitis in young patients with cystic fibrosis

We report four patients with cystic fibrosis and fulminant Clostridium difficile-associated colitis: two died, and one required hemicolectomy. Three of four patients carried the N1303K mutation. Severe and fatal C. difficile colitis can occur in cystic fibrosis patients, possibly with a genotype-specific predilection (i.e., N1303K/other). Because cystic fibrosis patients may have a wide spectrum of gastrointestinal symptoms, disease caused by C. difficile must be considered when these patients have acute abdominal pain, diarrhea, or severe leukocytosis.

A cystic fibrosis transmembrane conductance regulator splice variant with partial penetrance associated with variable cystic fibrosis presentations

Some patients express various features of cystic fibrosis (CF) even though essential characteristics of the disease might be absent. Such patients may suffer from respiratory disease without pancreatic insufficiency and normal sweat chloride levels. Others may present as male infertility because of congenital bilateral aplasia of the vas deferens (CBAVD) with no other signs of CF. The 5T allele, a DNA variant in a noncoding region of the cystic fibrosis transmembrane conductance regulator (CFTR) gene that reduces the level of the normal CFTR transcripts, was found in increased frequency among male patients with CBAVD. The purpose of this study was to investigate the possibility that the 5T allele is associated with dysfunction of organs other than the male reproductive system, leading to CF or atypical CF. Analysis of the 5T allele was performed on 148 subjects (29 with CF, 61 with atypical CF, and 58 with CBAVD) carrying 232 chromosomes with unidentified CFTR mutations, and on 142 non-CF chromosomes from healthy subjects of Ashkenazi origin. The frequency of the 5T allele among chromosomes from patients of Jewish Ashkenazi origin with CF and atypical CF (six of 33; 18%) was significantly higher than the frequency in the normal Ashkenazi population (eight of 142; 6%; p = 0.03). Analysis of the clinical presentation of the five patients with CF and the 12 patients with atypical CF carrying the 5T allele indicated that most patients suffered from respiratory disease presenting as asthma like symptoms, nasal polyposis, chronic sinusitis, chronic bronchitis, or bronchiectasis. Six patients had pancreatic insufficiency, two with meconium ileus. Sweat Cl- levels ranged from normal to elevated. Of the six male patients with respiratory disease who were old enough to be evaluated for fertility status, five were fertile and one had pancreatic insufficiency. Among male patients with CBAVD, 41% suffered from respiratory symptoms. Thus, the 5T allele is a variant with partial penetrance causing disease with an extreme variability of clinical presentation: from normal healthy fertile subjects or male patients with CBAVD to those with atypical or typical clinical phenotype of CF.

Highly variable incidence of cystic fibrosis and different mutation distribution among different Jewish ethnic groups in Israel

The incidence of cystic fibrosis (CF) and the frequency of disease-causing mutations varies among different ethnic and geographic populations. The Jewish population around the world is comprised of two major ethnic groups; Ashkenazi and non-Ashkenazi. The latter is further classified according to country of origin. In this study, we analyzed the incidence of CF and the distribution of CF mutations in the general Jewish population in Israel and in most of the Jewish ethnic subgroups. The disease frequency varies considerably among the latter. Among Ashkenazi Jews, the frequency of CF is 1:3300, which is similar to the frequency in most Caucasian populations. Among non-Ashkenazi Jews, the disease occurs at a similar frequency among Jews from Libya (1:2700), Georgia (1:2700), Greece and Bulgaria (1:2400), but is rare in Jews from Yemen (1:8800), Morocco (1:15000), Iraq (1:32000), and Iran (1:39000). So far, only 12 mutations have been identified in Israeli Jews, and this enables the identification of 91% of the CF chromosomes in the entire Jewish CF population. However, in each Jewish ethnic group, the disease is caused by a different repertoire of mutations. The frequency of identified mutations is high in Ashkenazi Jews (95%), and in Jews originating from Tunisia (100%), Libya (91%), Turkey (90%), and Georgia (88%). However, a lower frequency of mutations can be identified in Moroccan (85%), Egyptian (50%), and Yemenite (0%) Jews. For genetic counseling of a Jewish individual, it is necessary to calculate the residual risk according to ethnic origin. Carrier screening of healthy Jewish individuals is currently feasible for Ashkenazi Tunisian, Libyan, Turkish, and Georgian Jews. These results provide the required information for genetic counseling of Jewish CF families and screening programs of Jewish populations worldwide.

[Flexible bronchoscopy in the diagnosis of foreign body aspiration]

Foreign body aspiration (FBA) should be suspected in every child with acute onset of cough or wheezing. Although a choking episode occurs in 80-90% of cases of FBA, it is not necessarily diagnostic. Furthermore, in many cases neither physical examination nor chest x-ray, including fluoroscopy, are diagnostic; their results may be completely normal in up to 17-25% of cases of FBA. Bronchoscopy is therefore mandatory when there is a convincing history of FBA, regardless of physical or radiologic findings. This can be done with either the flexible or rigid bronchoscope, or with both.

Similar levels of mRNA from the W1282X and the delta F508 cystic fibrosis alleles, in nasal epithelial cells

The effect of nonsense mutations on mRNA levels is variable. The levels of some mRNAs are not affected and truncated proteins are produced, while the levels of others are severely decreased and null phenotypes are observed. The effect on mRNA levels is important for the understanding of phenotype-genotype association. Cystic fibrosis (CF) is a lethal autosomal recessive disease with variable clinical presentation. Recently, two CF patients with mild pulmonary disease carrying nonsense mutations (R553X, W1316X) were found to have severe deficiency of mRNA. In the Jewish Ashkenazi CF patient population, 60% of the chromosomes carry a nonsense mutation, W1282X. Patients homozygous for this mutation have severe disease presentation with variable pulmonary disease. The presence of CF transcripts in a group of patients homozygous and heterozygous for this mutation was studied by reverse transcriptase PCR of various regions of the gene. Subsequent hybridization to specific CF PCR probes and densitometry analysis indicated that the CF mRNA levels in patients homozygous for the W1282X mutation are not significantly decreased by the mutation. mRNA levels were compared for patients heterozygous for the W1282X mutation. The relative levels of mRNA with the W1282X, and the delta F508 or the normal alleles, were similar in each patient. These results indicate that the severe clinical phenotype of patients carrying the W1282X mutation is not due to a severe deficiency of mRNA. In addition, the severity, progression, and variability of the pulmonary disease are affected by other, as yet unknown factors.

Ciliary ultrastructure in primary ciliary dyskinesia and other chronic respiratory conditions: the relevance of microtubular abnormalities

Twenty-eight subjects with chronic respiratory disease were investigated for clinical data, ciliary beat frequency of nasal mucosa (10 cases), and ciliary ultrastructure. The cases were divided into two groups: those considered compatible with primary ciliary dyskinesia (genetic), and those not fitting into this category (others). A case was defined as genetic if one or more of the following were present: dextrocardia, ciliary beat frequency less than 10 Hz, or an average dynein arm count (outer, inner, or both) of less than two per ciliary cross-section. In each of the genetic cases at least two of these parameters were present. The percentage of malformed microtubules was calculated from the total number of evaluated cross-sections for each case. Ciliary microtubular abnormalities of any kind were no more frequent in cases of primary ciliary dyskinesia than in other cases. The same was true for transposition and radial spoke defects.

The contribution of perfusion scintigraphy in the evaluation of children suffering from recurrent localized pneumonia

The value of perfusion scintigraphy as a screening test for children who have suffered from several episodes of recurrent localized pneumonia was evaluated in 32 patients aged 1-15 years. Perfusion studies were carried out using macroaggregated albumin (MAA) labeled with technetium 99m. In 9 patients (28%), large lobar or multisegmental perfusion defects were demonstrated. Their final diagnoses proved to be bronchiectasis (5 patients), bronchomalacia (2 cases), agenesis of a lobe (1 subject), and lobar sequestration (1 patient). In 23 children (72%), the perfusion scintigraphic patterns were normal or diffusely nonhomogeneous. All of these patients improved clinically on a 1- to 2.9-year follow-up. We conclude that a normal perfusion scintigraphy is a useful screening test for excluding structural lung abnormalities in pediatric patients with recurrent localized pneumonia. Children showing a pattern of lobar or multisegmental perfusion defects should be further investigated to rule out structural abnormalities as an underlying cause of disease.

Functional immunoregulatory T-cell abnormalities in cystic fibrosis patients

The role of B cells and regulatory T cells in the reduced in vitro IgG synthesis of cystic fibrosis (CF) patients was studied. Intact proportion, proliferation, and differentiation of B cells and reduced suppressor and helper T-cell function were found. To explore the T-cell defects further, CF sera or supernatant derived from Pseudomonas aeruginosa cultures (PA supernatant) was added to the relevant T helper- and suppressor-cell assays. Both CF sera derived from PA-positive patients and PA supernatant interfered with the appearance of interleukin 2 (IL-2) receptors and with the functional enhancement caused by exogenously added IL-2. PA-negative CF patients, however, also had functional T-cell defects and inhibitory sera, but these sera did not affect IL-2 pathways. Thus different serum factors and intrinsic T-cell defects in CF patients are suggested.