Ataluren-driven restoration of Shwachman-Bodian-Diamond syndrome protein function in Shwachman-Diamond syndrome bone marrow cells.

Shwachman-Diamond syndrome (SDS) is a rare inherited recessive disease mainly caused by mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene, which encodes for the homonymous protein SBDS, whose function still remains to be fully established. SDS affects several organs causing bone marrow failure, exocrine pancreatic insufficiency, skeletal malformations, and cognitive disorders. About 15% of SDS patients develop myelodysplastic syndrome (MDS) and are at higher risk of developing acute myeloid leukemia (AML). Deficiency in SBDS expression has been associated with increased apoptosis and lack of myeloid differentiation in bone marrow hematopoietic progenitors. Importantly, most SDS patients carry nonsense mutations in SBDS. Since ataluren is a well-characterized small molecule inhibitor that can suppress nonsense mutations, here, we have assessed the efficacy of this drug in restoring SBDS expression in hematopoietic cells obtained from a cohort of SDS patients. Remarkably, we show that ataluren treatment readily restores SBDS protein expression in different cell types, particularly bone marrow stem cells. Furthermore, ataluren promotes myeloid differentiation in hematopoietic progenitors, reduces apoptotic rate in primary PBMCs, and brings mammalian target of rapamycin phosphorylation levels back to normal in both lymphoblasts and bone marrow mesenchymal stromal cells (BM-MSCs). Since a specific therapy against SDS is currently lacking, these results provide the rationale for ataluren repurposing clinical trials.

Electrophysiological evaluation of cystic fibrosis conductance transmembrane regulator (CFTR) expression in human monocytes.

BACKGROUND: Cystic fibrosis is caused by mutations of CFTR gene, a protein kinase A-activated anion channel, and is associated to a persistent and excessive chronic lung inflammation, suggesting functional alterations of immune cells. Leukocytes express detectable levels of CFTR but the molecule has not been fully characterized in these cells. METHODS: Freshly isolated monocytes from healthy individuals and CF patients were assessed by protein expression, single cell electrophysiological and membrane depolarization assays. RESULTS: We recorded chloride currents by patch clamp in healthy monocytes, after the administration of a CFTR stimulus. Currents were sensitive to a specific blocker of the CFTR channel, CFTRinh-172 and were absent in CF monocytes. Next, we evaluated the effects of ex vivo exposure of monocytes from cystic fibrosis patients carrying the F508del mutation to a chemical corrector, Vertex-325. We found an increase in CFTR expression by confocal microscopy and a recovery of CFTR function by both patch clamp and single cell fluorescence analysis. CONCLUSIONS: We confirm the expression of functional CFTR in human monocytes and demonstrate that blood monocytes can represent an adequate source of primary cells to assess new therapies and define diagnosis of CF. GENERAL SIGNIFICANCE: Tests to evaluate CFTR functional abnormalities in CF disease might greatly benefit from the availability of a convenient source of primary cells. This electrophysiological study promotes the use of monocytes as a minimally invasive tool to study and monitor CFTR function in individual patients.

Detection of CFTR protein in human leukocytes by flow cytometry.

Leukocytes have previously been shown to express detectable levels of the protein cystic fibrosis transmembrane conductance regulator (CFTR). This study aims to evaluate the application of flow cytometric (FC) analysis to detect CFTR expression, and changes thereof, in these cells. Aliquots (200 µL) of peripheral whole blood from 12 healthy control volunteers (CTRLs), 12 carriers of a CFTR mutation (CFC), and 40 patients with cystic fibrosis (CF) carrying various combinations of CFTR mutations were incubated with specific fluorescent probes recognizing CFTR protein expressed on the plasma membrane of leukocytes. FC was applied to analyze CFTR expression in monocytes, lymphocytes, and polymorphonuclear (PMN) cells. CFTR protein was detected in monocytes and lymphocytes, whereas inconclusive results were obtained from the analysis of PMN cells. Mean fluorescence intensity (MFI) ratio value and %CFTR-positive cells above a selected threshold were the two parameters selected to quantify CFTR expression in cells. Lowest variability and the highest reproducibility were obtained when analyzing monocytes. ANOVA results indicated that both parameters were able to discriminate monocytes of healthy controls and CF individuals according to CFTR mutation classes with high accuracy. Significantly increased MFI ratio values were recorded in CFTR-defective cells that were also able to improve CFTR function after ex vivo treatment with PTC124 (Ataluren), an investigative drug designed to permit the ribosome to read through nonsense CFTR mutations. The method described is minimally invasive and may be used in the monitoring of responses to drugs whose efficacy can depend on increased CFTR protein expression levels. © 2014 International Society for Advancement of Cytometry.

Challenging the diagnosis of cystic fibrosis in a patient carrying the 186-8T/C allelic variant in the CF transmembrane conductance regulator gene.

BACKGROUND: This report describe for the first time a clinical case with a CFTR allelic variant 186-8T/C (c.54-8 T/C) in intron 1 of CFTR and underline the importance of applying a combination of genetic and functional tests to establish or exclude a diagnosis of Cystic Fibrosis. In this case the diagnostic algorithm proposed for CF has been successfully applied at our Center and previous CF diagnosis assigned in a different Center was not confirmed. CASE PRESENTATION: A 38 year-old Italian woman had been treated as affected by CF since 2010, following diagnosis based on sweat tests (reported values of 73 and 57 mEq/L) and a clinical history consistent with CF. No mutations were identified by first level of genetic analysis. Afterwards the patient referred to our center for assessing the relevance of these findings. The genetic variant 186-8T/C (c.54-8 T/C) in intron 1 of the CFTR gene was detected by sequencing. Low-level interstitial-alveolar infiltration was recorded by high-resolution computerized tomography. Lung function was normal and sputum and Broncho Alveolar Lavage cultures resulted bacteriologically negative. Sweat chloride levels was re-assessed and resulted with values of 57 and 35 mEq/L, with a borderline range between 40 and 60 mEq/L. Nasal Potential Difference measurements resulted in three reliable measurements consistent with a non-CF phenotype. Differential diagnosis with ciliary dyskinesia was excluded, as was exon 2 skipping of CFTR gene that might have caused a CFTR functional defect. Furthermore, single cell fluorescence analysis in response to cAMP agonists performed in patient's monocytes overlapped those obtained in healthy donors. CONCLUSION: We concluded that this patient was not affected by CF. This case highlights the need for referrals to highly specialized centers and the importance of combined functional and genetic tests in making a correct diagnosis. Moreover, we confirmed a correlation between NPD tracings and cell depolarization in monocytes providing a rationale for proposing the use of leukocytes as a potential support for CF diagnosis.

Further characterization of Shwachman-Diamond syndrome: psychological functioning and quality of life in adult and young patients.

To assess psychosocial functioning and quality of life in a representative group of adult and young patients with Shwachman-Diamond syndrome (SDS), all patients 3 years old and over included in the Italian SDS Registry were investigated using an ad-hoc questionnaire for information about demography, education, socialization, rehabilitation therapy, and standardized questionnaires [SF-36, Child Behavior Check-List (CBCL)] for quality of life and behavior. Results were compared with those of a Cystic Fibrosis (CF) patient group, matched for age and sex. Eighty-one percent of patients answered. All but one adult patient lived with their parents, 24% had independent income, and 57% had a driver's license. Different levels (from mild to severe) of cognitive impairment were reported by 76% of the adults and by 65% of the young patients. These data are significantly lower than those of the CF group. Both groups present low scores in the emotional and mental health evaluations at SF-36, but SDS patients reported significantly more limitations in physical functioning (PF) and more body pain (BP) experiences. As reported by parents at CBCL, young SDS patients show more "social problems" (in the clinical area 31% SDS vs. 6% CF), "attention deficits disorder" (29% SDS vs. 0%CF), and "somatic complaints" (24% SDS vs. 12% CF). Psychosocial functioning is impaired in the majority of SDS patients, significantly more than in patients affected by CF.

An interactive computer program can effectively educate potential users of cystic fibrosis carrier tests.

The demand for cystic fibrosis (CF) carrier testing is steadily growing, not only from individuals with raised a priori carrier risk, but also from the general population. This trend will likely exceed the availability of genetic counselors, making it impossible to provide standard face-to-face genetic counseling to all those asking for the test. In order to reduce the time needed to educate individuals on the basics of the disease, its genetic transmission, and carrier testing peculiarities, we developed an educational method based on an interactive computer program (IC). To assess the effectiveness of this program and to compare it to a classical genetic counseling session, we conducted a comparative trial. In a population setting of people undergoing assisted reproduction, 44 individuals were randomly assigned to either receiving standard one-on-one genetic counseling or education by the IC program. We measured pre- and post-intervention knowledge about CF genetic transmission and carrier testing. Starting from an equivalent baseline of correct answers to a specially designed multiple-choice questionnaire (47% in the counselor group and 45% in the computer group) both groups showed a highly significant and similar increase (reaching 84% in the counselor group and 85% in the computer group). The computer program under evaluation can successfully educate individuals considering genetic testing for CF.

Occurrence, outcomes and predictors of portal hypertension in cystic fibrosis: A longitudinal prospective birth cohort study.

BACKGROUND: The reported prevalence of portal hypertension (PH) in Cystic Fibrosis is variable, incidence rates rarely provided and the utility of liver function tests (LFT's) early in life to predict PH is questionable. The aims were to (1) determine PH prevalence (P) and incidence rate (IR) and combined mortality transplant (MTX) data in PH vs non-PH patients and (2) to assess association of LFTs in early life with liver disease and PH. METHOD: (1) A double centre longitudinal cohort study of 577 CF patients diagnosed by newborn screening (NBS) with annual examinations for PH up to 18.5 years of age (max) was performed over 28 years for P, IR, and MTX data; (2) Cox proportional hazard models were used to assess the association of elevated LFTs on 2 or more occasions over 0-6.5 years and PH. RESULTS: 51/577(8.8%) developed PH with an average IR of near 3/1000 patient years per 5 year interval representing young, mid and late childhood respectively in patients 3-18 years of age. Combined mortality/liver transplant occurred in 12/51 (23.5%) PH and 25/526 (4.8%) non-PH (p < 0.001). Elevated enzymes particularly GGT (HR:5.71, 95% CI 3.11-10.47); ALT/GGT (HR: 5.56, 95% CI 2.82-10.98); and ALP/GGT (HR: 5.74, 95% CI 2.78-11.86) were associated with the onset of PH. CONCLUSION: This birth cohort with annual examination for PH provides an accurate assessment of the prevalence, and IR of PH and MTX of PH vs non-PH. Early elevated LFTs are associated with onset of MBC/PH.

Association between carrier screening and incidence of cystic fibrosis.

CONTEXT: A downward trend in cystic fibrosis (CF) birth incidence has been reported in some areas. OBJECTIVE: To evaluate the association between carrier screening and CF birth incidence. DESIGN, SETTING, AND PARTICIPANTS: In northeastern Italy, CF birth incidence is monitored by means of a long-standing neonatal screening program. In the same area, 2 sections using different carrier detection approaches were identified--the western region, in which CF carrier tests are offered only to relatives of patients or to couples planning in vitro fertilization; and the eastern region, in which carrier testing is offered to relatives and carrier screening to infertile couples and to couples of reproductive age. A total of 779,631 newborns underwent CF neonatal screening between January 1993 and December 2007, of whom 195 had CF detected. MAIN OUTCOME MEASURE: Cystic fibrosis birth incidence in the 2 regions. RESULTS: A time-related decrease in birth incidence was found, with a mean annual percentage decrease of 0.16 per 10,000 neonates (P < .001). In the western region, 2559 carrier tests were performed, 314 carriers were identified, and 9 carrier couples were detected. In the eastern region, 87,025 carrier tests were performed, 3650 carriers were identified, and 82 carrier couples were detected. The birth rate decrease was greater in the eastern region (decrease rate, 0.24; 95% confidence interval [CI], 0.12-0.36) than in the western region (decrease rate, 0.04; 95% CI, -0.16 to 0.08; P = .01). The increase in the number of screened carriers over time was significantly correlated with the decrease in CF birth incidence (correlation coefficient = -0.53; 95% CI, -0.20 to -0.74; P = .003). CONCLUSION: In northeastern Italy, carrier screening was associated with a decrease in the incidence of CF.

Cystic fibrosis transmembrane conductance regulator functional evaluations in a G542X+/- IVS8Tn:T7/9 patient with acute recurrent pancreatitis.

BACKGROUND: Acute recurrent pancreatitis (ARP) is characterized by episodes of acute pancreatitis in an otherwise normal gland. When no cause of ARP is identifiable, the diagnosis of "idiopathic" ARP is given. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene increase the risk of ARP by 3- to 4-times compared to the general population, while cystic fibrosis (CF) patients present with a 40- to 80-times higher risk of developing pancreatitis. CASE SUMMARY: In non-classical CF or CFTR-related disorders, CFTR functional tests can help to ensure a proper diagnosis. We applied an individualized combination of standardized and new CFTR functional bioassays for a patient referred to the Verona CF Center for evaluation after several episodes of acute pancreatitis. The CFTR genotype was G542X+/- with IVS8Tn:T7/9 polymorphism. The sweat (Cl-) values were borderline. Intestinal current measurements were performed according to the European Cystic Fibrosis Society Standardized Operating Procedure. Recent nasal surgery for deviated septum did not allow for nasal potential difference measurements. Lung function and sputum cultures were normal; azoospermia was excluded. Pancreas divisum was excluded by imaging but hypoplasia of the left hepatic lobe was detected. Innovative tests applied in this case include sweat rate measurement by image analysis, CFTR function in monocytes evaluated using a membrane potential-sensitive fluorescent probe, and the intestinal organoids forskolin-induced swelling assay. CONCLUSION: Combination of innovative CFTR functional assays might support a controversial diagnosis when CFTR-related disorders and/or non-classical CF are suspected.

Chest computed tomography scores in patients with cystic fibrosis colonized with methicillin-resistant Staphylococcus aureus.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen in cystic fibrosis (CF), with increasing incidence in recent years. We examined the association between bacterial colonization in the sputum (MRSA with or without pseudomonas (PA)) and computed tomography (CT) scores in CF patients. METHODS: MRSA patients were divided according to PA status based on at least three consecutive sputum cultures; controls were patients without MRSA (with or without PA), matched for gender and age at CT. Clinical data and CT scores were compared between groups. RESULTS: Of 33 patients with MRSA, 14 had no PA (MRSA + PA-) and 19 had also PA (MRSA + PA+). MRSA + PA- and MRSA + PA+ patients had CT scores similar to their controls PA+ (38.25 ± 20.18 vs. 32.22 ± 18.74, P = .4, and 41.88 ± 18.18 vs. 45.33 ± 11.5, P = .4, respectively). Although MRSA + PA- had worse CT scores than their matched PA- controls, their mean FEV1 values were similar. CONCLUSIONS: Colonization with MRSA in CF is associated with structural CT changes at least similar to those in PA. A cause and effect relationship cannot be established. The current findings call for a larger study assessing longitudinally the impact of MRSA acquisition and eradication protocols.

Ratiometric sweat secretion optical test in cystic fibrosis, carriers and healthy subjects.

We have simplified the published procedure (5) for measuring sweat rates in individual human sweat glands. Sweat secretion rates were obtained from sweat drops secreted on the forearm by multiple individual glands. We computed a ratio between CFTR-dependent (by intradermal microinjection of a ß adrenergic cocktail) and CFTR-independent (by methacoline as cholinergic stimulus) sweat secretion rates. We obtained a reproducible, approximately linear readout of CFTR function with measurements performed by two different independent teams. We considered three groups (CF subjects, CF carriers and non-CF controls, n=22 in each group); their mean ratios was respectively 0.000, 0.104 and 0.205 The average ratio of CF subjects was consistent with diagnosis in 3 additional cases clinically resembling CF. All groups were clearly discriminated, with sensibility and specificity ranging from 82% to 100%. A software was developed for detecting sweat droplets. This bioassay is suitabile for multicentre studies focusing on CFTR targeted therapies, controversial diagnosis and functional relevance of rare CFTR mutations.

The Italian registry of pulmonary non-tuberculous mycobacteria - IRENE: the study protocol.

BACKGROUND: A substantial increase in pulmonary and extra-pulmonary diseases due to non-tuberculous mycobacteria (NTM) has been documented worldwide, especially among subjects suffering from chronic respiratory diseases and immunocompromised patients. Many questions remain regarding the epidemiology of pulmonary disease due to NTM (NTM-PD) mainly because reporting of NTM-PD to health authorities is not mandated in several countries, including Italy. This manuscript describes the protocol of the first Italian registry of adult patients with respiratory infections caused by NTM (IRENE). METHODS: IRENE is an observational, multicenter, prospective, cohort study enrolling consecutive adult patients with either a NTM respiratory isolate or those with NTM-PD. A total of 41 centers, including mainly pulmonary and infectious disease departments, joined the registry so far. Adult patients with all of the following are included in the registry: 1) at least one positive culture for any NTM species from any respiratory sample; 2) at least one positive culture for NTM isolated in the year prior the enrolment and/or prescribed NTM treatment in the year prior the enrolment; 3) given consent to inclusion in the study. No exclusion criteria are applied to the study. Patients are managed according to standard operating procedures implemented in each IRENE clinical center. An online case report form has been developed to collect patients' demographics, comorbidities, microbiological, laboratory, functional, radiological, clinical, treatment and outcome data at baseline and on an annual basis. An IRENE biobank has also been developed within the network and linked to the clinical data of the registry. CONCLUSIONS: IRENE has been developed to inform the clinical and scientific community on the current management of adult patients with NTM respiratory infections in Italy and acts as a national network to increase the disease's awareness. TRIAL REGISTRATION: Clinicaltrial.gov: NCT03339063.

Nasal potential difference outcomes support diagnostic decisions in cystic fibrosis.

BACKGROUND: When cystic fibrosis (CF) is suspected Nasal Potential Difference (NPD) measurements are proposed to support controversial diagnosis: we investigated appropriate outcomes at the CF Centre of Verona. SUBJECTS/METHODS: NPD were measured in 196 subjects: 50 non-CF, 65 classical CF (the reference group) and 81 with uncertain CF (case group). Discriminating power was determined by comparison between several outcomes from the CF reference group versus non-CF: basal, amiloride, 0Cl, isoproterenol, ATP, Delta-amiloride, Delta-0Cl, Delta-isoproterenol, Delta-ATP, Delta-isoproterenol+Delta-0Cl, Wilschanski Index (WI) and Sermet score (SS). The most appropriate cut-off values for variables with the best discriminating power were then applied to the case group. Descriptive statistics, logistic regression models and ROC curve analysis were applied. RESULTS: WI and SS were the most powerful in discriminating CF from non-CF subjects. In the reference group sensitivity of the 0.82 WI cut-off was 98%, specificity 96%; both sensitivity and specificity of the -0.44 SS cut-off value were 100%. For the case group, WI and SS were, respectively, consistent with CF diagnosis in 94% and 92% of the cases. CONCLUSIONS: Formulae have the highest discriminating power and can support the diagnosis in uncertain cases; they should be utilized for standardized interpretation of NPD for diagnosis and possibly for clinical research.

New insights into the Shwachman-Diamond Syndrome-related haematological disorder: hyper-activation of mTOR and STAT3 in leukocytes.

Shwachman-Diamond syndrome (SDS) is an inherited disease caused by mutations of a gene encoding for SBDS protein. So far little is known about SBDS exact function. SDS patients present several hematological disorders, including neutropenia and myelodysplastic syndrome (MDS), with increased risk of leukemic evolution. So far, the molecular mechanisms that underlie neutropenia, MDS and AML in SDS patients have been poorly investigated. STAT3 is a key regulator of several cellular processes including survival, differentiation and malignant transformation. Moreover, STAT3 has been reported to regulate neutrophil granulogenesis and to induce several kinds of leukemia and lymphoma. STAT3 activation is known to be regulated by mTOR, which in turn plays an important role in cellular growth and tumorigenesis. Here we show for the first time, to the best of our knowledge, that both EBV-immortalized B cells and primary leukocytes obtained from SDS patients present a constitutive hyper-activation of mTOR and STAT3 pathways. Interestingly, loss of SBDS expression is associated with this process. Importantly, rapamycin, a well-known mTOR inhibitor, is able to reduce STAT3 phosphorylation to basal levels in our experimental model. A novel therapeutic hypothesis targeting mTOR/STAT3 should represent a significant step forward into the SDS clinical practice.

Cationic trypsinogen and pancreatic secretory trypsin inhibitor gene mutations in neonatal hypertrypsinaemia.

Neonatal hypertrypsinaemia with normal sweat chloride detected during CF screening may be related to trypsin activation. We have looked for mutations of the cationic trypsinogen (PRSS1) and pancreatic secretory trypsin inhibitor (PSTI) genes in 50 hypertrypsinaemic neonates with known CFTR genotypes and negative sweat test. No mutations were found in either gene. Two silent polymorphisms were detected in the PRSS1 gene. A polymorphism in the promoter region and an intronic polymorphism of the PSTI gene were found. No difference was observed in the frequency of PRSS1 or PSTI polymorphisms in neonates carrying or not carrying CF mutations. These results do not provide an indication for an increased frequency of mutations in the PRSS1 and PSTI genes in this group of neonates with transient hypertrypsinaemia.

Mutations in the SPINK1 gene in idiopathic pancreatitis Italian patients.

Idiopathic chronic and acute recurrent pancreatitis (IP) have been associated with mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Mutations in the serine protease inhibitor Kazal 1 (SPINK1) have been described in some idiopathic chronic patients and it has been suggested that mutations in this gene could be responsible for a loss of trypsin inhibitor function. In this study, the 5'UTR region, and the four exons and exon-intron boundaries of the SPINK1 gene in 32 IP patients have been analyzed. Three IP patients (9.3%) and one control/100 carried the N34S mutation of the SPINK1 gene (Fisher's exact test, P=0.044). No other mutation that could be associated with an altered function of the SPINK1 protein was observed. The N34S mutation was present in two patients who carried the CFTR-IVS8 5T variant and in one who carried the L997F variant in the CFTR gene. The association of SPINK1 with CFTR gene mutations in IP patients is statistically significant (3/32 IP cases and 0/100 control individuals carrying mutations in both genes; Fisher's exact test P=0.01).

Hyaluronic acid improves the tolerability of hypertonic saline in the chronic treatment of cystic fibrosis patients: a multicenter, randomized, controlled clinical trial.

UNLABELLED: TRIAL DESIGN AND METHODS: Between December 2009 and July 2011, four cystic fibrosis (CF) centers in Italy participated in a randomized, double-blind, controlled clinical trial to test whether 7% hypertonic saline (HS) administered together with 0.1% hyaluronic acid (HA) was better tolerated by patients who previously did not tolerate HS well on its own. Participants were CF patients at least 8 years old, in clinically stable conditions, with forced expiratory volume in 1 sec (FEV1) at least 50% predicted. Forty patients were recruited and randomized to receive either HS or HS plus HA (5 mL to be inhaled over 15 min, twice daily for 28 days). Primary endpoints were cough, throat irritation, salty taste, and overall acceptability, as assessed by each patient on a semiquantitative scale on a diary card. Secondary endpoint was FEV1 change at the end of treatment. Patients were randomized into randomly permuted blocks. The first and last doses were administered in hospital. In between, patients were treated at home. Patients, all caregivers, and the statistician who conducted the analysis (different from the one who generated the random list) were blinded to group assignment. RESULTS: Severity of cough, throat irritation, and saltiness were more severe in patients treated with HS alone, both after the first inhalation and over the entire treatment period. Overall pleasantness was rated higher by patients treated with the combination product. All differences were highly significant. There were no changes in FEV1 between the first and last administrations. Five patients did not complete the study. Four patients (two from each group) withdrew because of cough or throat irritation. One more patient from the HS group withdrew because of a respiratory exacerbation at week 3. CONCLUSIONS: HS is currently a cornerstone in the treatment of CF patients. The addition of HA to HS reduces the prevalence and severity of cough, throat irritation, and saltiness and may improve compliance in patients who previously did not tolerate HS well on its own. Longer-term studies could further assess the benefit of chronic treatment.

Impact of MIF gene promoter polymorphism on F508del cystic fibrosis patients.

Macrophage migration Inhibitory Factor (MIF) is a pro-inflammatory cytokine sustaining the acute response to gram-negative bacteria and a regulatory role for MIF in Cystic Fibrosis has been suggested by the presence of a functional, polymorphic, four-nucleotide repeat in this gene's promoter at position -794, with the 5-repeat allele displaying lower promoter activity. We aimed at assessing the association of this polymorphism with disease severity in a group of Cystic Fibrosis patients homozygous for F508del CFTR gene mutation. Genotype frequencies were determined in 189 Cystic Fibrosis and 134 control subjects; key clinical features of patients were recorded and compared among homozygous 5-allele patients and the other MIF genotypes. Patients homozygous for the 5-repeat allele of MIF promoter displayed a slower rate of lung function decline (p = 0.027) at multivariate survival analysis. Multiple regression analysis on age-normalized respiratory volume showed no association of the homozygous 5-repeat genotype with lung function under stable conditions and no correlation with P.aeruginosa chronic colonization. Therefore, only the Homozygous 5-repeat genotype at MIF -794 is associated with milder disease in F508del Cystic Fibrosis patients.

Impaired CFTR function in mild cystic fibrosis associated with the S977F/T5TG12complex allele in trans with F508del mutation.

BACKGROUND: The S977F mutation (c.2930C>T) in the CFTR gene (CFTR/ABCC7) is extremely rare. We describe the case of an adult patient carrying the complex allele S977F/T5TG12 in trans with the F508del mutation. Mild respiratory manifestations arose in adulthood associated with azoospermia, acute pancreatitis, minor hemoptysis and Cl(-) levels ranging from 40 to 42 mEq/L. METHOD: Diagnosis was confirmed by repeated NPD measurements, genetic DHPLC analysis and a recently described functional assay measuring cAMP-dependent cell depolarization in peripheral blood monocytes. RESULTS: NPD measurements, DHPLC and monocyte functional assay (CF index=-18). Results were consistent with a CF phenotype. CONCLUSIONS: The combined application of DHPLC and NPD analysis in the algorithm for CF diagnosis appears useful for the management of similar cases. In addition, the novel monocyte functional assay might contribute to improve our diagnostic capability, counseling and better treatment of these challenging clinical cases.

MudPIT analysis of released proteins in Pseudomonas aeruginosa laboratory and clinical strains in relation to pro-inflammatory effects.

Pseudomonas aeruginosa (Pa) is the most common virulent pathogen contributing to the pathogenesis of cystic fibrosis (CF). During bacterial lung colonization, the products of its metabolism are released in the extracellular space contributing to the pathogenic events associated with its presence. To gain insights on the mechanisms involved in the Pa pathogenesis we focused our attention on proteins released by Pa using a MudPIT approach combined with cell biology assays. Conditioned medium (CM) collected under aerobic and microaerobic conditions from Pa clinical strains (in early and late colonization), unlike the laboratory strain, induced expression of IL-8 mRNA in CF airway epithelial cells. We have identified proteins released by clinically relevant Pa strains, focusing on the pro-inflammatory effects as metalloproteases (MMPs). In fact, their expression pattern was associated with the highest pro-inflammatory activity measured in the early clinically isolated strain. The relation was further supported by the result of the analysis of a larger and independent set of Pa isolates derived from sporadically and chronically infected CF patients: 76% of sporadic samples expressed protease activity (n = 44), while only 27% scored positive in the chronically infected individuals (n = 38, p < 0.0001, Fisher's exact test). Finally, looking for a possible mechanism of action of bacterial MMPs, we found that CM from early clinical isolates can cleave CXCR1 on the surface of human neutrophils, suggesting a potential role for the bacterially released MMPs in the protection of the pathogen from the host's response.