Guidelines for the clinical management and follow-up of infants with inconclusive cystic fibrosis diagnosis through newborn screening.

Neonatal screening for cystic fibrosis (CF) can detect infants with elevated immunoreactive trypsinogen (IRT) levels and inconclusive sweat tests and/or CFTR DNA results. These cases of uncertain diagnosis are defined by (1) either the presence of at most one CF-associated cystic fibrosis transmembrane conductance regulator (CFTR) mutation with sweat chloride values between 30 and 59mmol/L or (2) two CFTR mutations with at least one of unknown pathogenic potential and a sweat chloride concentration below 60mmol/L. This encompasses various clinical situations whose progression cannot be predicted. In these cases, a sweat chloride test has to be repeated at 12 months, and if possible at 6 and 24 months of life along with extended CFTR sequencing to detect rare mutations. When the diagnosis is not definite, CFTR functional explorations may provide a better understanding of CFTR dysfunction. The initial evaluation of these infants must be conducted in dedicated CF reference centers and should include bacteriological sputum analysis, chest radiology, and fecal elastase assay. The primary care physicians in charge of these patients should be familiar with the current management of CF and should work in collaboration with CF centers. A follow-up should be performed in a CF reference center at 3, 6, and 12 months of life and every year thereafter. Any symptom indicative of CF requires immediate reevaluation of the diagnosis. These guidelines were established by the "neonatal screening and difficult diagnoses" working group of the French CF society. Their objective is to standardize the management of infants with unclear diagnosis.

[Management of infants whose diagnosis is inconclusive at neonatal screening for cystic fibrosis]. / Recommandations pour la prise en charge et le suivi des nourrissons pour lesquels un diagnostic de mucoviscidose n'a pu être conclu après dépistage néonatal.

Neonatal screening for cystic fibrosis (CF) may detect infants with elevated immunoreactive trypsinogen (IRT) levels but with inconclusive sweat tests and/or DNA results. This includes cases associating (1) either the presence of at most one CF-causing mutation and sweat chloride values between 30 and 59mmol/L or (2) two CFTR mutations with at least one of unknown pathogenicity and a sweat chloride below 60mmol/L. This encompasses different clinical situations whose progression cannot be predicted. These cases require redoing the sweat test at 12 months and if possible at 6 and 24 months of life. This must be associated with extended genotyping. CFTR functional explorations can also help by investigating CFTR dysfunction. These infants must be initially evaluated in dedicated CF centers including bacteriological sputum analysis, chest radiology and fecal elastase dosage. A home practitioner must be informed of the specificity of follow-up. These infants will be reviewed in the CF center at 3, 6 and 12 months and every year. Any CF-related symptom requires reevaluation of the diagnosis. These guidelines were established by the "neonatal screening and difficult diagnoses" working group of the French CF Society. They aim to standardize management of infants with unclear diagnosis in French CF centers.

Vaccine coverage in CF children: A French multicenter study.

BACKGROUNDS: Recent reports have pointed the low vaccine coverage in patients with chronic diseases. Data are lacking in patients with cystic fibrosis (CF). Gaining more information on coverage both for mandatory vaccines and those more specifically recommended would help to optimize care of these patients. METHODS: Data were extracted from the "MucoFlu" study, which was a prospective study performed in 2009 in the 5 cystic fibrosis centers of the Paris metropolitan area. Data on mandatory and recommended vaccines in CF were collected in the health booklet and compared to the coverage of the general population. RESULTS: A total of 134 CF children were included. Vaccination coverage for mandatory vaccines was insufficient (DTPCaHi, conjugate pneumococcal, BCG, MMR and hepatitis B) at 1year of age with no catching-up with age in contrast to the general population. Approximately 66% of the children had immunization for seasonal influenza and 91% for 2009 pandemic flu. Coverage for vaccines specifically recommended in CF was low for hepatitis A, non conjugate pneumococcal and varicella. CONCLUSION: This study shows a defect in vaccine coverage for both routine immunization and vaccines more specifically recommended in CF.

Factors associated with humoral immune response to pandemic A/H1N1(v) 2009 influenza vaccine in cystic fibrosis.

Influenza vaccination is recommended in cystic fibrosis patients. The objective of this study was to assess the immunogenicity of vaccination against 2009 pandemic A/H1N1 influenza and to study the factors associated with the immune response in patients with cystic fibrosis. 122 patients with cystic fibrosis were enrolled in a prospective study and received 1 dose of 2009/H1N1v adjuvanted vaccine, or for children <2 years and lung-transplanted patients, two doses of non-adjuvanted 2009/H1N1v vaccine administered 21 days apart. Hemagglutination inhibition antibodies were assessed before and 21 days after vaccination and at least 6 months after vaccination. After vaccination, 85% of the patients had an influenza antibody titer ≥1:40 and 69% seroconverted. 13% of the transplanted patients seroconverted compared with 72% of the non-transplanted patients. In this latter group, non-adjuvanted vaccine and low body mass index were independently associated with lower response to vaccination. 86% of the non-transplanted patients with normal BMI and receiving adjuvanted vaccine seroconverted. Persistence of seroprotection 10 months after vaccination was found in 50% of the patients. In patients with cystic fibrosis, malnutrition and receipt of non-adjuvanted vaccine were associated with lower immune response to pandemic influenza vaccination. Our data also suggest a potential defect in the immune response to influenza vaccination of patients with cystic fibrosis and raise the question of whether a different immunization strategy is needed.

[Genetics and immunity of tuberculosis]. / Génétique et immunité de la tuberculose.

Tuberculosis, caused by Mycobacterium tuberculosis, is the most common mycobacterial disease in the world and remains a leading public health problem. Numerous other mycobacterial species are present in the environment and are most often termed atypical or nontuberculous mycobacteria. Like the attenuated vaccine Bacille Calmette-Guérin (BCG) they are generally poorly virulent, even so they can be at the origin of severe infections if the host immune response is impaired. It has been clearly demonstrated that the intrinsic virulence of a mycobacterial species is not the only factor determining disease severity, which is illustrated by the observation that the majority of individuals infected with M. tuberculosis do not develop clinical disease. Numerous arguments suggest that disease severity depends largely on susceptibility/resistance determined by the host genetic make up. In the following review we will discuss the studies on the genes implicated in complex predisposition to tuberculosis and Mendelian predisposition to disease caused by less virulent mycobacteria, proposing a continuous spectrum between those two types of predisposition.

Chronic cases of tuberculosis in Casablanca, Morocco.

OBJECTIVE: To evaluate the prevalence and patterns of drug resistance of Mycobacterium tuberculosis isolates collected from patients with chronic tuberculosis in Casablanca, Morocco. METHODS: Between February 1996 and September 2001, 122 isolates were recovered from 112 different patients. The male to female ratio was 2.4. RESULTS: From February 1996 to May 1997, 77.5% of isolates were multidrug-resistant (MDR-TB), compared to 69.4% from February 1999 to May 2000 and 78.7% from June 2000 to September 2001. The prevalence of MDR-TB is similar from the initial to the last period of this study. Analysis of the 69 bp hypervariable region of the rpoB gene by DNA sequencing on 42 M. tuberculosis isolates (37 resistant, 5 sensitive) showed nine different types of mutations on codons rpoB 513, rpoB 516, rpoB 522, rpoB 523 and rpoB 526. A new point mutation was observed on codon rpoB 523 on one isolate. No mutation was detected on this rpoB region for four resistant isolates. CONCLUSION: The high rate of MDR-TB illustrates a serious problem. The public health authorities have introduced a new regimen protocol consisting of 3 months of kanamycin, ofloxacin, pyrazinamide and ethionamide, followed by 18 months of ofloxacin, pyrazinamide and ethionamide (3KOZEA/18OZEA) for this category of patients, and it is hoped that the additional use of ofloxacin during the intensive phase of treatment will reduce the rate of resistance.

Variants of the human NRAMP1 gene and susceptibility to tuberculosis in Morocco.

It has been well established that the host genetic background is an important modulator of tuberculosis susceptibility. The NRAMP1 (alias SLC11A1) gene has been associated with tuberculosis susceptibility in several ethnic groups. Here we studied the association and linkage of NRAMP1 with tuberculosis in 116 nuclear families, comprising 211 affected offspring, from Casablanca, Morocco. All enrolled tuberculosis cases were culture-positive. No evidence was found of linkage or association of NRAMP1 with tuberculosis. These findings suggest heterogeneity in the genetic control of tuberculosis susceptibility.

Impaired interferon gamma-mediated immunity and susceptibility to mycobacterial infection in childhood.

Mendelian susceptibility to poorly virulent mycobacteria such as bacillus Calmette-Guerin (BCG) and environmental nontuberculous mycobacteria is a clinically heterogeneous syndrome. The clinical features of affected children cover a continuous spectrum from disseminated lethal bacillus Calmette-Guerin infection to local recurrent nontuberculous mycobacterial infection. Different types of mutations in four genes (IFNGR1, IFNGR2, IL12B, IL12RB1) have revealed both allelic and nonallelic heterogeneity and result in eight different disorders whose common pathogenic pathway is impaired interferon gamma (IFNgamma) mediated immunity. The severity of the clinical phenotype depends on the genotype. Complete IL-12 p40 and IL-12 receptor beta1 deficiencies and partial IFNgamma receptor 1 (IFNgammaR1) and IFNgammaR2 deficiencies generally lead to curable infections at various ages, and antibiotics supplemented with IFNgamma if required are likely to be effective. Complete IFNgammaR1 and IFNgammaR2 deficiencies predispose to overwhelming infection in early childhood, which may respond to antibiotics but relapse when antibiotics are discontinued. Rapid discrimination between complete IFNgammaR1 and IFNgammaR2 deficiency and other defects, therefore, is an important diagnostic step for planning clinical management.

Mycoserological study of the treatment of paediatric cystic fibrosis patients with Saccharomyces boulardii (Saccharomyces cerevisiae Hansen CBS 5926).

Saccharomyces boulardii (SB) (Saccharomces cerevisiae Hansen CBS 5926) is a yeast widely used in humans for the prevention and treatment of infectious enterocolitis. SB is said also to antagonize Candida albicans when given orally to living organisms. This double-blind trial was performed to determine the effect and tolerance of SB as an oral therapeutic in patients suffering from cystic fibrosis receiving long-term treatment with cephalosporins or cotrimoxazole, by examining C. albicans counts in the intestine. Extensive mycoserological examinations for drug safety evaluation were also performed. To be selected for the study patients had to present C. albicans in their intestinal flora. None of the patients enrolled exhibited clinical symptoms of candidosis. A daily dose of 750 mg (250 mg t.i.d.) of lyophilized SB given for 21 days did not affect the number of C. albicans commensals in those patients. However, the mycoserological data confirmed the safety of SB treatment with respect to a hypothetically possible SB fungaemia and a possible falsification of Candida serology.

[Fat metabolism in growth-selected laboratory mice]. / Untersuchungen zum Fettstoffwechsel wachstumsselektierter Labormäuse.

The object of the present study was to characterize the selection-conditioned differentiation of the biological performance of laboratory mice having been selected for 13 generations at the age of 6 weeks to body mass (Du-6) as well as simultaneously to body mass and high physical capacity (Du-6 + LB) by parameters of fat metabolism. The improved physical capacity with unchanged body composition (Du-6 + LB) coincides with increasing activity of dehydrogenases supplying NADPH (glucose-6-phosphate-dehydrogenase, 6-phosphate-gluconate-dehydrogenase, NADP-malate-dehydrogenase, NADP-isocitrate-dehydrogenase) in the liver. The doubling of the fat content of the body (Du-6) was accompanied by a significant increase of the G-6-PDH- and fatty-acid synthetase activity in the fatty tissue. Furthermore, the growth-selected animals showed an intensified transformation of 14C-glucose substrate in the lipids of the epididymal fatty tissues occurring especially at the selection age (42nd day) as well as at the earlier date of ontogenesis (32nd day). The insulin stimulation capacity of the fat cells as to the glucose incorporation, however, remained unchanged.

Selection for different growth parameters in laboratory mice and its correlated effects on body composition and organ weights.

Body composition and organ weights were determined in male mice sampled from 4 different lines of a selection experiment: DU-6P (selected for high protein amount), DU-6 (selected for high body weight), DU-6 + LB (selected for an index combining body weight and endurance fitness) and DU-K (unselected control line). Selection was carried out under the conditions of ad libitum feeding and standardization of litter size at birth. In all 3 selection lines a significant direct selection response was shown. While fat in lines DU-6P and DU-6 + LB remained normal, it increased after selection for body weight (DU-6) significantly. Up to generation 13 the average increase of fat was 0.32% per generation. Investigations on 28 to 80 days old mice showed, that males of this line were fatter before, at and after the age of selection (42 days). After 9 generations the body weight of selected mice was significantly increased by 23 to 29%. The absolute organ weights of hearts, livers and kidneys were also significantly higher, while the relative weights of hearts and kidneys decreased. The relative liver weights were in the selected lines higher, but only the difference DU-6 vs. DU-K was significant.