Cardiopulmonary testing in adult patients with ß-thalassemia major in comparison to healthy subjects.

ß-Thalassemia patients often have a reduced capacity of exercise and abnormal respiratory function parameters, but the reasons are unclear. In order to identify the causes of the exercise limitation, we performed a cardiopulmonary exercise testing (CPET) in a group of 54 adult ß-thalassemia major (TM) patients without pulmonary arterial hypertension and in a group of healthy control subjects. All subjects underwent cardiac echocardiography and carried out pulmonary function tests. TM patients also filled an IPAQ questionnaire on usual physical activity (PA).Overall, TM patients have a diminished exercise performance in comparison to control subjects. In fact, peak oxygen uptake (V'O2 peak), expressing maximum exercise capacity, was decreased in 81.5% of the patients; similarly, anaerobic threshold (V'O2@AT) and O2 pulse also resulted lowered. In multivariable regression models adjusted for gender, age, BMI, and mean haemoglobin, V'O2 peak and O2 pulse were positively associated with cardiac iron overload (T2*). No ventilatory limitation to exercise was observed. The most important causes of exercise limitation in these patients were muscular deconditioning and reduced cardiac inotropism due to iron deposition. Only 15/54 (27.8%) TM patients used to perform vigorous physical activity. These results suggest that a program of regular physical activity may be useful to increase the tolerance to effort and therefore to improve the quality of life in these patients.

Selective delivery of pentamidine toward cancer cells by self-assembled nanoparticles.

Pentamidine (PTM) is an aromatic diamidine approved for the treatment of parasitic infections that has been recently proposed for possible repositioning as an anticancer drug. To this aim, efforts have been made to improve its therapeutic efficacy and reduce associated adverse effects through both covalent derivatization and association with nanocarriers. To efficiently encapsulate PTM into biocompatible nanoparticles and to enhance its selectivity toward cancer cells, a squalene (SQ) derivative (1,1',2-tris-norsqualenoic acid, SQ-COOH) was selected to prepare PTM-loaded nanocarriers. Indeed, SQ and its derivatives self-assemble into nanoparticles in aqueous media. Furthermore, SQ-bioconjugates strongly interact with low-density lipoproteins (LDL), thus favoring preferential accumulation in cells overexpressing the LDL receptor (LDLR). We report here the preparation of nanocarriers by ion-pairing between the negatively charged SQ-COOH and the positively charged PTM free base (PTM-B), which allowed the covalent grafting of SQ to PTM to be avoided. The nanoparticles were characterized (mean size < 200 nm and zeta potential < -20 mV for SQ-COOH/PTM-B 3:1 molar ratio) and molecular modelling studies of the SQ-COOH/PTM-B interaction confirmed the nanocarrier stability. Finally, the ability to indirectly target LDLR-overexpressing cancer cells was evaluated by in vitro cell viability assays and confirmed by LDLR silencing, serum privation and simvastatin treatment.

Improved isolation of carbapenem-resistant Enterobacterales on selective-differential media extending the incubation time: an approach to strengthen the antimicrobial surveillance from rectal swabs.

BACKGROUND: Surveillance of carbapenem-resistant Enterobacterales (CRE) carriers is the first measure of hospital infection control. Screening of CRE carriage can be assessed through culture and molecular techniques, each with specific properties of turnaround-times, sensitivity and specificity. METHODS: This was a prospective study in a 1200-bed university hospital in Genoa, Italy, where CRE screening is performed analysing cultures from rectal swabs. Our 18-months intervention was to extend the incubation time of the corresponding plates from 48 to 288 h, after reporting negative tests, to evaluate the possible impact on the cultures. FINDINGS: A total of 362 patients giving 19,278 swabs and corresponding plates were included. After baseline incubation, plate positivity was 3%, while after the overall lengthened times it was 3.7%. Extended incubation was associated with change in the relative frequency of the most represented species. In particular, we observed reduced presence of total and resistant Klebsiella pneumoniae strains (P<0.001) and increased presence of Enterobacter cloacae complex, total and sensitive (P<0.001). By extending incubation time, a reduced frequency of overall Enterobacterales strains with high resistance to ertapenem (MIC ≥4 mg/L) was also found (P=0.005), particularly that of K. pneumoniae (P<0.001), while the presence of E. cloacae complex increased among organisms with low resistance levels to ertapenem (P<0.001). CONCLUSIONS: Extending the incubation time of the cultures increased the number of CREs grown, and expanded the bacterial scenario of rectal colonization through the recovery of poorly resistant strains and otherwise undetected species.

Colonization by Candida auris in critically ill patients: role of cutaneous and rectal localization during an outbreak.

BACKGROUND: Candida auris infections have been reported worldwide since the pathogen was isolated in 2009. AIM: To analyse the incidence of cutaneous and intestinal colonization, and connection with infections by the organism, in a hospital setting of a C. auris epidemic. METHODS: This was a retrospective study in intensive care units (ICUs) at a 1200-bed Italian hospital. The incidence of cutaneous positive swabs, and cutaneous carriers, for C. auris was compared to that of rectal positive swabs, and intestinal carriers, and both were correlated with C. auris infections. FINDINGS: A total of 399 patients were included. Seventy-seven patients were infected by C. auris. The ratio of C. auris positive skin swabs from screening in ICUs was 24%. The ratio obtained from infected patients and intestinal C. auris carriers was 49.1%, likewise rectal swabs from a similar cohort of patients (P = 0.373). Of this cohort, 39.7% and 5.5% were colonized only in skin and in rectum, respectively, while 54.8% was colonized in both sites. Of skin swabs, 12.3% and 83.6%, respectively, were always positive and variable over time in single subjects, while 31.5% and 41.1% of rectal swabs were always positive and variable (P = 0.000). Intestinal colonization was associated with increased risk for C. auris urinary infections (P = 0.006). CONCLUSION: C. auris intestinal carriers were fewer than cutaneous carriers, but more continuously colonized. Rectal and skin swabs can be good tools for surveillance, respectively, of colonization and of hygiene measures effectiveness. Urinary tract infections by C. auris appeared to increase along with gastrointestinal presence of the yeast.

Exacerbations and Pseudomonas aeruginosa colonization are associated with altered lung structure and function in primary ciliary dyskinesia.

BACKGROUND: Recurrent bacterial infections of the respiratory tract are one of the major clinical features of the primary ciliary dyskinesia (PCD), a rare genetic disease due to malfunctioning of motile cilia. Chronic infections and persistent inflammation of the respiratory system result in progressive lung disease. Aim of the study was to highlight the main factors associated with clinical, functional and anatomical deterioration in PCD patients. METHODS: We retrospectively analyzed data from 58 patients with PCD, 37 adults and 21 children. The demographic and clinical data, forced expiratory volume at 1 s (FEV1) and forced vital capacity (FVC), sputum microbiology and imaging results (chest CT scores-modified Bhalla) were recorded. Patients were stratified according to the number of exacerbations (< 2/year vs ≥ 2/year) and chronic Pseudomonas aeruginosa (PA) colonization. The possible correlations between lung function and chest CT scores were assessed; we also evaluated the correlation between these parameters and the severity scores for bronchiectasis (BSI, FACED and e-FACED). RESULTS: Chest CT scores showed a significant correlation with FEV1 (p = 0.0002), age (p <  0.0001), BMI (p = 0.0002) and number of lung lobes involved (p <  0.0001). PA colonization had an overall prevalence of 32.6%: no significant difference in FEV1 between PA colonized and non-colonized patients was found (p = 0.70), while chest CT score was significantly worse in chronic PA colonized patients (p = 0.009). Patients with a high number of exacerbation (≥ 2/year) were older (p = 0.01), had lower FEV1 (p = 0.03), greater number of lobes involved (p < 0.001) and worse CT score than patients with low number of exacerbations (p = 0.001); they also had higher prevalence of PA chronic bronchial infection (33.3% versus 13.6%, p = 0.10). Multivariable linear regression analyses adjusted for gender, age and BMI showed positive associations between PA colonization and number of exacerbations with severity of disease (number of lobes involved, CT score, BSI, FACED, and e-FACED). CONCLUSIONS: In our PCD population the number of exacerbations (≥ 2/year) and PA colonization were the two most relevant factors associated with severity of disease.

Emerging ciliopathies: are respiratory cilia compromised in Usher syndrome?

PURPOSE: Usher syndrome is a ciliopathy involving photoreceptors and cochlear hair cells (sensory cilia): since sensory and motor ciliopathies can overlap, we analysed the respiratory cilia (motile) in 17 patients affected by Usher syndrome and 18 healthy control subject. PATIENTS AND METHODS: We studied the mucociliary transport time with the saccharine test, ciliary motility and ultrastructure of respiratory cilia obtained by nasal brushing; we also recorded the classical respiratory function values by spirometry. RESULTS: All enrolled subjects showed normal respiratory function values. The mean mucociliary transport time with saccharine was 22.33 ± 17.96 min, which is in the range of normal values. The mean ciliary beat frequency of all subjects was 8.81 ± 2.18 Hz, which is a value approaching the lower physiological limit. None of the classical ciliary alterations characterizing the "ciliary primary dyskinesia" was detected, although two patients showed alterations in number and arrangement of peripheral microtubules and one patient had abnormal ciliary roots. CONCLUSIONS: Respiratory cilia in Usher patients don't seem to have evident ultrastructural alterations, as expected, but the fact that the ciliary motility appeared slightly reduced could emphasize that a rigid distinction between sensory and motor ciliopathies may not reflect what really occurs.

Effects of demethylfruticuline A and fruticuline A from Salvia corrugata Vahl. on biofilm production in vitro by multiresistant strains of Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis.

In this study, demethylfruticuline A (dfA) and fruticuline A (fA), two quinones representing the major diterpenoid components of the exudate produced by the aerial parts of Salvia corrugata, were assessed for their ability to modify surface characteristics, such as hydrophobicity, and to inhibit synthesis of biofilm in vitro by multiresistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. Five strains of S. aureus (three meticillin-resistant and two meticillin-susceptible), five strains of S. epidermidis (four meticillin-resistant and one meticillin-susceptible) and eight vancomycin-resistant E. faecalis, all recently isolated from clinical specimens and capable of slime production, were studied. fA decrease by at least two-fold the hydrophobic properties of the S. aureus cell membrane but did not affect S. epidermidis or E. faecalis. Biofilm formation on polystyrene plates was quantified spectrophotometrically by established methodologies. Inhibition of biofilm formation was also confirmed by the Congo red agar plate assay. dfA and fA were more effective against S. aureus strains (>70% effect at subinhibitory concentrations) than against S. epidermidis in inhibiting slime synthesis. Against E. faecalis, dfA at subinhibitory concentration induced an inhibition of biofilm production of ca. 60%; fA was less active and more strain-dependent. Moreover, the two compounds were shown to possess chelating activity on divalent and trivalent metal cations. Interactions of fA and dfA with bacteria could be very complex, possibly being species-specific, and could depend not only on inhibition of exopolysaccharide synthesis but also on their chelating activity and on changes in the microorganism's surface, including cell hydrophobicity.

Lung function in beta-thalassemia patients: a longitudinal study.

Patients with beta-thalassemia often present with a restrictive pattern at pulmonary function tests (PFTs) due to several pathogenetic factors. However, the long-term evolution is unknown. We performed a longitudinal study of pulmonary function in asymptomatic, non-smoking patients with beta-thalassemia major and intermedia. We looked for temporal changes in lung function and characteristics that would predict the development of PFT abnormalities. In 1996, 18 patients with major beta-thalassemia (9 males and 9 females; age range: 18-35 years) and 11 patients with intermediate beta-thalassemia (5 males and 6 females; age range: 25-51 years) underwent clinical assessment and PFT, including body plethysmography and gas transfer study (carbon monoxide diffusion capacity, DL(CO)). Patients were reassessed in 2003. An echocardiographic evaluation was also obtained to exclude pulmonary hypertension. In 55.5% of major and 45.4% of intermediate beta-thalassemia patients, a restrictive pattern was found in 1996; in 2003 only 38.8 and 27.2% of patients, respectively, exhibited total lung capacities below the predicted values. DL(CO) was unchanged in both groups of patients, being reduced in 5 thalassemia major patients and within the normal range in intermediate patients. We conclude that asymptomatic patients with beta-thalassemia have a high prevalence of PFT abnormalities, but without significant increases over time. An improvement may be observed when good control of the iron balance is reached with optimal chelation therapy.

Effects of salmeterol on cilia and mucus in COPD and pneumonia patients.

The present study was performed to evaluate the effects of salmeterol xynaphoate on ciliary beat frequency (CBF) of nasal epithelium and on rheological parameters of tracheobronchial mucus. We studied 10 steady-state COPD patients, eight patients with community-acquired pneumonia and eight healthy subjects as controls. They underwent a nasal brushing of the inferior turbinate to study the CBF in basal conditions and following application of salmeterol at 10(-5), 10(-6), 10(-7) and 10(-8) M concentrations directly to the epithelial samples. We also collected sputum samples, in COPD patients only, by the technique for "protected expectoration" for the rheological assessment in basal conditions and following addition of salmeterol at 10(-5), 10(-6), 10(-7) and 10(-8) M concentrations. Only samples with basal viscosity values higher than 2000 mPa/s were admitted. Our results confirmed previous studies that demonstrate a ciliostimulating effect induced by salmeterol. The mean basal CBF was 11.18 +/- 0.75 Hz in control subjects, while the pathological subjects showed a markedly lower basal values: 8.64 +/- 0.88 Hz (p = 0.000) and 8.83 +/- 0.68 Hz (p = 0.000), in COPD and pneumonia patients, respectively. Salmeterol induced ciliostimulation in both patients groups as well as the healthy controls. The maximum increase in CBF, highly significant, was obtained at 10(-6) M concentrations of salmeterol, while this effect decreased at lower concentrations. Regarding the action of salmeterol on rheological parameters, a direct effect of salmeterol on mucus cannot been demonstrated and the described beneficial clinical effects on mucociliary clearance occurring in vivo are probably related to an indirect effect of stimulation of ciliary beat. This preliminary study suggests that, in addition to COPD, salmeterol could be a useful therapeutic agent in pneumonia also, for its positive effect on ciliary movement other than bronchodilation, but this finding needs further investigations.

Nasal ciliary beat after insertion of septo-valvular splints.

OBJECTIVE: At present, endonasal paraseptal splints are devices frequently employed in rhinosurgery. We evaluated the local tolerance of a newly shaped device, the Guastella/Mantovani splint (G/M-SVS), with respect to the physiological mechanism of mucociliary clearance. STUDY DESIGN AND SETTING: The study involved 20 patients who underwent septoplasty and/or turbinoplasty or other nasal surgical procedures. A sample of ciliated cells was obtained by nasal brushing and was examined ex vivo to determine the ciliary beat frequency (CBF) and morphology, before and 15 days after surgery. RESULTS: Before surgery the mean CBF was 10.87 Hz +/- 0.56 Hz and when splints were removed it was 10.25 Hz +/- 1.9 Hz. Morphological evaluation of the ciliary motion after surgery demonstrated a normal, coordinated beat. CONCLUSIONS: The G/M-SVS does not appear to interfere with the physiological mechanism of mucociliary clearance since CBF remain within a normal range. SIGNIFICANCE: This is the first study that demonstrates an optimal tolerability and safety of the septo-valvular splints on nasal mucosa.

Effects of zafirlukast on bronchial asthma and allergic rhinitis.

Asthma and allergic rhinitis are common conditions, occurring with increasing prevalence and frequently coexist. In both conditions histamine and cysteinil leukotrienes are important pathogenic inflammatory mediators. We evaluated the effects of the leukotriene receptor antagonist zafirlukast, 20mg administered twice daily for 2 weeks, in patients with allergic rhinitis and bronchial asthma during the grass pollen season. Patients underwent skin prick testing, spirometry, rhinomanometry, mucus transport test with saccharine, nasal epithelial brushing to study ciliary beat and, finally, nasal lavage.Thirty-five subjects completed the study. At the end of the study period, zafirlukast significantly reduced asthma and rhinitis symptoms (P< or =0.05); FEV(1) values were unchanged (P=0.10), whereas nasal resistances showed a decrease following treatment (P=0.01). Ciliary beat frequency (CBF) also improved (P=0.00), although mucociliary transport showed no improvement (P=0.87). The number of eosinophils in nasal lavage fluid decreased (P=0.00) while that of neutrophils was unchanged (P=0.09). These positive effects suggest that zafirlukast may be usefully employed in the treatment of both bronchial asthma, as previously demonstrated, and allergic rhinitis.

Nasal ciliary function and ultrastructure in Down syndrome.

OBJECTIVES/HYPOTHESIS: To investigate the in vivo nasal ciliary beat and the ciliary ultrastructure in Down syndrome because, although in this condition an increased susceptibility to respiratory tract infections has been reported by several authors, the nature of this phenomenon is not fully understood. STUDY DESIGN: Experimental study of 18 subjects with Down syndrome and 18 healthy control subjects. METHODS: Ciliary beat frequency (CBF) was measured on samples of ciliated epithelium obtained from the inferior nasal turbinate; a further brushing for ultrastructural analysis was performed only in subjects showing a CBF reduction or a ciliary movement alteration. RESULTS: The mean CBF in the group with Down syndrome was 7 +/- 2.82 Hz, and in the control subjects it was 10.94 +/- 0.65 Hz. In the same 66.6% of subjects with Down syndrome, we observed a fibrillatory movement of cilia and no metachronicity was present. Moreover, in 14 subjects with Down syndrome as hyperproduction of mucus was present. Ultrastructural evaluation at transmission election microscopy instead revealed a normal architecture of cilia. CONCLUSION: We attribute the nature of the mucociliary defect in Down syndrome to recurrent respiratory tract infections causing changes in mucus properties as in rheological parameters and not to a primitive defect of cilia.

Cytokine gene expression and T-cell proliferative responses in lymph node mononuclear cells from children with early stage human immunodeficiency virus infection.

BACKGROUND AND OBJECTIVES: The immunologic events taking place in secondary lymphoid tissue from children with early stage human immunodeficiency virus (HIV) infection are poorly understood. The aim of this study was to investigate cytokine gene expression and proliferative responses in lymph node (LN) biopsies from five children with early stage HIV infection, in the context of LN morphology and viral load. DESIGN AND METHODS: The design of the study was approved by the local Ethical Committee. Cytokine gene expression was studied in LN biopsies and in paired peripheral blood (PB) samples from HIV-infected children by reverse transcriptase-polymerase chain reaction. T-cell proliferation was assessed by 3H-thymidine incorporation. Viral burden in germinal centers was assessed by video densitometric analysis following immunohistochemical staining for HIV p24. RESULTS: Interleukin (IL)-2, IL-4 and IL-5 mRNA were not detected in any LN or PB sample from HIV-infected children. Interferon (IFN)-gamma mRNA was found only in CD8+ cells. IL-12 p35, IL-10, transforming growth factor-(TGF)-beta1, regulated on activation normal T-cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and IL-16 transcripts were detected in all samples. Proliferation of LN and PB mononuclear cells to polyclonal mitogens and soluble (recall and HIV-related) antigens was impaired as compared with the responses in a group of age-matched healthy controls. INTERPRETATION AND CONCLUSIONS: Changes in cytokine gene expression and T-cell proliferative responses are already detectable in lymph nodes from HIV-infected children at an early stage of disease.

Audiological evaluation in adult beta-thalassemia major patients under regular chelation treatment.

With the improved life expectation of beta -thalassemia major patients, new clinical problems, such as hearing damage, must be evaluated. Fifty-seven patients (32 F, 25 M; age range 17-32 years) have been studied to define risk factors for development of sensorineural hearing loss. All patients with beta -thalassemia major received daily chelation therapy with subcutaneous injection of desferrioxamine (30-50 mgkg(-1)per day). We performed an otological visit and pure tone audiometry as well as impedance; patients were followed for 3 years. Four patients with a conductive hearing loss were excluded; 66.6% had a normal audiogram; 22.8% had a slight sensorineural deficit (

Beta-thalassemia and pulmonary function.

BACKGROUND AND OBJECTIVE: The survival of patients with beta-thalassemia major and intermedia has improved considerably. This has focused attention on the long-term sequelae of the disease itself and its treatment. The effect of hemosiderosis in major organs (heart, liver, etc) are well-recognized, but the pathophysiology of any lung damage is less clearly understood. We studied lung function changes in 32 patients with beta-thalassemia. DESIGN AND METHODS: Respiratory function tests, CO diffusion and arterial blood gas analysis were performed on 19 patients with beta-thalassemia major (9 F, 10 M) and 13 with beta-thalassemia intermedia (6 M, 7 F). All investigations were performed 24 hours before the patients received a blood transfusion or when they were in a stable state hematologic condition. Echocardiography was performed in all patients and the ejection fraction was employed as a measure of cardiac function. RESULTS: No patient had clinical signs of pulmonary dysfunction. Pulmonary function tests, however, showed a reduction of all main parameters (TLC, FVC, FEV1 and RV) in most patients with beta-thalassemia major, indicating a restrictive type of dysfunction. The pulmonary function of patients with beta-thalassemia intermedia seemed to be preserved. Arterial blood gas values were within the normal range, while in some subjects CO diffusion approached the lower limits of normality. There was no evidence that the observed abnormalities in pulmonary function were secondary to congestive heart failure. INTERPRETATION AND CONCLUSIONS: Iron deposition due to repeated blood transfusions may play a central role in determining lung alterations although the majority of patients are well chelated, suggesting that more than one causal mechanisms could be involved.

Identification of immunodominant epitopes in the filamentous hemagglutinin of Bordetella pertussis.

The filamentous hemagglutinin (FHA) of Bordetella pertussis is a principal adhesin, which plays a key role in the colonization of the upper respiratory tract. FHA is also a protective antigen, which has been incorporated in the new generation of acellular vaccines against whooping cough. The protein is synthesized as a large 367-kDa precursor, which is then processed into a 220-kDa secreted polypeptide. To optimize the use of this protein for vaccine purposes it would be helpful to define the regions encompassing immunodominant epitopes. Twelve recombinant plasmids have been generated encoding fusion proteins between fragments of the matured-secreted 220-kDa form of FHA and the vector-encoded phage MS2 polymerase. Protein extracts of the resulting recombinant clones have been tested for reactivity with sera from 20 patients convalescent from whooping cough, and two human standard sera. The results indicate the presence of an immunodominant B cell epitope in the polypeptide coded by a 1-kb DNA fragment encompassing positions 5781-6800 of the published sequence. These results suggest that the identified fragment should be conserved in the formulation of vaccines against pertussis.

The role of chemotherapy in polymorphonuclear phagocytosis in pneumonia.

The efficacy of the host defense system is a determining factor for the outcome of antimicrobial events in infected patients. The neutrophil granulocyte plays a key role in the lung's defense against bacterial invasion and in the absence of a sufficient attraction of functionally intact neutrophils in the lung, following bacterial challenge, severe pulmonary infection may result. The involvement of phagocytes in pneumonia is well known: infiltration of lung parenchyma by neutrophils occurs within a short time in response to infection and is followed by an influx of monocytes. We investigated the effects of antimicrobial therapy in pneumonia on polymorphonuclear neutrophil (PMN) phagocytosis.

Stable expression of pertussis toxin in Bordetella bronchiseptica under the control of a tightly regulated promoter.

Pertussis toxin (PT) is an essential component of accellular vaccines against whooping cough. However, the industrial production of PT from Bordetella pertussis is impaired by slow growth and poor yields. To overcome these problems, we have constructed a minitransposon containing the tox operon under the control of a tightly regulated promoter responsive to an aromatic inducer. The expression cassettes have been integrated into the chromosome of Bordetella bronchiseptica 5376 and ATCC 10580 bvg. Five recombinant clones containing the tox operon under the control of the Psal promoter, which is activated by the product of nahR, were further characterized. The recombinant clones expressed PT after only 3 h of induction with sodium salicylate at levels similar to those of B. pertussis grown for 24 h. The stability of the engineered phenotype was 100% after 72 h of growth without selective pressure. The growth pattern was not modified either under noninducing conditions or in the presence of the inducer at low concentrations, suggesting that strain performance would not be affected in bioreactors when uncoupled from gene expression. Recombinant PT, which was localized mainly in the periplasm, was purified by affinity chromatography. The recombinant protein was immunologically indistinguishable from wild-type PT and retained its biological activity as determined by the CHO cell-clustering test. These recombinant clones appear to be useful tools for the cost-effective production of PT under conditions of improved biosafety, as demonstrated by the inducible expression of PT uncoupled from the bacterial biomass in a nonvirulent and fast-growing B. bronchiseptica background.

Bacterial adherence in smokers and non-smokers.

Bacterial adherence is thought to be a first important step in the pathogenesis of infection. It is now recognized that bacteria bind to and colonize mucosal surfaces in a highly selective manner via a lock- and key mechanism with complementary receptors on the mucosal surfaces of the host. We studied adherence to buccal cells of a panel of potential respiratory pathogens as Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa in 18 smokers and 18 healthy non-smokers. Our results show an increased pneumococcal adherence in smokers compared to that of non-smokers and this may explain the role of smoking as a risk factor in the susceptibility to bacterial pneumonia. The other bacterial species tested do not differ in their adhesion values and probably require previous damage of the mucosa before adhesion 1997 The Italian Pharmacological Society.

Human T leukaemia virus type 1 (HTLV-1) specific T-helper cell response: clonal fluctuations and repertoire heterogeneity.

The naive T-helper (Th) repertoire specific for HTLV-1 envelope (env) has been examined on antigen specific T-cell lines and clones from non-immune individuals. Clonal heterogeneity was determined by analysing the T-cell receptor (TCR) Vbeta gene usage and by sequencing the hypervariable regions of the TCR genes. Fluctuations in the V beta gene usage were determined by comparing the TCR Vbeta gene profiles of T-cell lines at different times. We found that a diverse repertoire for HTLV-1 env could be triggered in vitro. Diverse Vbeta genes were used by the same line tested at different times, suggesting that clonal composition of an antigen-specific T-cell line is not constant in vitro. Clones in fact may be up- and down-regulated and clonotypes undetectable at one time point can emerge upon subsequent restimulation. Therefore evaluation of the clonal composition of a T-cell line gives a snapshot of the dominant clones at the time of analysis, and does not tell the whole picture of the antigen-specific ensemble. Furthermore, by sequencing the TCR genes, we identified clones with identical Vbeta gene usage which differed in hypervariable regions (CDR3), indicating their derivation from independent precursors and contributing to overall clonal heterogeneity. If these data can be extended to HTLV-1-infected patients studied in vivo, the Th cell repertoire specific for HTLV-1 env may prove very heterogenous, with important implications for vaccine development.