Gallbladder polyps ultrasound: what the sonographer needs to know.

Gallbladder polyps are protuberances of the gallbladder wall projecting into the lumen. They are usually incidentally found during abdominal sonography or diagnosed on histopathology of a surgery specimen, with an estimated prevalence of up to 9.5% of patients. Gallbladder polyps are not mobile and do not demonstrate posterior acoustic shadowing; they may be sessile or pedunculated. Gallbladder polyps may be divided into pseudopolyps and true polyps. Pseudopolyps are benign and include cholesterolosis, cholesterinic polyps, inflammatory polyps, and localised adenomyomatosis. True gallbladder polyps can be benign or malignant. Benign polyps are most commonly adenomas, while malignant polyps are adenocarcinomas and metastases. There are also rare types of benign and malignant true gallbladder polyps, including mesenchymal tumours and lymphomas. Ultrasound is the first-choice imaging method for the diagnosis of gallbladder polyps, representing an indispensable tool for ensuring appropriate management. It enables limitation of secondary level investigations and avoidance of unnecessary cholecystectomies.

Not all abolished lung sliding are pneumothorax: the case of a particular lung atelectasis.

INTRODUCTION: Lung ultrasound (LUS) is expanding from the field of emergency medicine, also to the pneumological specialist field, becoming part of the diagnostic procedure of lung consolidation. CASE PRESENTATION: A 78-year-old male was admitted to our emergency department for exertional dyspnea. LUS was performed, thus showing at right hemitorax air interface, A lines pattern, pleural sliding abolished on the whole hemitorax, thus suggesting a pneumothorax, but no evidence of lung point. A scan of lower lung segment showed an absence of the diaphragmatic excursion, suggestive for hemiparalysis of the diaphragm muscle, then confirmed by a subcostal scan. Moreover, at the lower segment of right hemitorax there was mild pleural effusion allowing the visualization of a round-shaped parenchymal consolidation with the absence of air bronchograms. CONCLUSIONS: LUS allowed the visualization of a particular and rare disease such as anthracosis-associated rounded atelectasis, thus leading to a more correct and faster patient management.

Sonographic demonstration of a spontaneous rectus sheath hematoma following a sneeze: a case report and review of the literature.

Spontaneous rectus sheath hematoma (SRSH) is an uncommon cause of acute abdominal pain characterized by bleeding within the rectus sheath; it is a benign condition and, in most cases, it is treated conservatively. Bleeding of the abdominal wall is an unusual condition that is quite challenging to identify promptly and can be easily overlooked during a routine physical examination. In daily practice, anticoagulant therapy is one of the main risk factors for hemorrhagic events. In this respect, we report a rare case of spontaneous hematoma of the abdominal wall (diagnosed and monitored through an ultrasound examination) that arose after sneezing in a patient receiving anticoagulant treatment.

Effects of body composition on the procoagulant imbalance in obese patients.

Obesity is associated with increased thrombotic risk and hypercoagulability whose main driver is an excess of coagulation factor VIII relative to protein C. The aims of this study were to evaluate the association between factor VIII, protein C, factor VIII-to-protein C ratio and bioimpedance parameters of body composition in obese patients. We analysed blood from 69 obese patients and 23 non-obese healthy controls. Plasma levels of factor VIII, protein C, and factor VIII-to-protein C ratio were correlated with total fat, visceral fat, and muscle mass. Compared to controls, obese patients had significantly higher factor VIII (110.5% vs 78.05%, p < 0.001), protein C (120.99% versus 110.51%, p = 0.014), and factor VIII-to-protein C ratio (0.93 versus 0.73, p = 0.002). In obese patients, factor VIII correlated with body-mass index, body fat percentage, muscle mass percentage, and fat-to-muscle ratio, whereas protein C had significant relationships with body fat percentage, muscle mass percentage and fat-to-muscle ratio, but not with body-mass index. Factor VIII-to-protein C ratio > 1 was significantly associated with body-mass index (odds ratio 1.08, 95% CI 1.02 to 1.14) and fat-to-muscle ratio (odds ratio 2.47, 95% CI 1.10 to 5.55). Factor VIII-to-protein C ratio strongly correlated with D-dimer levels in the overall population (rho 0.44, p < 0.001) and obese patients (rho 0.41, p < 0.001). In obese patients, bioimpedance measures of body fat and muscle mass percentage were associated with factor VIII and protein C. Factor VIII-to-protein C ratio was strongly associated with fat-to-muscle ratio and only modestly related to BMI.

Focused ultrasound for the diagnosis of non-palpable endometriotic lesions of the abdominal wall: a not-uncommon surgical complication.

Endometriosis is a benign disease characterized by endometrial glands and stroma outside the endometrial cavity. We reported two cases of endometriosis of the abdominal wall, with subcutaneous and intramuscular localization, that became symptomatic a few years after a cesarean intervention. These cases have a clinical pattern quite similar to cutaneous endometriosis, but they are more difficult to diagnose through physical examination because they are barely palpable. In this sense, coupled with suggestive symptoms, ultrasound examination can confirm the clinical suspicion of endometriosis without the use of computed tomography and/or magnetic resonance imaging.

Mantle cell lymphoma: from ultrasound examination to histological diagnosis.

We report the case of a 42-year-old patient referred to our department for the examination of two large, symmetrical inguinal lumps. The ultrasound examination of the swollen lymph node demonstrated a cortical echogenicity greater than the medullary echogenicity, and the vascularization stop around the cortical zone suggested a pathological pattern of mantle cell lymphoma. In this type of lymphoma, lymphocytes are localized in a mantle zone, inducing a thickening of the lumps. Therefore, for the first time, ultrasound examination detected sonographic vascular features of mantle cell lymphoma, allowing the identification of the disease and suggesting the specific histological diagnosis.

Risk factors associated to bilateral rotator cuff tears.

INTRODUCTION: Overuse, micro-traumas, and impingement, isolated or combined, are the more common etiological factors for rotator cuff tears. Metabolic disorders (diabetes, adiposity, hypercholesterolemia), hypertension, cigarette smoking and a genetic predisposition are considered risk factors. However, no study has compared the prevalence of these risk factors in subjects with bilateral and monolateral tears. HYPOTHESIS: Controlateral tears can be observed in patients with symptomatic monolateral rotator cuff lesions, especially in those with comorbidities. MATERIAL AND METHODS: In patients with symptomatic rotator cuff tear, the controlateral shoulders were evaluated by means of ultrasound imaging. Age, BMI, diabetes, hypercholesterolemia, hypertension, cigarette smoking, work habits were registered. Risk factors in subjects with bilateral tears were compared with those with monolateral lesions. RESULTS: Of the 180 subjects recruited, 69 had a tear in the controlateral shoulder. Higher age and BMI values, heavy repetitive work and diabetes were significantly prevalent in these patients. At multivariate analysis, these factors were independently related to a higher probability to detect bilateral tears. DISCUSSION: Metabolic risk factors are more heavily involved in presence of bilateral rotator cuff tears, in comparison to monolateral. TYPE OF STUDY: Original study. LEVEL OF PROOF: IV.

Ultrasound Shear Wave Elastography for Liver Disease. A Critical Appraisal of the Many Actors on the Stage.

In the last 12 - 18 months nearly all ultrasound manufacturers have arrived to implement ultrasound shear wave elastography modality in their equipment for the assessment of chronic liver disease; the few remaining players are expected to follow in 2016.When all manufacturers rush to a new technology at the same time, it is evident that the clinical demand for this information is of utmost value. Around 1990, there was similar demand for color Doppler ultrasound; high demand for contrast-enhanced ultrasonography was evident at the beginning of this century, and around 2010 demand increased for strain elastography. However, some issues regarding the new shear wave ultrasound technologies must be noted to avoid misuse of the resulting information for clinical decisions. As new articles are expected to appear in 2016 reporting the findings of the new technologies from various companies, we felt that the beginning of this year was the right time to present an appraisal of these issues. We likewise expect that in the meantime EFSUMB will release a new update of the existing guidelines 1 2.The first ultrasound elastography method became available 13 years ago in the form of transient elastography with Fibroscan(®) 3. It was the first technique providing non-invasive quantitive information about the stiffness of the liver and hence regarding the amount of fibrosis in chronic liver disease 3. The innovation was enormous, since a non-invasive modality was finally available to provide findings otherwise achievable only by liver biopsy. In fact, prior to ultrasound elastography, a combination of conventional and Doppler ultrasound parameters were utilized to inform the physician about the presence of cirrhosis and portal hypertension 4. However, skilled operators were required, reproducibility and diagnostic accuracy were suboptimal, and it was not possible to differentiate the pre-cirrhotic stages of fibrosis. All these limitations were substantially improved by transient elastography, performed with Fibroscan(®), a technology dedicated exclusively to liver elastography. Since then, more than 1300 articles dealing with transient elastography have been listed in PubMed, some describing results with more than 10,000 patients 5. The technique has been tested in nearly all liver disease etiologies, with histology as the reference standard. Meta-analysis of data, available in many etiologies 6, showed good performance and reproducibility as well as some situations limiting reliability 5. Thresholds for the different fibrosis stages (F0 to F4) have been provided by many large-scale studies utilizing histology as the reference standard 7. Transient elastography tracks the velocity of shear waves generated by the gentle hit of a piston on the skin, with the resulting compression wave traveling in the liver along its longitudinal axis. The measurement is made in a 4 cm long section of the liver, thus able to average slightly inhomogeneous fibrotic deposition.In 2008 a new modality became available, Acoustic Radiation Force Impulse (ARFI) quantification, and classified by EFSUMB 1 as point shear wave elastography (pSWE), since the speed of the shear wave (perpendicular to the longitudinal axis) is measured in a small region (a "point", few millimeters) at a freely-choosen depth within 8 cm from the skin. This technology was the first to be implemented in a conventional ultrasound scanner by Siemens(®) 8. Several articles have been published regarding this technology, most with the best reference standards 9, some including findings on more than 1000 hepatitis C patients 10 or reporting meta-analysis of data 11. Although the correlation between Siemens pSWE and transient elastography appeared high 12 13, the calculated thresholds for the different fibrosis stages and the stiffness ranges between the two techniques are not superimposable.Interestingly, pSWE appears to provide greater applicability than transient elastography for measuring both liver 13 and spleen stiffness, which is a new application of elastography 14, of interest for the prediction of the degree of portal hypertension 15 16.Nowadays other companies have started producing equipment with pSWE technology, but only very few articles have been published so far, for instance describing the use of Philips(®) equipment, which was the second to provide pSWE. These articles show preliminary good results also in comparison with TE 17 18. Not enough evidence is currently available in the literature about the elastographic performance of the products most recently introduced to the market. Furthermore, with some products the shear wave velocities generated by a single ultrasound acoustic push pulse can be measured in a bidimensional area (a box in the range of 2 - 3 cm per side) rather than in a single small point, producing a so-called bidimensional 2D-SWE 1. The stiffness is depicted in color within the area and refreshing of the measurement occurs every 1 - 2 seconds. Once the best image is acquired, the operator chooses a Region Of Interest (ROI) within the color box, where the mean stiffness is then calculated. 2D-SWE can be performed as a "one shot" technique or as a semi-"real-time" technique for a few seconds (at about 1 frame per second) in order to obtain a stable elastogram. With either technique, there should be no motion/breathing during image acquisition. A bidimensional averaged area should overcome the limitation of pSWE to inadvertently investigate small regions of greater or lesser stiffness than average. A shear wave quality indicator could be useful to provide real-time feedback and optimize placement of the sampling ROIs, a technology recently presented by Toshiba(®), but which is still awaiting validation in the literature.Supersonic Imagine by Aixplorer(®) which works with a different modality of insonation and video analysis compared to the the previously-mentioned three techniques (i. e., transient elastography, pSWE and 2D-SWE), leading to a bidimensional assessment of liver stiffness in real time up to 5 Hz and in larger regions; thus this technique is also termed real-time 2 D SWE. It has been available on the market for a few years 19 20, and many articles have been published showing stiffness values quite similar to those of Fibroscan(®) 21; likewise, defined thresholds based on histological findings have appeared in several articles 19 20 21.After this brief summary of the technological state of the art we would like to mention the following critical issues that we believe every user should note prior to providing liver stiffness reports. · The thresholds obtained from the "oldest" techniques for the various fibrosis stages based on hundreds of patients with histology as reference standard cannot be straightforwardly applied to the new ultrasound elastography techniques, even if based on the same principle (e. g. pSWE). In fact, the different manufacturers apply proprietary patented calculation modes, which might result in slightly to moderately different values. It should be kept in mind that the range for intermediate fibrosis stages (F1 to F3) is quite narrow, in the order of 2 - 3 kilopascal (over a total range spanning 2 to 75 kPa with Fibroscan), so that slightly different differences in outputs could shift the assessment of patients from one stage to another. Comparative studies using phantoms and healthy volunteers, as well as patients, are eagerly awaited. In fact, the equipment might not produce linear correlations of measurements at different degrees of severity of fibrosis. As a theoretical example, some equipment might well correlate in their values with an older technique, such as transient elastography, at low levels of liver fibrosis, but not as well in cases of more advanced fibrosis or vice versa. Consequentely, when elastography data are included in a report, the equipment utilized for the measurement should be clearly specified, and conclusions about the fibrosis stage should be withheld if an insufficient number of comparative studies with solid reference standards are available for that specific equipment.. · Future studies using histology as a reference might be biased in comparison to previous studies, since nowadays fewer patients with chronic hepatitis C or hepatitis B undergo biopsy. In fact, due to wide availability of effective drugs as well as the use of established elastography methods for patients with viral hepatitis, most cases submitted to biopsy today have uncertain etiology or inconsistent and inconclusive clinical data. Therefore, extrapolated thresholds from such inhomogeneous populations applied to more ordinary patients with viral hepatitis might become problematic in the future, although no better solution is currently anticipated. This situation might lead to the adoption of a standard validated elastographic method as reference, but this has to be agreed-upon at an international level.. · Ultrasound elastography embedded in conventional scanners usually allows the choice of where to place the ROI within the color stiffness box and whether to confirm or exclude each single measurement when determining the final value. Thus, the operator has a greater potential to influence the final findings than with Fibroscan®, where these choices are not available. This has to be kept in mind to avoid the possibility that an operator could, even inadvertently, tend to confirm an assumption about that specific patient or to confirm the patient's expectations.. · Quality criteria for the new technologies following transient elastography are absent (depending on the manufacturer) or have not been satisfactorily defined, so that the information potentially inserted in a report cannot currently be judged for its reliability by the clinician.. (ABSTRACT TRUNCATED)

Ultrasound-guided Percutaneous Lavage in the Treatment of Calcific Tendinopathy of Elbow Extensor Tendons: A Case Report.

We report the efficacy of the ultrasound-guided percutaneous treatment in the management of elbow extensor tendons calcific tendinopathy. The ultrasound-guided percutaneous treatment is broadly used with positive results in patients suffering from rotator cuff calcific tendinopathy. However, this interventional method has been reported only in one patient in the medical literature. A 34 years-old female who complained pain, swelling and severe functional limitation of the right elbow was referred to our unit. Elbow radiographs and ultrasound examination showed a soft-fluid calcification above the origin of the extensor tendons. Ultrasound-guided percutaneous treatment was therefore performed. After one year, the patient reported no pain and regained complete range of elbow motion. This method, in well trained hands, is an alternative treatment in the management of the uncommon elbow calcific deposit.

Sarcoidosis exclusion criteria: the “simple truth” for a “complicated diagnosis”.

The differentiation between sarcoidosis and sarcoid-type reactions remains a clinical and histopathologic diagnostic dilemma. A definitive distinction is yet to be determined according to the current literature data. Sarcoid-like tissue reactions with identifiable infectious or other immunogenic antigens, should be classified as non-specific clinical manifestations of a specific disease. The current assignment of this type of reaction under the generic umbrella of “sarcoidosis” is incorrect and may result in the subsequent misinterpretation of the definition of the disease in general. On the other hand, this may lead to clinical studies with incorrectly selected inclusion criteria and, therefore, contradictory statements regarding the epidemiology and pathogenesis of the disease. Thus we propose the introduction of new criteria for exclusion of sarcoidosis as an autonomous disease. Recent trials on patients with probable sarcoidosis have focused on ideal criteria, or have provided information about the genetic and immunological profile of patients with specific infections or other diseases, which manifest themself as sarcoidal granulomas. This could explain the heterogeneous clinical and/or genetic profiles of the reported patients, who in fact were not affected by the autonomous disease “sarcoidosis”. The simplification of the current available data regarding this issue will be of fundamental importance for the correct direction of future studies, whose aim is to unravel the pathogenesis of the immunological cascade in patients with sarcoidosis and sarcoid-like type of reaction. It is expected that the introduction of exclusion criteria will inevitably lead to a change in the approach to diagnosis as well as the fundamental understanding of this mysterious disease, known as sarcoidosis.

Pitfalls of contrast-enhanced ultrasound (CEUS) in the diagnosis of splenic sarcoidosis.

By observing the real-time behavior of focal liver lesions at three vascular phases (arterial, portal-venous, and late), contrast-enhanced ultrasound (CEUS) has been successfully applied to differentiate benign from malignant hepatic nodules. In recent years, numerous studies highlighted the usefulness of CEUS also for other applications such as abdominal trauma, renal, pancreatic, thyroid, and inflammatory bowel diseases, supporting its role even in differentiating benign from malignant splenic nodules. Therefore, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) recently updated the guidelines for the use of ultrasound contrast agents in clinical practice, pointing out the indication to characterize splenic parenchymal inhomogeneity or suspected lesions found on conventional ultrasound (BUS). We describe the case of a patient with a history of colon cancer and finding, at BUS and CEUS, of hypoechoic lesions with a highly suggestive pattern for metastases, subsequently histologically proved to be splenic localizations of a benign and multisystemic granulomatous disease such as sarcoidosis. We therefore reviewed the current literature focusing on the role of CEUS in differentiating benign from malignant splenic lesions, emphasizing on the lack of data and numerical shortage of sarcoidosis derived-lesions in the available studies. We conclude that sarcoidosis remains a diagnosis of exclusion and new studies are needed before defining precise indications of CEUS in these patients.

Immunopathogenesis of sarcoidosis and risk of malignancy: a lost truth?

The hypothesis of a relationship between sarcoidosis and malignancy was firstly formulated in 1972 by Brincker. He documented an association of sarcoid reactions or sarcoidosis with 19 lymphomas and associated malignancies. Based on various epidemiological studies, for more than 20 years sarcoidosis has been considered as a condition at increased risk for cancer, particularly lymphoproliferative disorders. The existence of a sarcoidosis-lymphoma syndrome was therefore proposed, highlighting, as a potential mechanism, the uncontrolled lymphocyte proliferation and mitotic activity. A reduced ability to eliminate an antigen and chronic inflammation have been suggested as triggering events. Leading to a reduced tumor immune surveillance, a diminished myeloid dendritic cells (mDC) function, despite up-regulated co-stimulatory and maturation markers, was also raised as potential mechanism. However, some subsequent studies have questioned the presence of a close association between the two entities and have explained those previously published as the result of selection bias and misclassification. Recently, a Swedish population-based cohort study documented a significant overall excess incidence of cancer among sarcoidosis patients, especially those with multiple hospitalizations or admission in older age, emphasizing again a potential neoplastic risk. Therefore, currently, whether these patients have an increased risk of developing malignant lesions is still debated. Larger and unbiased studies are needed before drawing definite conclusions.

Neoangiogenesis is reduced in chronic tendinopathies of type 2 diabetic patients.

In diabetes, the prevalence of tendon degeneration is increased. As neoangiogenesis is impaired in several diabetic complications, the aim of this study is to evaluate the neovessel formation in tendinopathies. Patients aged > 55 years were selected, and divided in two groups: a) type 2 diabetic patients, and b) non-diabetic subjects. In both groups, those with ultrasound features of tendinopathy were included, and intratendinous vascularisation was estimated by means of Power Doppler. Ultrasound features of tendinopathy were observed in 104 diabetic subjects and in 221 controls. Neovascularisation, with higher Power Doppler scores, was found more frequently in controls, while lower Power Doppler scores were prevalent in diabetic subjects. In subjects with diabetes, tendinopathic features are significantly higher than healthy controls, while the prevalence of neovascularisation inside tendons is less represented.

Platelet rich plasma in tendinopathies: how to explain the failure.

Tendinopathies are very common in athletes and in people practicing sport activities. The experimental evidence that growth factors (GFs), present in platelets, enhance the recruitment, proliferation and differentiation of cells involved in tissue regeneration, has prompted the use of platelet rich plasma (PRP) preparations in the treatment of these diseases. However, at present, a sound demonstration of the clinical efficacy of PRP is still lacking. Several theoretical and practical reasons can explain the failure of the treatment: a) animal experiments have been carried out on normal tendons submitted to surgical lesions, and it is questionable whether these models may best mimic human pathology; b) the pathway of chronic tendinopathies is very complex, involving, besides GFs, many other pathogenetic factors, which operate at different stages of the disease; c) several methods have been used to produce PRP, which can result in a large variation in GF content, and in kinetics of release. Therefore, further research is desirable. As a preliminary step, it is necessary to standardize PRP preparation, and to establish the modalities of its activation and administration. Secondly, prospective, randomized, double-blind studies are needed, selecting subjects with homogenous forms of tendinopathies: load-bearing and non-load-bearing tendons, midportion and insertional tendinopathies, with or without neovascularization. Finally, new strategies in PRP use should be exploited: among them, the association of PRP with autologous stem cells or the administration of selective GFs (fibroblast growth factor, vascular endothelial growth factor, or anti-angiogenic factors), which could be better options in specific situations.

Environment and T regulatory cells in allergy.

The central role of T regulatory cells in the responses against harmless environmental antigens has been confirmed by many studies. Impaired T regulatory cell function is implicated in many pathological conditions, particularly allergic diseases. The "hygiene hypothesis" suggests that infections and infestations may play a protective role for allergy, whereas environmental pollutants favor the development of allergic diseases. Developing countries suffer from a variety of infections and are also facing an increasing diffusion of environmental pollutants. In these countries allergies increase in relation to the spreading use of xenobiotics (pesticides, herbicides, pollution, etc.) with a rate similar to those of developed countries, overcoming the protective effects of infections. We review here the main mechanisms of non-self tolerance, with particular regard to relations between T regulatory cell activity, infections and infestations such as helminthiasis, and exposure to environmental xenobiotics with relevant diffusion in developing countries.

The persistence of allergen exposure favors pulmonary function decline in workers with allergic occupational asthma.

BACKGROUND: In asthmatics, a rapid decline in pulmonary function is observed, likely as a consequence of airways remodeling. Persistence of allergen exposure in patients with occupational asthma (OA) maintains chronic bronchial inflammation, resulting in a more severe lung function decline. Few studies were performed on the effects of allergen exposure cessation. OBJECTIVE: This study aims at evaluating the influence of allergen exposure cessation on respiratory decline in allergic asthmatic workers. METHODS: Two groups of workers with allergic OA were selected. The first group (30 workers) changed job after the diagnosis and was no more exposed to sensitizing allergens, and the second group (28 subjects) did not and, as a consequence of preventive measures in the work place, was exposed to a lower level of allergens. All were treated with conventional therapy, according to GINA protocols. FEV1 changes during a 12-year period were evaluated. RESULTS: Despite pharmacological therapy, the pulmonary function decay slope was steeper in workers continuously exposed to the sensitizing agent (even at reduced level) than in those with a complete cessation of exposure: final FEV1 loss was 512.5 ± 180 ml versus 332.5 ± 108 ml, respectively. The difference became significant after 4 years from the cessation of the exposure. CONCLUSIONS: The study shows that the cessation of the exposure to allergen in the work place appears the most effective measure in limiting pulmonary function decline in asthmatic workers and underlines the importance of allergic risk assessment and control in the management of occupational asthma.

Environmental pollution and asthma.

Clinical evidences and epidemiological studies show that allergic pathologies of the respiratory tract are increasing in the world areas with high pollution impact, demonstrating how many polluting substances favor both allergic sensitization and the bronchial inflammatory changes characteristic of asthma. It has been shown that asthma, as many other diseases, is a complex interaction between genetic predisposition and environmental stimuli that results in clinical expression of various phenotypes of asthma: allergic, intrinsic etc. Many pollutants have such a potential. Diesel exhaust particles (DEP) can favor allergic sensitization, induce acute asthma attacks and increase bronchial reactivity, acting both on allergen, on bronchial mucosa and on immune cells. In fact, DEP can favor B lymphocytes to shift to a production of IgE and T cells to produce Th2 cytokines. Asthma can be also induced by high exposure to many other substances as NO2 and first of all ozone (O3): strong oxidizing substance that is synthesized, in absence of ventilation, by photochemical reaction due to the combination of ultraviolet sun radiation on exhaust gases as NO2 and hydrocarbons. Ozone is abundant in cities with minimal concentration in the morning gradually increasing during the day until maximal levels in the afternoon and then decreasing during the night. Epidemiological studies show that the number of access to hospital for acute asthma and even the use of bronchodilator by asthmatics increase during the high level periods when Ozone constitute almost 90 percent of the total oxidants in the environment. Particulate matter of very small diameter have a crucial role in favoring asthma attacks, and smaller the substance deeper the penetration in the bronchial tree, with an inflammatory reaction in the peripheral bronchial mucosa characterized by increased vessel permeability, mucosal edema, inflammatory mediator production by damaged epithelium and inflammatory cells that determines acutely a high narrowing of the bronchial lumen and in a long period favor airways remodeling and a rapid decline of respiratory function.

T regulatory cells in allergy.

The progressive understanding of the nature and mechanisms of T regulatory (Treg) cells in the last decade has changed the concept of immune tolerance, that is no longer considered as a mere lack of immune reactivity but as a finely regulated process that requires specific activity of cells, adhesion and secreted molecules. Tregs play a key role in maintenance of self-tolerance and induction of tolerance against ubiquitous innocuous non-self antigens, so preventing the onset of autoimmune diseases and allergies. This review will focus on the Treg response in allergy that is characterized by a down-regulation of allergen specific T cell proliferation and inhibition of both Th1 and Th2 cytokines production. Hence, Treg cells suppress allergen-specific Th1 and Th2 cell responses playing an important role in the physiological immune response to allergens. Further, Treg cells are able to suppress IgE production by B lymphocytes and directly or indirectly inhibit the activity of allergic inflammation effector cells, namely eosinophils, basophils and mastcells. Finally, increasing evidence suggests that Treg cells are also implicated in chronicity development of inflammatory diseases. This appears to happen through a fine interaction they entertain with resident tissue cells and has been particularly highlighted in the study of airways remodeling in asthma. The understanding of the mechanisms underlying allergen tolerance has brought new interest in the development of new allergy treatment, able to target Treg cells, both in allergy prevention and in the therapy of established allergy.