Cellular and molecular signaling towards T cell immunological self-tolerance

The binding of a cognate antigen to T cell receptor (TCR) complex triggers a series of intracellular events controlling T cell activation, proliferation, and differentiation. Upon TCR engagement, different negative regulatory feedback mechanisms are rapidly activated to counterbalance T cell activation, thus preventing excessive signal propagation and promoting the induction of immunological self-tolerance. Both positive and negative regulatory processes are tightly controlled to ensure the effective elimination of foreign antigens while limiting surrounding tissue damage and autoimmunity. In this context, signals deriving from co-stimulatory molecules (i.e., CD80, CD86), co-inhibitory receptors (PD-1, CTLA-4), the tyrosine phosphatase CD45 and cytokines such as IL-2 synergize with TCR-derived signals to guide T cell fate and differentiation. The balance of these mechanisms is also crucial for the generation of CD4+ Foxp3+ regulatory T cells, a cellular subset involved in the control of immunological self-tolerance. This review provides an overview of the most relevant pathways induced by TCR activation combined with those derived from co-stimulatory and co-inhibitory molecules implicated in the cell-intrinsic modulation of T cell activation. In addition to the latter, we dissected mechanisms responsible for T cell-mediated suppression of immune cell activation through regulatory T cell generation, homeostasis, and effector functions. We also discuss how imbalanced signaling derived from TCR and accessory molecules can contribute to autoimmune disease pathogenesis.

COVID-19 Causes Ferroptosis and Oxidative Stress in Human Endothelial Cells

Oxidative stress and endothelial dysfunction have been shown to play crucial roles in the pathophysiology of COVID-19 (coronavirus disease 2019). On these grounds, we sought to investigate the impact of COVID-19 on lipid peroxidation and ferroptosis in human endothelial cells. We hypothesized that oxidative stress and lipid peroxidation induced by COVID-19 in endothelial cells could be linked to the disease outcome. Thus, we collected serum from COVID-19 patients on hospital admission, and we incubated these sera with human endothelial cells, comparing the effects on the generation of reactive oxygen species (ROS) and lipid peroxidation between patients who survived and patients who did not survive. We found that the serum from non-survivors significantly increased lipid peroxidation. Moreover, serum from non-survivors markedly regulated the expression levels of the main markers of ferroptosis, including GPX4, SLC7A11, FTH1, and SAT1, a response that was rescued by silencing TNFR1 on endothelial cells. Taken together, our data indicate that serum from patients who did not survive COVID-19 triggers lipid peroxidation in human endothelial cells.

Follicular helper T cell signature of replicative exhaustion, apoptosis, and senescence in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent primary antibody deficiency whereby follicular helper T (Tfh) cells fail to establish productive responses with B cells in germinal centers. Here, we analyzed the frequency, phenotype, transcriptome, and function of circulating Tfh (cTfh) cells in CVID patients displaying autoimmunity as an additional phenotype. A group of patients showed a high frequency of cTfh1 cells and a prominent expression of PD-1 and ICOS as well as a cTfh mRNA signature consistent with highly activated, but exhausted, senescent, and apoptotic cells. Plasmatic CXCL13 levels were elevated in this group and positively correlated with cTfh1 cell frequency and PD-1 levels. Monoallelic variants in RTEL1, a telomere length- and DNA repair-related gene, were identified in four patients belonging to this group. Their blood lymphocytes showed shortened telomeres, while their cTfh were more prone to apoptosis. These data point toward a novel pathogenetic mechanism in CVID, whereby alterations in DNA repair and telomere elongation might predispose to antibody deficiency. A Th1, highly activated but exhausted and apoptotic cTfh phenotype was associated with this form of CVID.

Conventional Total Thyroidectomy Using a Novel Single Retractor: Technical Note for Apollo®

Despite the increasingly innovative techniques developed in thyroid surgery to offer patients minimally invasive and scarless interventions, conventional open procedures still account for most of the interventions performed in this field. The surgical incision length has been significantly reduced, from 6-9 cm to 3 cm, and therefore patients perceive the scar to be highly acceptable. In this technical note, we present the use of a new single retractor (APOLLO®; AFS MEDICAL GmbH, Teesdorf, Austria) for conventional open thyroidectomies with intraoperative neuromonitoring. This device offers several advantages: a) better exposure of the surgical field; b) less traction on skin flaps and neck muscles; and c) protection of the skin edges from the heat generated by energy-based devices/coagulating instruments, with consequent better healing.

Glycation of ryanodine receptor in circulating lymphocytes predicts the response to cardiac resynchronization therapy

Finding reliable parameters to identify patients with heart failure (HF) that will respond to cardiac resynchronization therapy (CRT) represents a major challenge. We and others have observed post-translational modifications of Ryanodine Receptor (RyR) in several tissues (including skeletal muscle and circulating lymphocytes) of patients with advanced HF. We designed a prospective study to test the hypothesis that RyR1 glycation in circulating lymphocytes could predict CRT responsiveness in patients with non-ischemic HF. We enrolled 94 patients who underwent CRT and 30 individuals without HF, examining RyR1 glycation in peripheral lymphocytes at enrollment and after 1 year. We found that baseline RyR1 glycation independently predicts CRT response at 1 year after adjusting for age, diabetes, QRS duration and morphology, echocardiographic dyssynchrony, and hypertension. Moreover, RyR1 glycation in circulating lymphocytes significantly correlated with pathologic intracellular calcium leak. Taken together, our data show for the first time that RyR1 glycation in circulating lymphocytes represents a novel biomarker to predict CRT responsiveness.

Portomesenteric vein thrombosis following sleeve gastrectomy: Case report focusing on the role of pathogenetic factors

INTRODUCTION

Sleeve gastrectomy has currently become the most commonly performed bariatric. procedure worldwide according to the last IFSO survey, overtaking gastric bypass with. a share of more than 50% of all primary bariatric-metabolic surgery. Gastric leak, intraluminal bleeding, bleeding from the staple-line and strictures are the most common complications. Portomesenteric vein thrombosis (PMVT)after sleeve gastrectomy is. another complication that has been increasingly reported in case-series in recent.years, although it remains uncommon. In this case report is described an extended portomesenteric vein thrombosis after. sleeve gastrectomy interesting splenic vein too with a favorable course and an. uneventful follow-up. We try to search in this case for pathogenetic factors involved in. this complication.

CASE REPORT

A 42-year old man, with a body mass index (BMI) of 45 kg/m2, with a medical history of Obstructive Sleep Apnea Sindrome (OSAS) underwent laparoscopic sleeve gastrectomy. Early postoperative course was uneventful. Six days after discharge he complained abdominal pain and was admitted at the Emergency Department. A CT scan with intravenous contrast showed an occlusion of the portal vein, of the intrahepatic major branches and an extension to the superior mesenteric vein and the splenic vein. The patient received heparin and oral anticoagulation together with intravenous hydration and proton pump inhibitors. Considering the favourable course the patient was discharged after six days with long-term oral anticoagulation therapy. Anticoagulation with acenocumarol was continued for six months after a CT scan showed resolution of the PMVT without cavernoma. He had no recurrence of symptoms.

DISCUSSION

Porto-mesenteric thrombosis after sleeve gastrectomy is a rare complication but it has been increasingly reported over the last 10 years along with the extensive use of sleeve gastrectomy. Because PMVT is closely associated with sleeve gastrectomy in comparison with other bariatric procedures, we need to investigate what pathogenetic factors are involved in sleeve gastrectomy. Thrombophylic state, prolonged duration of surgery, high levels of pneumoperitoneum, thermal injury of the gastroepiploic vessels during greater curvature dissection, high intragastric pressure, inadequate antithrombotic prophylaxis and delayed mobilization of the patient after surgery have been reported as pathogenetic factors of portmesenteric vein thrombosis. Most of the cases presented in the literature such as our clinical case resolve with medical therapy, although portal vein thrombus extends into the superior mesenteric vein and the splenic vein.

CONCLUSION

Portomesenteric venous thrombosis is a rare but serious complication of bariatric surgery, especially associated with sleeve gastrectomy. Diagnosis is based on CT examination with intravenous contrast, and initial therapy is anticoagulation. Etiologic factors reported in the literature include a long duration of surgery, a high degree of pneumoperitoneum, high intragastric pressure after sleeve gastrectomy and thermal injury to the short gastric vessels and gastroepiploic arcade. Limited operative time, controlled values of pneumoperitoneum, careful dissection with energy device of gastric greater curvature, appropriate prophylaxis with low molecular weight heparin may be useful tools to prevent and limit this complication. Nonetheless we have to search which factors may condition the evolution of an extended PMVT as that described in this case towards resolution or to a further worsening clinical state. Early diagnosis? Correct treatment? Undiscovered patientrelated factors?

Cognitive Impairment in Frail Hypertensive Elderly Patients: Role of Hyperglycemia

Endothelial dysfunction is a key hallmark of hypertension, which is a leading risk factor for cognitive decline in older adults with or without frailty. Similarly, hyperglycemia is known to impair endothelial function and is a predictor of severe cardiovascular outcomes, independent of the presence of diabetes. On these grounds, we designed a study to assess the effects of high-glucose and metformin on brain microvascular endothelial cells (ECs) and on cognitive impairment in frail hypertensive patients. We tested the effects of metformin on high-glucose-induced cell death, cell permeability, and generation of reactive oxygen species in vitro, in human brain microvascular ECs. To investigate the consequences of hyperglycemia and metformin in the clinical scenario, we recruited frail hypertensive patients and we evaluated their Montreal Cognitive Assessment (MoCA) scores, comparing them according to the glycemic status (normoglycemic vs. hyperglycemic) and the use of metformin. We enrolled 376 patients, of which 209 successfully completed the study. We observed a significant correlation between MoCA score and glycemia. We found that hyperglycemic patients treated with metformin had a significantly better MoCA score than hyperglycemic patients treated with insulin (18.32 ± 3.9 vs. 14.94 ± 3.8; p < 0.001). Our in vitro assays confirmed the beneficial effects of metformin on human brain microvascular ECs. To our knowledge, this is the first study correlating MoCA score and glycemia in frail and hypertensive older adults, showing that hyperglycemia aggravates cognitive impairment.

miR-24 targets SARS-CoV-2 co-factor Neuropilin-1 in human brain microvascular endothelial cells: Insights for COVID-19 neurological manifestations

Neuropilin-1 is a transmembrane glycoprotein that has been implicated in several processes including angiogenesis and immunity. Recent evidence has also shown that it is implied in the cellular internalization of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). We hypothesized that specific microRNAs can target Neuropilin-1. By combining bioinformatic and functional approaches, we identified miR-24 as a regulator of Neuropilin-1 transcription. Since Neuropilin-1 has been shown to play a key role in the endothelium-mediated regulation of the blood-brain barrier, we validated miR-24 as a functional modulator of Neuropilin-1 in human brain microvascular endothelial cells (hBMECs), which are the most suitable cell line for an in vitro bloodâ€"brain barrier model.

miR-24 Targets the Transmembrane Glycoprotein Neuropilin-1 in Human Brain Microvascular Endothelial Cells

Neuropilin-1 is a transmembrane glycoprotein that has been implicated in several processes including angiogenesis and immunity. Recent evidence has also shown that it is implied in the cellular internalization of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). We hypothesized that specific microRNAs can target Neuropilin-1. By combining bioinformatic and functional approaches, we identified miR-24 as a regulator of Neuropilin-1 transcription. Since Neuropilin-1 has been shown to play a key role in the endothelium-mediated regulation of the blood-brain barrier, we validated miR-24 as a functional modulator of Neuropilin-1 in human brain microvascular endothelial cells (hBMECs), which are the most suitable cell line for an in vitro blood-brain barrier model.

miR-98 Regulates TMPRSS2 Expression in Human Endothelial Cells: Key Implications for COVID-19

The two main co-factors needed by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to enter human cells are angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). Here, we focused on the study of microRNAs that specifically target TMPRSS2. Through a bioinformatic approach, we identified miR-98-5p as a suitable candidate. Since we and others have shown that endothelial cells play a pivotal role in the pathogenesis of the coronavirus disease 2019 (COVID-19), we mechanistically validated miR-98-5p as a regulator of TMPRSS2 transcription in two different human endothelial cell types, derived from the lung and from the umbilical vein. Taken together, our findings indicate that TMPRSS2 represents a valid target in COVID-19 treatment, which may be achieved by specific non-coding-RNA approaches.

Percutaneous lung abscess drainage: revisiting the old gold standard

Lung abscess is defined as the necrosis of lung tissue with cavity formation due to varied etiology. The treatment of lung abscesses is medical involving antibiotics and chest physiotherapy. The failure of medical line of management requires an invasive surgical or percutaneous approach for drainage and control of infection. While the literature is ample regarding the surgical approach, it is rather scarce on the percutaneous approach. The percutaneous drainage has been most studied with computed tomography guidance. With our case series we describe to the treatment of lung abscesses non-responsive to medical management, by a bedside minimally invasive ultrasound or fluoroscopy guided percutaneous drainage approach.

Cardiomyocyte-derived exosomal microRNA-92a mediates post-ischemic myofibroblast activation both in vitro and ex vivo

Aims

We hypothesize that specific microRNAs (miRNAs) within cardiomyocyte‐derived exosomes play a pivotal role in the phenoconversion of cardiac myofibroblasts following myocardial infarction (MI).

Methods and results

We used an established murine model of MI, obtained in vivo via ligation of the left anterior descending coronary artery. We isolated adult cardiomyocytes and fibroblasts, and we assessed the functional role of cardiomyocyte‐derived exosomes and their molecular cargo in the activation of cardiac fibroblasts. We identified and biologically validated miR‐92a as a transcriptional regulator of mothers against DPP homologues 7 (SMAD7), a known inhibitor of α‐smooth muscle actin (α‐SMA), established marker of myofibroblast activation. We found that miR‐92a was significantly (P < 0.05) upregulated in cardiomyocyte‐derived exosomes and in fibroblasts isolated after MI compared with SHAM conditions (n ≥ 6/group). We tested the activation of myofibroblasts by measuring the expression levels of αSMA, periostin, and collagen. Primary isolated cardiac fibroblasts were activated both when incubated with cardiomyocyte‐derived exosomes isolated from ischemic cardiomyocytes and when cultured in conditioned medium of post‐MI cardiomyocytes, whereas no significant difference was observed following incubation with exosomes or medium from sham cardiomyocytes. These effects were attenuated when an inhibitor of exosome secretion, GW4869 (10 μM for 12 h) was included in the experimental setting. Through means of specific miR‐92a mimic and miR‐92a inhibitor, we also verified the mechanistic contribution of miR‐92a to the activation of cardiac fibroblasts.

Conclusions

Our results indicate for the first time that miR‐92a is transferred to fibroblasts in form of exosomal cargo and is critical for cardiac myofibroblast activation.

Cavitary lung metastasis as relapse of prostate cancer

Prostate cancer is the most common non-cutaneous malignancy diagnosed in men. It usually metastasizes to bone as osteoblastic lesions on radiographs and regional lymph nodes, and uncommonly to lung, liver and brain. Metastatic prostate cancer recurrence after definitive local therapy can occur in any tissue. The role of fine needle aspiration cytology (FNAC) for diagnosis of metastatic malignancies is well established in literature. We describe a 74 years old male, previously treated for localized prostate cancer, admitted to our Department after total body computed tomography revealed multiple irregular lung lesions some of which had an excavated appearance.

Exercise related ventilation dynamics and clinical correlates in patients with fibrotic idiopathic interstitial pneumonias

Assessment of exercise performance is a key component in the management of interstitial lung diseases, as its limitation may occur very early. Aim of the present study was to assess ventilation dynamics in combination with pulse-oximetry changes in 54 clinically stable patients affected by idiopathic pulmonary fibrosis or idiopathic fibrotic nonspecific interstitial pneumonia. Testing was successfully performed with the Spiropalm 6-MWT Hand-held spirometer by the majority of cases (94%). End test oxygen saturation (SpO2) values <88% were common in most of patients (76%), with a mean distance walked of 403 meters. Ventilation significantly increased due to the contribution of the tidal volume and the respiratory frequency (RF). This finding was associated with a decrease of the end of test respiratory reserve (RR), that was <20% in 9 cases (17.6%). Lung function was inversely related to the end of test RF, while a positive correlation occurred with the end of test RR and the estimated maximal voluntary ventilation (MVV). RR was also a predictive factor of declining forced vital capacity and lung diffusion capacity for carbon monoxide (DLCO) over a 6-month period. Further factors of DLCO impairment were low SpO2 and MVV. Comparison with the cardio-pulmonary exercise test (CPET) showed that the 6-MWT end of test RR was inversely related to the CPET-derived peak RF and VE/VCO2 suggesting RR as pivotal in exercise limitation assessment. Our results open challenging perspectives in an unexplored field. Future research will include management of latent respiratory failure and monitoring of disease progression and therapy response.

Current treatment options for latent tuberculosis infection

Treatment of latent tuberculosis infection (LTBI) is a key component in TB control strategies worldwide. However, as people with LTBI are neither symptomatic nor contagious, any screening decision should be weighed carefully against the potential benefit of preventing active disease in those who are known to be at higher risk and are willing to accept therapy for LTBI. This means that a targeted approach is desirable to maximize cost effectiveness and to guarantee patient adherence. We focus on LTBI treatment strategies in patient populations at increased risk of developing active TB, including candidates for treatment with tumor necrosis factor-α blockers. In the last 40 years, isoniazid (INH) has represented the keystone of LTBI therapy across the world. Although INH remains the first therapeutic option, alternative treatments that are effective and associated with increased adherence and economic savings are available. Current recommendations, toxicity, compliance, and cost issues are discussed in detail in this review. A balanced relationship between the patient and healthcare provider could increase adherence, while cost-saving treatment strategies with higher effectiveness, fewer side effects, and of shorter duration should be offered as preferred.

The use of TNF-α blockers in psoriatic arthritis patients with latent tuberculosis infection

Psoriatic arthritis (PsA) is an inflammatory arthropathy associated with skin and/or nail psoriasis. TNF-α is an essential cytokine for the host defense, and its depletion by treatment may facilitate the risk of infections or their reactivation. The aim of this study was to evaluate the efficacy and safety of TNF-α blockers in patients with PsA and concomitant latent tuberculosis infection (LTBI) comparing their outcome with non-infected PsA patients. This is a retrospective study in 321 patients with PsA, attending the Psoriatic Arthritis Clinic at the University Federico II of Naples, who had an inadequate response to DMARDs and started therapy with TNF-α blockers. We identified 40 patients with LTBI, who were included in this study along with 40 not infected PsA patients as control group. At baseline (T0) and every 3 months for 2 years (T2), data concerning PsA activity were registered. All patients underwent chest X-ray every 6 months (or 12 if appropriate). In each group, 22 patients were on etanercept therapy, 14 on adalimumab, and 4 on infliximab. Anti-TNF-α therapy was effective in both group of patients, and no statistically significant differences were found in the analysis of the study variables between the two groups from T0 to T2. No serious adverse events occurred in both groups, and no patient was withdrawn from therapy. Our experience suggests that anti-TNF-α treatment is effective and safe in PsA patients with concomitant LTBI. Therefore, neither LTBI nor chemoprophylaxis seems to influence the course of anti-TNF-α therapy.

Screening and monitoring of latent tubercular infection in patients taking tumor necrosis factor-α blockers for psoriatic arthritis

Patients with arthritis who need treatment with biologics are carefully screened for possible previous exposure to tuberculosis to detect any latent tubercular infection (LTBI). The traditional method of screening for LTBI is not specific, because positivity could also depend on infection by atypical mycobacteria and bacillus Calmette-Guerin vaccination. In addition, the screening does not show high sensitivity, frequently presenting a false negativity because of immunosuppression caused by drugs used for arthritis. Recently, interferon-γ release assays (IGRA) have been used to screen LTBI with more sensitivity and specificity before treatment with anti-tumor necrosis factor-α drugs. Moreover, in our experience, IGRA are potentially useful in monitoring LTBI during biologic therapy.

Angiogenesis in chronic obstructive pulmonary disease: a translational appraisal

Angiogenesis is a crucial component of lung pathophysiology, not only in cancer but also in other disorders, such as chronic obstructive pulmonary disease (COPD). In COPD angiogenesis is definitely able to control and orchestrate the progression of airway remodeling. Herein, we provide several remarkable translational aspects of angiogenesis in COPD, exploring both basic and clinical research in this field. Indeed, we present a number of pro- and anti-angiogenic factors, which can be also used as potential biomarkers to monitor disease progression.

Role of the Quantiferon-TB Test in Ruling Out Pleural Tuberculosis: A Multi-Centre Study

Diagnosing pleural tuberculosis (plTB) might be difficult due to limited sensitivity of conventional microbiology tools. As M. tuberculosis (MTB)-specific T cells are recruited into pleural space in plTB, their detection may provide useful clinical information. To this aim, in addition to standard diagnostic tests, we used the QuantiFERON-TB Gold In-Tube (QFT-IT) test in blood and pleural effusion (PE) samples from 48 patients with clinical suspicion of plTB, 18 (37.5%) of whom had confirmed plTB. Four of them (22.2%) tested positive with a nucleic acid amplification test for MTB. The tuberculin skin test was positive in most confirmed plTB cases (88.9%). Positive QFT-IT tests were significantly more frequent in patients with confirmed plTB, as compared to patients with an alternative diagnosis, both in blood (77.7 vs 36.6%, p=0.006) and in PE samples (83.3% vs 46.6%, p=0.02). In addition, both blood and PE MTB-stimulated IFN-γ levels were significantly higher in plTB patients (p=0.03 and p=0.0049 vs non-plTB, respectively). In blood samples, QFT-IT had 77.8% sensitivity and 63.3% specificity, resulting in 56.0% positive (PPV) and 82.6% negative (NPV) predictive values. On PE, QFT-IT sensitivity was 83.3% and specificity 53.3% (PPV 51.7% and NPV 84.2%). The optimal AUC-derived cut-off for MTB-stimulated pleural IFN-γ level was 3.01 IU/mL (77.8% sensitivity, 80% specificity, PPV 68.4% and NPV 82.8%). These data suggest that QFT-IT might have a role in ruling out plTB in clinical practice.

Usefulness of Ifn-Gamma Release Assays in Clinical Management of Difficult TB Cases: Evidence from Clinical Practice

Performance of T-SPOT.TB™ (TS-TB) and QuantiFERON TB Gold- In tube (QFT-IT) assays was evaluated for detection of M. tuberculosis (Mtb) infection in patients with suspected extra-pulmonary or smear-negative pulmonary tuberculosis (TB) in a low prevalence country. Twenty-one out of 35 patients were affected by active TB. Mtb culture isolation was achieved in 76% of cases. Tuberculin skin testing (TST), TS-TB, and QFT-IT yielded a positive result in 67%, 95% and 81% of cases, respectively. Agreement of interferon-γ release assays and TST was 70% (κ=0.18 for TS-TB; κ=0.46 for QFT-IT). Increased sensitivity of blood assays (>80%) improved diagnostic evaluation of difficult TB cases.

Prevention of tuberculosis in patients taking tumor necrosis factor-alpha blockers

Treatment with tumor necrosis factor-alpha (TNF-alpha) inhibitors increases the risk of tuberculosis (TB) due to reactivation of latent Mycobacterium tuberculosis infection (LTBI). Screening for LTBI is based mainly on the tuberculin skin test (TST), which has several limitations in any patient who is immunosuppressed due to drugs or autoimmune disease. T cell interferon-gamma release assays (IGRA) have been shown to be more specific than TST in immunocompetent patients and potentially represent a new approach for the management of patients taking TNF-alpha blockers. Even if there is no evidence-based literature of IGRA superiority versus TST in this specific clinical setting, some studies suggest blood assays may be helpful in clinical management of these patients, in addition to currently recommended clinical screening for risk factors for LTBI.

IFN-gamma release assays in tuberculosis management in selected high-risk populations

Tuberculosis (TB) is the most deadly infectious disease in the world. TB control relies on passive case findings and targeted treatment of latently infected individuals at high risk of disease progression. Tuberculin skin testing (TST) is conventionally used for detection of TB infection. Recently, blood assays measuring the release of IFN-gamma by TB-specific effector memory T cells have been developed to overcome TST limitations. Overall, IFN-gamma release assays are more specific than TST, more sensitive in detecting active TB and correlate better with TB exposure in immune-competent patients, at least in low-burden settings. There are three US FDA-approved assays commercially available: the ELISpot-based assay T-SPOT.TB (Oxford Immunotech, UK) and two ELISA-based formats, QuantiFERON TB Gold (QFT) and QFT-in tube (Cellestis, Australia). Recent international guidelines and consensus statements recommend the use of IFN-gamma release assays at different levels in TB management. However, conclusive evidence-based information targeting populations at high TB risk, including HIV-infected individuals, children and patient candidates for biotherapy with TNF-alpha blockers, are lacking. The aim of this review is to focus our attention on studies addressing the performance of commercial IFN-gamma release assays in clinical management of TB infection in these highly selected settings to provide a more comprehensive picture of the actual scenario and to identify areas to be investigated further.

Analysis of Mycobacterium tuberculosis-specific CD8 T-cells in patients with active tuberculosis and in individuals with latent infection

CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-γ and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months after therapy to comparable percentages detected in subjects with latent infection. The majority of CD8 T-cells from subjects with latent infection expressed a terminally-differentiated phenotype (CD45RA⁺CCR7⁻). In contrast, tuberculous patients had only 35% of antigen-specific CD8 T-cells expressing this phenotype, while containing higher proportions of cells with an effector memory- and a central memory-like phenotype, and which did not change significantly after therapy. CD8 T-cells from subjects with latent infection showed a codominance of IL-2⁺/IFN-γ⁺ and IL-2⁻/IFN-γ⁺ T-cell populations; interestingly, only the IL-2⁺/IFN-γ⁺ population was reduced or absent in tuberculous patients, highly suggestive of a restricted functional profile of Mycobacterium tuberculosis-specific CD8 T-cells during active disease. These results suggest distinct Mycobacterium tuberculosis specific CD8 T-cell phenotypic and functional signatures between subjects which control infection (subjects with latent infection) and those who do not (patients with active disease).

[Magnetic resonance study of renal function. Preliminary evaluation]

The amount of functioning renal parenchyma can be estimated by MRI by considering the ratio between the mean intensities of cortical and medullar zones of the kidney. Fifty-six patients and 5 healthy volunteers were studied by MRI in our department. Scanning was performed with a superconductive magnet system operating at 0.5 Tesla. Pulse sequence was Spin-Echo with TR 300/TE 30 ms. The cortico-medullary ratio (CMR) and differentiation (CMD) were standardized and related with creatine blood levels. CMR data ranged from 1.05 to 3.00, while CMD data ranged from 0.04 to 0.50. High values (good cortico-medullary contrast) were observed in subjects with normal renal function. Patients with renal diseases had low CMR and CMD, proportionally to the degree of renal failure, as proved by laboratory findings. Our preliminary study seems to demonstrate that MRI is an useful technique in the follow-up of patients with chronic renal disease.

[Role of magnetic resonance in the staging and post-chemotherapeutic follow-up of malignant maxillo-facial tumors]

Ten patients with squamous cell carcinomas located in the maxillo-facial region were studied. In all cases the staging by Computed Tomography (CT) and Magnetic Resonance (MRI) revealed metastatic lesions in stage T3-T4. All patients underwent polichemotherapy before surgery. MRI proved to be more accurate in the staging of tumors in 3 cases only, while in 7 cases both techniques showed the same diagnostic accuracy. In the follow-up, MRI allowed the evaluation of the effect of chemotherapy on the carcinomas: it demonstrated the regression and necrosis of 9 tumors out of 10 (the patients could undergo surgery), and the progression of the tumor in 1 case. The study of bioptic specimens demonstrated the lack of correlation between histological grading of the tumors with MRI signal intensity and T1, T2 relaxation time, as measured by spectroscopy.