Monocyte-driven atypical cytokine storm and aberrant neutrophil activation as key mediators of COVID-19 disease severity

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

Intensive care unit-acquired weakness

When critically ill, a severe weakness of the limbs and respiratory muscles often develops with a prolonged stay in the intensive care unit (ICU), a condition vaguely termed intensive care unit-acquired weakness (ICUAW). Many of these patients have serious nerve and muscle injury. This syndrome is most often seen in surviving critically ill patients with sepsis or extensive inflammatory response which results in increased duration of mechanical ventilation and hospital length of stay. Patients with ICUAW often do not fully recover and the disability will seriously impact on their quality of life. In this chapter we discuss the current knowledge on the pathophysiology and risk factors of ICUAW. Tools to diagnose ICUAW, how to separate ICUAW from other disorders, and which possible treatment strategies can be employed are also described. ICUAW is finally receiving the attention it deserves and the expectation is that it can be better understood and prevented.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

The Sick and the Weak: Neuropathies/Myopathies in the Critically Ill

Critical illness polyneuropathies (CIP) and myopathies (CIM) are common complications of critical illness. Several weakness syndromes are summarized under the term intensive care unit-acquired weakness (ICUAW). We propose a classification of different ICUAW forms (CIM, CIP, sepsis-induced, steroid-denervation myopathy) and pathophysiological mechanisms from clinical and animal model data. Triggers include sepsis, mechanical ventilation, muscle unloading, steroid treatment, or denervation. Some ICUAW forms require stringent diagnostic features; CIM is marked by membrane hypoexcitability, severe atrophy, preferential myosin loss, ultrastructural alterations, and inadequate autophagy activation while myopathies in pure sepsis do not reproduce marked myosin loss. Reduced membrane excitability results from depolarization and ion channel dysfunction. Mitochondrial dysfunction contributes to energy-dependent processes. Ubiquitin proteasome and calpain activation trigger muscle proteolysis and atrophy while protein synthesis is impaired. Myosin loss is more pronounced than actin loss in CIM. Protein quality control is altered by inadequate autophagy. Ca(2+) dysregulation is present through altered Ca(2+) homeostasis. We highlight clinical hallmarks, trigger factors, and potential mechanisms from human studies and animal models that allow separation of risk factors that may trigger distinct mechanisms contributing to weakness. During critical illness, altered inflammatory (cytokines) and metabolic pathways deteriorate muscle function. ICUAW prevention/treatment is limited, e.g., tight glycemic control, delaying nutrition, and early mobilization. Future challenges include identification of primary/secondary events during the time course of critical illness, the interplay between membrane excitability, bioenergetic failure and differential proteolysis, and finding new therapeutic targets by help of tailored animal models.

Retinitis pigmentosa and bronchiectasis: a case report on a rare association suggestive of a common underlying primary ciliary dyskinesia (PCD)

We describe a case of retinitis pigmentosa, associated with bronchiectasis, as the first sign of primary ciliary dyskinesia (PCD). Only a few cases were described in the literature and the association of both diseases is not obvious at first sight, although a common ciliary dysfunction of both respiratory epithelium and photoreceptors of the retina seems to be the common factor. It is important to recognize the association and to question patients with retinitis pigmentosa about their respiratory functions, because an early diagnosis of PCD can prevent recurrent infections and development of bronchiectasis with daily physiotherapy.

[An unusual interstitial pneumonitis]

We report the case of a twenty-six-years-old patient who developed acute silicosis after only five years of professional exposure. He also succeedingly presented in the course of the disease progressive massive fibrosis, rest hypoxia, and eventually spontaneous pneumothorax. Monopulmonary transplantation was finally successfully performed.

Usefulness of FDG-PET to diagnose intravascular lymphoma with encephalopathy and renal involvement

Intravascular lymphoma (IVL) is a rare subtype of extranodal diffuse large B-cell lymphoma. It is characterized by proliferation of neoplastic Lymphoid cells almost exclusively within the lumina of small blood vessels. It can affect virtually every organ system. Due to its rarity and its diverse and heterogeneous clinical presentation, diagnosis is difficult and often made post-mortem. When diagnosed early, it is, however, potentially treatable. We present a young woman with longstanding constitutional symptoms, positive antinuclear antibody, elevated LDH levels and rapidly progressive encephalopathy. FDG-PET scan showed intense uptake in the renal cortex, which prompted us to perform a kidney biopsy which was compatible with IVL. The value of PET in establishing the diagnosis of this rare disease will be discussed.

[Ground-glass opacity and mixed pulmonary nodules: a new computed tomography semiology of the pulmonary adenocarcinoma]

Recently a new computed tomography semiology of the pulmonary adenocarcinoma was highlighted. Studies on ground-glass nodule and on mixed nodule showed the relation between these radiological images and the different anatomopathological forms of lung adenocarcinoma. Ground-glass opacity can correspond to precancerous lesions and morphological characteristics of nodules are correlated with the prognosis. The presence of spiculation, pleural retraction and air bronchogram is significantly more important in neoplasic lesions. The presence or the apparition of a solid component inside the nodule or the presence of indentation is highly suggestive of adenocarcinoma. A lesion smaller than 20 mm and persistant after 1 month must be, either followed up, or removed by a limited surgical resection. Lesions larger than 20 mm or associated with a solid component must be treated by conventional surgery.

Extracorporeal Membrane Oxygenation: Experience in an Adult Medical ICU

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a technology that can provide extracorporeal gas exchange to patients with severe pulmonary or cardiac dysfunction. We report on our clinical experience with ECMO in critically ill patients.

METHODS

We performed a retrospective analysis of 23 patients treated with ECMO in a medical intensive care unit in a tertiary referral academic centre.

RESULTS

13 patients were considered immunocompetent and 10 were immunocompromised when extracorporeal membrane oxygenation was started. 16 patients presented with acute respiratory distress syndrome (ARDS), 2 patients had intractable cardiac failure, and 5 patients had combined respiratory and cardiac failure. In 16 patients, a veno-venous bypass was constructed; in 7 patients, the initial bypass was venoarterial. 11 patients survived. In 2 patients technical complications were fatal.

CONCLUSIONS

Our data indicate that patients with community-acquired pneumonia and no underlying disease will benefit most from this technique. However, long-term survival is possible in immunocompromised patients. Venoarterial bypass can carry a higher risk for technical complications. Increasing experience apparently also reduces the risk of technical complications.

[Anatomo-clinical confrontation: idiopathic pulmonary fibrosis]

Idiopathic pulmonary fibrosis and pulmonary fibrosis associated with systemic diseases are the most frequent diffuse interstitial pulmonary diseases. They slowly but irrevocably progress towards terminal respiratory failure. They can also be complicated by severe acute respiratory failure and admission in the intensive care unit can be discussed. Despite invasive mechanical ventilation, anti-infectious and immunosuppressive treatments, the disease carries a high mortality rate. We report and discuss the case of a patient with idiopathic, pulmonary fibrosis (UIP) who underwent rapid clinical deterioration.

[Work with visual demands. Assumption of responsibility for optical correction by the employer]

Comparison of visual demands of work in a traditional office to those of work in an office equiped with a screen. Description of problems of vision when focusing the eye to various distances and fixing it in various directions. Range of possibilities for optical correction for work with a screen (monofocal, bifocal, progressive or for reading), specifying among the optical corrections those which are exclusively reserved for this activity and should become the employer's responsibility.

[Information for the patient regarding consent clarification both before and after...]

The provision of information to the patient begins before the consultation. The doctor's duty to inform the patient starts with the consultation and continues until after the medical act. The person responsible to provide information, the kind of information that needs to be provided, the moment when such information needs to be given and proofs that information has been given are all discussed. Valuable information is the basis of informed consent.

[Patient access to the medical file]

A new law regulates the access of the patients to their medical files in Belgium. The authors discuss the implications of this law for everyday medical practice.

[Chronic thoracic pain]

The etiological diagnosis of chronic thoracic pain is wide, from benign mechanical disorders to tumors. Reaching the exact diagnosis in often time consuming. Despite the availability of new techniques of imagery, a meticulous clinical history and physical examination remain mandatory. They will lead the exploration. Idiopathic intercostal neuralgia does not exist.

[Clinical case of the month. An unusual cause of bronchiectasis: primary ciliary dyskinesia]

We report a case of bronchiectasis due to primary ciliary dyskinesia.

Myelin reactive T cells after T cell vaccination in multiple sclerosis: cytokine profile and depletion by additional immunizations

Pathogenic autoreactive T cells can be targeted by T cell vaccination (TCV), a procedure in which patients are immunized with autologous attenuated pathogenic T cells. We reported previously that TCV with myelin basic protein (MBP) reactive T cell clones in multiple sclerosis (MS) patients induced T cell immune responses, resulting in a clonal depletion of MBP reactive T cells in all patients. Five years after TCV, MBP reactive T cells were observed in five out of nine MS patients. These clones had a different clonal origin from those isolated before vaccination. We have studied the cytokine profile, cytotoxicity and epitope specificity of these reappearing clones. Our data indicate that the clones express similar effector functions as those isolated before TCV, suggesting that they also could play a pathogenic role in the disease. We demonstrated that these clones can be depleted by an additional sequence of immunizations. These findings may be relevant to other T cell targeted immunotherapies for MS and other autoimmune diseases.

Cellular and humoral immune responses against autoreactive T cells in multiple sclerosis patients after T cell vaccination

Myelin basic protein (MBP)-reactive T cells may play an important role in the autoimmune pathogenesis of multiple sclerosis (MS). MBP-reactive T cells can be specifically targeted by T cell vaccination, a procedure whereby MS patients are immunized with attenuated autologous MBP reactive T cells. T cell vaccination induces immune responses to the vaccine cells together with a depletion of MBP reactive T cells. Forty-nine MS patients were treated with T cell vaccination in an extended phase I trial to study the safety, immune responses and clinical effects of T cell vaccination. In the present paper the immune responses towards the vaccine cells were characterized. Substantial long-term in vitro proliferative responses were observed in all treated patients. Some patients, immunized with different clones, displayed distinct proliferative reactivity against the various vaccine clones, suggesting unequal immunogenic properties of these clones. Reactive TCRalphabeta(+), CD8(+)and CD4(+)T cells, and to a lesser extent, gammadelta T cells and NK cells were observed to in vitro stimulation with the vaccine cells. A small fraction only of CD8(+)T cells expressed cytolytic and inhibitory anti-clonotypic reactivity against the vaccine cells. Stimulation with the vaccine clones predominantly induced expression of pro-inflammatory cytokines in these mixed cultures, although one vaccine clone consistently induced production of IL-4. CD4(+)T cells are the major cytokine-producing cells in these anti-vaccine lines. We could not detect upregulated antibody responses to the vaccine cells in most patients, although a temporary antibody response was observed in one patient. In conclusion, immunization with attenuated autoreactive T cells induces a complex cellular response specifically targeted at the vaccine cells, but no antibody responses. These data provide further insights into the mechanisms of T cell vaccination and improve our understanding of the complex regulatory networks of autoreactive T cells.

Successful treatment of pulmonary lymphangioleiomyomatosis with progestins: a case report

The diagnostic approach, clinical evolution, and treatment of a patient with primary pulmonary lymphangioleiomyomatosis are reported. This patient presented a restrictive respiratory syndrome resistant to conventional glucocorticoid therapy. The diagnosis, based on clinical and histologic examinations, was confirmed by immunohistochemical localization of one of the desmins, the smooth muscle cell actin, and HMB45 antigen. The patient received treatment with an anti-estrogenic agent (tamoxifen citrate) and high doses of medroxyprogesterone acetate, an antigonadotropic progestin. Respiratory function improved rapidly with clinical relief.

Gammadelta T cell responses to activated T cells in multiple sclerosis patients induced by T cell vaccination

To explore the hypothesis that gammadelta T cells may regulate activated alphabeta T cells, we studied gammadelta T cell responses to alphabeta T cell clones in Multiple Sclerosis (MS) patients who received attenuated autologous autoreactive T cells. We recently conducted a pilot study of T cell vaccination with myelin basic protein reactive T cells in MS. Since T cell vaccination upregulates the anti-vaccine T cell responses, we evaluated gammadelta T cell reactivity towards the vaccine in the vaccinated patients. Lymphocytes were stimulated in vitro with irradiated vaccine cells and the responding lines were checked for the presence of gammadelta T cells. Our data demonstrate that in the majority of vaccinated MS patients gammadelta T cells expand upon stimulation with the vaccine cells. The responding gammadelta T cells were predominantly Vdelta1+/Vgamma1+, and represented diverse clonal origins. The gammadelta T cells could not inhibit in vitro proliferation of the vaccine T cells and displayed low cytotoxic reactivity towards the vaccine clones. However, they produced high levels of IL2, TNFalpha and IL10. These results indicate that gammadelta T cells can be stimulated by activated alphabeta T cells, and that these gammadelta T cell responses are upregulated after T cell vaccination. These findings suggest that gammadelta T cells are involved in peripheral mechanisms to control activated autoreactive T cells.

[Optical correction for presbyopia patients using computer terminals]

The study of the ergonomic conditions of office work with a computer screen, the study of the workstation, the nature of the tasks carried out and the knowledge of the visual possibilities of the user allow various optical corrections to be envisaged for this activity. Indications for monofocal, bifocal, trifocal and progressive lenses are envisaged. Optical corrections designed only for work with a screen are described.

[Protective eyeglasses]

Reminder of the materials used for the manufacture of corrective lenses. Belgian statistics concerning eye accidents at work and European legislation concerning the prevention of eye accidents, personal protective equipment, P.P.E. Eye protection for sports.

Clear cell sarcoma: an extremely rare cause of pleural disease

We present the case of a 36 yr old woman with a persisting complaints of left chest pain. A chest radiograph revealed multiple left pleural thickenings. Classical exploration was negative. Thoracic surgery allowed the subtotal removal of a huge pleural tumour. The histological examination revealed a clear cell sarcoma. The literature on this extremely rare tumour is reviewed.

Cytokine profile of myelin basic protein-reactive T cells in multiple sclerosis and healthy individuals

Myelin basic protein (MBP)-reactive T cells have been implicated in the autoimmune pathogenesis of multiple sclerosis (MS). In this study, we examined the cytokine profile of 531 primary MBP-reactive T-cell lines and 72 independently established clones from 32 patients with MS and 18 healthy controls (NS) by using highly sensitive enzyme-linked immunosorbent assays. An increased number of primary T-cell lines producing interferon-gamma (IFN gamma) and/or interleukin-4 (IL-4) in response to MBP were found in patients with MS compared with controls. No distinct Th1 or Th2 subtypes could be demonstrated among the MBP-reactive clones. IL-4 was more frequently observed among MS-derived clones. Clones derived from MS patients produced increased levels of IL-2, IL-4, tumor necrosis factor-alpha (TNF alpha), IFN gamma, and IL-10, but not IL-6. It is interesting that MBP-reactive T cells from MS patients expressing the disease-associated HLA-DRB1*15 allele produced increased quantities of TNF alpha, a cytokine suggested to play an important role in inflammation and demyelination. When challenged with either MBP or a bacterial superantigen, the clones expressed similar levels of the proinflammatory cytokine IFN gamma. Our study suggests a functional difference in T-cell responses to MBP in patients with MS compared with healthy individuals, and provides further insights into the role of MBP-reactive T cells and their cytokine profile in the inflammatory processes of MS.

[Gallbladder volvulus]

We report two new cases of gallbladder volvulus. This rare condition principally affects elderly patients but is due to a congenital malformation related to the presence of a long mesocyst. Various factors such as kyphoscoliosis, multiparity and peristalsis of neighbouring organs favorise the occurrence of volvulus, the role of lithiasis is debatable. The diagnosis may be suggested on ultrasound but is most often confirmed at laparotomy. Diagnosis should be made rapidly in order to avoid progression towards a potentially fatal secondary peritonitis. Certain clinical elements such as the presence of a "floating mass" on palpation may suggest the diagnosis.

Primary pulmonary hemangiopericytoma: early local recurrence after perioperative rupture of the giant tumor mass (two cases)

We report two recent observations of giant hemangiopericytoma of the lung, one in a 4-year-old child and another in a 65-year-old man. There were no specific clinical signs, but the radiologic appearance was rather characteristic in both cases, as were the histologic findings. Pneumonectomy was carried out, complicated in each case by rupture of the fragile, incomplete pseudocapsule and diffuse dissemination of necrotic tumor tissue in the operative field and opposite bronchial tree. Outcome was fatal in both cases within a few months, with extensive, rapidly growing metastases in the subcutaneous scar tissue of the thoracotomy and in the other lung and in one case with diffuse diaphragmatic and intraabdominal metastases. These two observations will offer some guidelines for better understanding of this rare localization of hemangiopericytoma, its natural history, and its optimal treatment, with special reference to the malignant potential and local recurrence rate.

[Carcinoid tumors of the bronchi. Our experience of these during the last 10 years, with a review of the literature]

We present our experience with 18 bronchial carcinoids, two of those being of atypical histology. Mean age is 44 years, without sex preponderance. Clinical symptoms are poorly specific, with persistent cough and recurrent pneumonia as most frequent features. Carcinoid syndrome was seen in one patient. In 4 patients, the carcinoid tumor was an incidental finding on routine chest X-Ray film. Lack of pathognomonic clinical signs explains the considerable delay in diagnosis, with a mean of 10 months of clinical evAluation. Radiographic patterns are atelectatic lobe consolidation, a solitary coin lesion or a transparent lung field. All patients were submitted to bronchoscopic evaluation and only two endoscopic explorations remained negative, because of their peripheral localizations. In all other cases, there was a typical appearance of "cherry red adenoma". Mediastinal extension was present in 2 cases, while extrathoracic metastases were never found. Whenever possible, surgical resection was performed (16 cases). Two patients got endoscopic extirpation of their tumor. There is one postoperative hospital death. This study was done to gain a better understanding of clinical, diagnostic and pathologic features of bronchial carcinoid tumors, and their implications in terms of therapy and prognosis. The authors discuss clinical, diagnostic and therapeutic aspects of bronchial carcinoids as well as their microscopic appearance and relationship with oat cell carcinoma.