Long-term Pulmonary Sequelae Research Articles

Adipose-derived stromal vascular fraction cells to treat long-term pulmonary sequelae of coronavirus disease 2019: 12-month follow-up

Background aimsLong coronavirus disease (COVID) is estimated to occur in up to 20% of patients with coronavirus disease 2019 (COVID-19) infections, with many having persistent pulmonary symptoms. Mesenchymal stromal cells (MSCs) have been shown to have powerful immunomodulatory and anti-fibrotic properties. Autologous adipose-derived (AD) stromal vascular fraction (SVF) contains MSC and other healing cell components and can be obtained by small-volume lipoaspiration and administered on the same day. This study was designed to study the safety of AD SVF infused intravenously to treat the pulmonary symptoms of long COVID. MethodsFive subjects with persistent cough and dyspnea after hospitalization and subsequent discharge for COVID-19 pneumonia were treated with 40 million intravenous autologous AD SVF cells and followed for 12 months, to include with pulmonary function tests and computed tomography scans of the lung. ResultsSVF infusion was safe, with no significant adverse events related to the infusion out to 12 months. Four subjects had improvements in pulmonary symptoms, pulmonary function tests, and computed tomography scans, with some improvement noted as soon as 1 month after SVF treatment. ConclusionsIt is not possible to distinguish between naturally occurring improvement or improvement caused by SVF treatment in this small, uncontrolled study. However, the results support further study of autologous AD SVF as a treatment for long COVID.

Impact of post-COVID-19 lung damage on pulmonary function, exercise tolerance and quality of life in Indian subjects.

After recovery from COVID-19, there is data to suggest potential long-term pulmonary sequelae and associated impairment of functional capacity. This cross-sectional study was designed to assess the impact on respiratory function in a cohort of Indian subjects. Subjects who had recovered from COVID-19 were recruited. Clinical symptoms, pulmonary function test results, 6-minute walk test (6MWT) results, St George's Respiratory questionnaire (SGRQ) and chest radiographs were obtained. Information on the COVID-19 illness during hospitalization, baseline laboratory biomarkers and the disease severity categories as outlined by WHO (asymptomatic, mild, moderate, severe and critical), were retrieved from the hospital records. The 'COVID pneumonia'(WHO category moderate, severe & critical) group was compared with the 'Mild COVID' (WHO category mild) group and likewise, the WHO category moderate and the WHO category severe/critical groups were compared. In 207 subjects, whose mean age was 48.7 years were assessed after an average of 63 days from onset of symptom, 35% had TLC< 80% (restrictive defect), 8.3% had FEV1/FVC<70% (obstructive defect) and 44.4% had diminished DLCO<80% (diffusing capacity). The 'COVID-19 pneumonia' group when compared to the 'mild COVID-19' group, had lower FVC% (77.85 VS 88.18; P = 0.001), TLC% (79.48 VS 87.91; P = 0.0002), DLCO% (75.30 VS 89.20; P<0.0001) and DLCO/VA% (105.6 VS 111.8; P = 0.032), decreased minimum oxygen saturation (94.89 VS 97.73; P<0.0001) and more subjects had a drop in saturation of ≥ 4% (21.69% VS 4.84%; P = 0.001) during the 6MWT, and a greater mean total SGRQ score (29.2 VS 11.0; P<0.0001). To our knowledge, this is the first such report on Indian subjects. We have shown that post-COVID-19 lung damage leads to significant impairment of lung function, quality of life and effort tolerance.

Lung Function Trajectories in Mild COVID-19 With 2-year Follow-up.

The long-term pulmonary sequelae of mild coronavirus disease 2019 (COVID-19) remains unknown. In this study, we aimed to characterize lung function trajectories in individuals with mild COVID-19 from preinfection to 2 years postinfection. We reinvited participants 2 years after infection from our matched cohort study of the Copenhagen General Population who had initially been examined 5.4 months after infection. We repeated lung tests and questionnaires. Linear mixed models were used to estimate dynamics in lung volumes in individuals with COVID-19 patients versus uninfected controls over two intervals: from pre-infection to 6 months postinfection and 6 months postinfection to 2 years postinfection. 52 individuals (48.6%) attended the 2-year examination at median 1.9 years (interquartile range, 1.8-2.4) after COVID-19, all with mild infection. Individuals with COVID-19 had an adjusted excess decline in forced expiratory volume in 1 second (FEV1) of 13.0 mL per year (95% confidence interval [CI], -23.5 to -2.5; P = .02) from before infection to 6 months after infection compared to uninfected controls. From 6 to 24 months after infection, they had an excess decline of 7.5 mL per year (95% CI, -25.6-9.6; P = .40). A similar pattern was observed for forced vital capacity (FVC). Participants had a mean increase in diffusing capacity for carbon monoxide (DLco) of 3.33 (SD 7.97) between the 6- and 24-month examination. Our results indicate that mild COVID-19 infection affects lung function at the time of infection with limited recovery 2 years after infection.

Approaches to the Prevention and Treatment of Respiratory Syncytial Virus Infection in Children: Rationale and Progress to Date.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection (LRTI) in children, and is associated with long-term pulmonary sequelae for up to 30 years after infection. The mainstay of RSV management is supportive therapy such as supplemental oxygen. Palivizumab (Synagis™-AstraZeneca), a monoclonal antibody targeting the RSV F protein site II, has been licensed for the prevention of RSV in high-risk groups since 1998. There has been recent promising progress in preventative strategies that include vaccines and long-acting, high-potency monoclonal antibodies. Nirsevimab (Beyfortus™-AstraZeneca/Sanofi), a monoclonal antibody with an extended half-life, has recently been registered in the European Union and granted licensure by the US Food and Drug Administration. Furthermore, a pre-fusion sub-unit protein vaccine has been granted licensure for pregnant women, aimed at protecting their young infants, following established safety and efficacy in clinical trials (Abrysvo™-Pfizer). Also, multiple novel antiviral therapeutic options are in early phase clinical trials. The next few years have the potential to change the landscape of LRTI through improvements in the prevention and management of RSV LRTI. Here, we discuss these new approaches, current research, and clinical trials in novel therapeutics, monoclonal antibodies, and vaccines against RSV infection in infants and children.

Outcomes at 7 Years of Age of Former Very Preterm Neonates with Repeated Surfactant Treatment for Prolonged Respiratory Distress in the Neonatal Period.

This study aimed at evaluating the 7-year outcomes of 118 very preterm newborns (VPNs, gestational age = 26 ± 1.4 w) involved in a randomized controlled trial. They presented neonatal respiratory distress (RDS), requiring ventilation for 14 ± 2 days post-natal age (PNA). A repeated instillation of 200 mg/kg poractant alfa (SURF) did not improve early bronchopulmonary dysplasia, but the SURF infants needed less re-hospitalization than the controls for respiratory problems at 1- and 2-year PNA. There was no growth difference at 7.1 ± 0.3 years between 41 SURF infants and 36 controls (80% of the eligible children), and 7.9% SURF infants vs. 28.6% controls presented asthma (p = 0.021). The children underwent cognitive assessment (WISC IV) and pulmonary function testing (PFT), measuring their spirometry, lung volume, and airway resistance. The spirometry measures showed differences (p < 0.05) between the SURF infants and the controls (mean ± standard deviation (median z-score)) for FEV1 (L/s) (1.188 ± 0.690(-0.803) vs. 1.080 ± 0.243 (-1.446)); FEV1 after betamimetics (1.244 ± 0.183(-0.525) vs. 1.091 ± 0.20(-1.342)); FVC (L) (1.402 ± 0.217 (-0.406) vs. 1.265 ± 0.267 (-1.141)), and FVC after betamimetics (1.452 ± 0.237 (-0.241) vs. 1.279 ± 0.264 (-1.020)). PFT showed no differences in the volumes or airway resistance. The global IQ median (interquartile range) was 89 (82:99) vs. 89 (76:98), with 61% of the children >85 in both groups. Repeated surfactant treatment in VPNs presenting severe RDS led to the attenuation of early lung injuries, with an impact on long-term pulmonary sequelae, without differences in neurodevelopmental outcomes.

Chest CT features and functional correlates of COVID-19 at 3 months and 12 months follow-up

Long-term pulmonary sequelae of Coronavirus 2019 (COVID-19) remain unclear. Thus, we aimed to establish post-COVID-19 temporal changes in chest computed tomography (CT) features of pulmonary fibrosis and to investigate associations with respiratory symptoms and physiological parameters at 3 and 12 months' follow-up. Adult patients who attended our initial COVID-19 follow-up service and developed chest CT features of interstitial lung disease, in addition to cases identified using British Society of Thoracic Imaging codes, were evaluated retrospectively. Clinical data were gathered on respiratory symptoms and physiological parameters at baseline, 3 months, and 12 months. Corresponding chest CT scans were reviewed by two thoracic radiologists. Associations between CT features and functional correlates were estimated using random effects logistic or linear regression adjusted for age, sex and body mass index. In total, 58 patients were assessed. No changes in reticular pattern, honeycombing, traction bronchiectasis/bronchiolectasis index or pulmonary distortion were observed. Subpleural curvilinear lines were associated with lower odds of breathlessness over time. Parenchymal bands were not associated with breathlessness or impaired lung function overall. Based on our results, we conclude that post-COVID-19 chest CT features of irreversible pulmonary fibrosis remain static over time; other features either resolve or remain unchanged. Subpleural curvilinear lines do not correlate with breathlessness. Parenchymal bands are not functionally significant. An awareness of the different potential functional implications of post-COVID-19 chest CT changes is important in the assessment of patients who present with multi-systemic sequelae of COVID-19 infection.

Exosomal miR-17-5p, miR-146a-3p, and miR-223-3p Correlate with Radiologic Sequelae in Survivors of COVID-19-Related Acute Respiratory Distress Syndrome.

We investigated the association between circulating microRNAs (miRNAs) potentially involved in the lung inflammatory process and fibrosis development among COVID-19-related acute respiratory distress syndrome (ARDS) survivors. At 4 ± 2 months from clinical recovery, COVID-19-related ARDS survivors matched for age, sex, and clinical characteristics underwent chest high-resolution computerized tomography (HRCT) and were selected based on imaging pattern evolution into fully recovered (N = normal), pulmonary opacities (PO) and fibrosis-like lesions (FL). Based on the previous literature, we performed plasma miRNA profiling of exosomal miRNAs belonging to the NLRP3-inflammasome platform with validated (miR-17-5p, miR-223-3p) and putative targets (miR-146a-5p), miRNAs involved in the post-transcriptional regulation of acute phase cytokines (miR128-3p, miR3168, miR125b-2-3p, miR106a-5p), miRNAs belonging to the NLRP4-inflammasome platform (miR-141-3p) and miRNAs related to post-transcriptional regulation of the fibrosis process (miR-21-5p). miR-17-5p, miR-223-3p, and miR-146a-5p were significantly down-regulated in patients with FL when compared to patients with PO. miR-146a-5p was also down-regulated in patients with FL than in N. The expression of the remaining miRNAs did not differ by group. In patients with long-term pulmonary radiological sequelae following COVID-19-related ARDS, a down-regulation of miR-17-5p, miR-146a-3p, and miR-223-3p correlated to fibrosis development in patients showing persistent hyper-reactivity to inflammatory stimulation. Our results support the hypothesis that NLRP3-Inflammasome could be implicated in the process of fibrotic evolution of COVID-19-associated ARDS.

Radiological pulmonary sequelae after COVID-19 and correlation with clinical and functional pulmonary evaluation: results of a prospective cohort.

Whether COVID-19 leads to long-term pulmonary sequelae or not remains unknown. The aim of this study was to assess the prevalence of persisting radiological pulmonary fibrotic lesions in patients hospitalized for COVID-19. We conducted a prospective single-center study among patients hospitalized for COVID-19 between March and May 2020. Patients with residual symptoms or admitted into intensive care units were investigated 4months after discharge by a chest CT (CCT) and pulmonary function tests (PFTs). The primary endpoint was the rate of persistent radiological fibrotic lesions after 4months. Secondary endpoints included further CCT evaluation at 9 and 16months, correlation of fibrotic lesions with clinical and PFT evaluation, and assessment of predictive factors. Among the 1151 patients hospitalized for COVID-19, 169 patients performed a CCT at 4months. CCTs showed pulmonary fibrotic lesions in 19% of the patients (32/169). These lesions were persistent at 9months and 16months in 97% (29/30) and 95% of patients (18/19) respectively. There was no significant clinical difference based on dyspnea scale in patients with pulmonary fibrosis. However, PFT evaluation showed significantly decreased diffusing lung capacity for carbon monoxide (p < 0.001) and total lung capacity (p < 0.001) in patients with radiological lesions. In multivariate analysis, the predictive factors of radiological pulmonary fibrotic lesions were pulmonary embolism (OR = 9.0), high-flow oxygen (OR = 6.37), and mechanical ventilation (OR = 3.49). At 4months, 19% of patients investigated after hospitalization for COVID-19 had radiological pulmonary fibrotic lesions; they persisted up to 16months. Whether COVID-19 leads to long-term pulmonary sequelae or not remains unknown. The aim of this study was to assess the prevalence of persisting radiological pulmonary fibrotic lesions in patients hospitalized for COVID-19. The prevalence of persisting lesions after COVID-19 remains unclear. We assessed this prevalence and predictive factors leading to fibrotic lesions in a large cohort. The respiratory clinical impact of these lesions was also assessed. • Nineteen percent of patients hospitalized for COVID-19 had radiological fibrotic lesions at 4months, remaining stable at 16months. • COVID-19 fibrotic lesions did not match any infiltrative lung disease pattern. • COVID-19 fibrotic lesions were associated with pulmonary function test abnormalities but did not lead to clinical respiratory manifestation.

Exosomal miRNAs targeting NLRP3 inflammasome platform are associated with radiologic sequelae in survivors of COVID-19-associated acute respiratory distress syndrome

Background: There is limited understanding of the pathophysiology of post-acute pulmonary sequelae in COVID-19-associated acute respiratory distress syndrome (ARDS). We aimed at investigating the association of circulating microRNAs (miRNAs) involved in post-transcriptional regulation of NLRP3-inflammasome pathways and lung radiological features among COVID-19- associated ARDS survivors. Methods: We evaluated COVID-19-associated ARDS survivors at 4±2 months from clinical recovery. Patients were selected based on imaging pattern evolution according to chest high-resolution computerized tomography (HRCT) findings into “fully recovered” (FR), “pulmonary opacities” (PO) and “fibrosis-like lesions” (FL) according to radiological appearance. Plasma miRNA profiling was performed using real time quantitative polymerase chain reaction (RT-qPCR). The exosomal expression of NLRP3 inflammasome related miRNAs (miR-17-5p, miR-223-3p, miR-146a-5p) was evaluated. Results: 31 patients (33% men, mean age 60±6 years, mean BMI 31.1±6.6 Kg/m2) were selected for the present study. No statistically significant differences between FR, PO and FL patterns were observed according to clinical features. NLRP3-inflammasome-related miRNAs such as miR-17-5p, miR-223-3p and miR-146a-5p were significantly up-regulated in patients with PO when compared to patients with FL. miR-146a-5p was also up-regulated in patients with FL than in FR. Conclusions: In patients with long-term pulmonary radiological sequelae following COVID71 19- associated ARDS, a down-regulation of miRNAs inhibiting NLRP3 (miR-17-5p, miR-146a72 3p and miR-223-3p) correlated to fibrosis development in patients showing persistent hyper-reactivity to inflammatory stimulation. NLRP3-Inflammasome-related miRNAs could be a possible therapeutic target to prevent the fibrotic evolution of COVID-19-associated ARDS.

Pulmonary Vascular Phenotypes of Prematurity: The Path to Precision Medicine

Pulmonary hypertension (PH) is associated with significant morbidities and high mortality in preterm infants, yet mechanisms contributing to the pathogenesis of PH, the impact of early pulmonary vascular disease (PVD) on the risk for BPD, the role for PH-targeted drug therapies, and long-term pulmonary vascular sequelae remain poorly understood. PVD is not a homogeneous disease, rather, PVD in the setting of prematurity includes various phenotypes as based on underlying pathophysiology, the severity of associated PH, the timing of disease onset, its contribution to hemodynamic and respiratory status, late outcomes, and other features. As with term newborns, severe hypoxemia with acute respiratory failure (HRF) in preterm infants can be due to marked elevation of pulmonary artery pressure with extrapulmonary shunt, traditionally referred to as persistent pulmonary hypertension of the newborn (PPHN). Transient and less severe levels of PH can also be observed during the early transition after birth without evidence of severe HRF, representing physiologic PH or delayed pulmonary vascular transition in preterm infants. Importantly, echocardiographic evidence of early PH has been strongly associated with the subsequent development of bronchopulmonary dysplasia (BPD), late PH, and chronic respiratory disease during infancy and early childhood. Late PH beyond the first postnatal months in preterm in neonates with established BPD is further associated with poor outcomes, especially as related to BPD severity. In addition, echocardiographic signs of PVD can further persist throughout childhood and may lead to chronic PH of variable severity and cardiac maldevelopment in prematurely born young adults. This review discusses the importance of characterizing diverse pulmonary vascular phenotypes in preterm infants to better guide clinical care and research, and to enhance the development of more precise therapeutic strategies to optimize early and late outcomes of preterm infants.

Review and Update of Active and Passive Immunization Against Respiratory Syncytial Virus.

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection (LRTI) in children, causing approximately 3.6 million hospitalizations per year, and has been associated with long-term pulmonary sequelae for up to 30years after infection, yet preventative strategies and active treatment options remain elusive. The associated morbidity and healthcare related costs could be decreased substantially with the development of these much-needed medications. After an initial false start in the development of an RSV vaccine, gradual progress is now being made with the development of multiple vaccine candidates using numerous different mechanisms of action. Furthermore, nirsevimab, a new monoclonal antibody for the prevention of RSV, has recently been registered in the European Union. New novel treatments for RSV infection are also in the pipeline, which would provide the clinician with much needed ammunition in the management of the acute disease. The next few years have the potential to change the landscape of LRTI forever through the prevention and management of RSV LRTI and thereby decrease the mortality and morbidity associated with it. In this review, we discuss these new approaches, current research, and clinical trials in monoclonal antibody and vaccine development against RSV.

Long-term effects of COVID-19 on lungs and the clinical relevance: a 6-month prospective cohort study.

Background: We aimed to explore the prevalence of prolonged symptoms, pulmonary impairments and residual disease on chest tomography (CT) in COVID-19 patients at 6months after acute illness. Methods: In this prospective, single-center study, hospitalized patients with radiologically and laboratory-confirmed COVID-19 were included. Results: A high proportion of the 116 patients reported persistent symptoms (n=54; 46.6%). On follow-up CT, 33 patients (28.4%) demonstrated residual disease. Multivariate analyses revealed that only neutrophil-to-lymphocyte ratio was an independent predictor for residual disease. Conclusion: Hospitalized patients with mild/moderate COVID-19 still had persistent symptoms and were prone to develop long-term pulmonary sequelae on chest CT. However, it did not have a significant effect on long-term pulmonary functions.

Pulmonary sequelae of SARS-CoV-2 infection and factors associated with persistent abnormal lung function at six months after infection: Prospective cohort study.

Information on the long-term pulmonary sequelae following SARS-CoV-2 infection is limited. Prospective cohort study of hospitalized and non-hospitalized adult patients age >18 with documented SARS-CoV-2 infection by RT-PCR three months prior to enrolment between June and December 2020. Participants underwent full pulmonary function test (PFT), cardiopulmonary exercise testing at 3 months and 6 months. Primary outcome was mean differences of forced vital capacity (FVC), diffuse capacity of lung for carbon monoxide (DLCO), and oxygen consumption (VO2) at 6 vs. 3 months. Secondary outcomes were respiratory outcomes classified into 5 clinical groups-no lung disease, resolved lung disease, persistent lung disease, PFT abnormalities attributable to pre-existing lung disease or other factors, and mild PFT abnormalities of uncertain clinical significance. Fifty-one, 30 hospitalized and 21 non-hospitalized, participants were included. Median age was 51 years; 20 (39.2%) were female. Mean (±SD) percent predicted values of FVC, DLCO and VO2 at 3 vs 6-month-visits were 96.2 ± 15.6 vs. 97.6 ± 15.5, 73.74 ±18 vs. 78.5 ± 15.5, and 75.5 ± 18.9 vs. 76.1 ± 21.5, respectively. Nineteen (37%) patients had physiologic and/or radiographic evidence of lung disease at 3 months with eight (15.7%) continuing to have persistent disease at 6 months. History of diabetes, hypertension, ICU admission and elevated D-Dimer levels were associated with persistent lung disease at 6 months. Persistent lung disease at 6 months post SARS-CoV-2 infection exists. Changes of lung function between 3- and 6-months are not significant. A longer follow-up is required to determine long-term prognosis.

Long-Term Pulmonary Dysfunction by Hyperoxia Exposure during Severe Viral Lower Respiratory Tract Infection in Mice.

Viral-induced lower respiratory tract infection (LRTI), mainly by respiratory syncytial virus (RSV), causes a major health burden among young children and has been associated with long-term respiratory dysfunction. Children with severe viral LRTI are frequently treated with oxygen therapy, hypothetically posing an additional risk factor for pulmonary sequelae. The main goal of this study was to determine the effect of concurrent hyperoxia exposure during the acute phase of viral LRTI on long-term pulmonary outcome. As an experimental model for severe RSV LRTI in infants, C57Bl/6J mice received an intranasal inoculation with the pneumonia virus of mice J3666 strain at post-natal day 7, and were subsequently exposed to hyperoxia (85% O2) or normoxia (21% O2) from post-natal day 10 to 17 during the acute phase of disease. Long-term outcomes, including lung function and structural development, were assessed 3 weeks post-inoculation at post-natal day 28. Compared to normoxic conditions, hyperoxia exposure in PVM-inoculated mice induced a transient growth arrest without subsequent catchup growth, as well as a long-term increase in airway resistance. This hyperoxia-induced pulmonary dysfunction was not associated with developmental changes to the airway or lung structure. These findings suggest that hyperoxia exposure during viral LRTI at young age may aggravate subsequent long-term pulmonary sequelae. Further research is needed to investigate the specific mechanisms underlying this alteration to pulmonary function.

Structural and Functional Pulmonary Assessment in Severe COVID-19 Survivors at 12 Months after Discharge.

Long-term pulmonary sequelae in COVID-19 patients are currently under investigation worldwide. Potential relationships between blood sampling and functional and radiological findings are crucial to guide the follow-up. In this study, we collected and evaluated clinical status, namely symptoms and patients’ reported outcome, pulmonary function tests (PFT), laboratory tests, and radiological findings at 3- and 12-months post-discharge in patients admitted between 25 February and 2 May 2020, and who survived severe COVID-19 pneumonia. A history of chronic pulmonary disease or COVID-19-unrelated complications were used as exclusion criteria. Unenhanced CTs were analyzed quantitatively (compromising lung volume %) and qualitatively, with main patterns of: ground-glass opacity (GGO), consolidation, and reticular configuration. Patients were subsequently divided into groups based on their radiological trends and according to the evolution in the percentage of compromised lung volume. At 12 months post-discharge, seventy-one patients showed significantly improved laboratory tests and PFT. Among them, 63 patients also underwent CT examination: all patients with negative CT findings at three months (n = 14) had negative CT also at 12 months; among the 49/63 patients presenting CT alterations at three months, 1/49 (2%) normalized, 40/49 (82%) improved, 7/49 (14%) remained stably abnormal, and 1/49 (2%) worsened. D-dimer values were low in patients with normal CT and higher in cases with improved or stably abnormal CT (median values 213 vs. 329 vs. 1000 ng/mL, respectively). The overall compromised lung volume was reduced compared with three months post-discharge (12.3 vs. 14.4%, p < 0.001). In stably abnormal CT, the main pulmonary pattern changed, showing a reduction in GGO and an increase in reticular configuration. To summarize, PFT are normal in most COVID-19 survivors 12 months post-discharge, but CT structural abnormalities persist (although sensibly improved over time) and are associated with higher D-dimer values.

Post-COVID-19 sequelae of the respiratory system. A single-centre experience reporting the compromise of the airway, alveolar and vascular components.

The long-term sequelae of COVID-19 have now become more common and appreciable. The SARS-CoV-2 virus can cause a variety of infectious and non-infectious pulmonary complications. The purpose of this study is to raise awareness about post-COVID-19 pulmonary sequelae, both infectious and non-infectious, in this geographical area. A retrospective study was conducted from July 1st 2020 to December 20th 2020. A total of 1200 patients were evaluated, with 83 suffering from post-COVID-19 pulmonary complications. The patients' mean age was 62 years (IQR 55-69), with 63 (75.9%) being male. The most common co-morbid illnesses were hypertension (49, 59%) and diabetes (45, 54.2%). The majority of them (37, 44.6%) had severe COVID-19, followed by critical COVID-19 (33, 39.8%). There was no statistically significant difference in recurrence of respiratory symptoms or duration of current illness between non-severe, severe, and critical COVID-19 patients. Non-infectious complications were observed in the majority of patients (n=76, 91.5%), including organizing pneumonia/ground glass opacities in 71 (88%) patients, fibrosis in 44 (55%), pulmonary embolism in 10 (12.5%), pneumomediastinum in 6 (7.4%) and pneumothorax in 7 (8.6%). Infective complications (25, 30.1%) included aspergillus infection in 10 (12.0%) and bacterial infection in 5 (8.47%), with more gram-negative infections and one patient developing Mycobacterium tuberculosis. Post COVID-19 mortality was 11 (13.3%). The long-term pulmonary sequelae of COVID-19 are not rare. Cryptogenic organizing pneumonia, ground glass opacities, and fibrosis were common post-COVID-19 sequelae in our patients. This necessitates frequent close monitoring of these patients in order to initiate early appropriate management and prevent further morbidity and eventual mortality.

INVASIVE PULMONARY FUSARIOSIS WITH SUPERIMPOSED HISTOPLASMOSIS IN AN IMMUNOCOMPETENT HOST

INVASIVE PULMONARY FUSARIOSIS WITH SUPERIMPOSED HISTOPLASMOSIS IN AN IMMUNOCOMPETENT HOST

PD-1 and ICOS counter-regulate tissue resident regulatory T cell development and IL-10 production during flu.

Regulatory T cells that express the transcription factor Foxp3 (Treg cells) are a highly heterogenous population of immunoregulatory cells critical for maintaining immune homeostasis and preventing immunopathology during infections. Tissue resident Treg (TR-Treg) cells are maintained within nonlymphoid tissues and have been shown to suppress proinflammatory tissue resident T cell responses and promote tissue repair. Human populations are repetitively exposed to influenza infections and lung tissue resident effector T cell responses are associated with flu-induced long-term pulmonary sequelae. The kinetics of TR-Treg cell development and molecular features of TR-Treg cells during repeated and/or long-term flu infections are unclear. Utilizing a Foxp3RFP/IL-10GFP dual reporter mouse model along with intravascular fluorescent in vivo labeling, we characterized the TR-Treg cell responses to repetitive heterosubtypic influenza infections. We found lung tissue resident Treg cells accumulated and expressed high levels of co-inhibitory and co-stimulatory receptors post primary and secondary infections. Blockade of PD-1 or ICOS signaling reveals that PD-1 and ICOS signaling pathways counter-regulate TR-Treg cell expansion and IL-10 production, during secondary influenza infection. Furthermore, the virus-specific TR-Treg cell response displayed distinct kinetics, when compared to conventional CD4+ tissue resident memory T cells, during secondary flu infection. Our results provide insight into the tissue resident Foxp3+ regulatory T cell response during repetitive flu infections, which may be applicable to other respiratory infectious diseases such as tuberculosis and COVID.

Long-term Lung Abnormalities Associated with COVID-19 Pneumonia.

In the third year of the SARS-CoV-2 pandemic, much has been learned about the long- term effect of COVID-19 pneumonia on the lungs. Approximately one-third of patients with moderate-to-severe pneumonia, especially those requiring intensive care therapy or mechanical ventilation, have residual abnormalities on chest CT one year after presentation. Abnormalities range from parenchymal bands to bronchial dilation to frank fibrosis. Less is known about the long-term pulmonary vascular sequelae, but there appears to be a persistent, increased risk of venothromboembolic events in a small cohort of patients. Finally, the associated histologic abnormalities resulting from SARS- CoV-2 infection are similar to those of patients with other causes of acute lung injury.

Effects of SARS-CoV-2 Infection on Pulmonary Function Tests and Exercise Tolerance.

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to cause long-term pulmonary sequelae. Objects: The aim of this study was to evaluate the consequences of the SARS-CoV-2 infection on pulmonary function and on the 6-min walk test related to the severity of the disease. Methods: A cross-sectional study was conducted at the “Policlinico Tor Vergata” Academic Hospital (Rome, Italy), including 75 patients evaluated in post-COVID clinics at the Respiratory Units between November 2020 and September 2021. Complete pulmonary function tests, 6-min walk tests and persistence of symptoms were performed. Results: Of the 75 subjects, 23 had mild, 16 moderate, 26 severe and 10 very severe COVID-19, classified according to WHO. Very severe patients had a lower FVC (100 ± 10%pr) compared to the other groups (116 ± 16%pr, 116 ± 13%pr, 122 ± 20%pr from mild to severe; p < 0.05) and a lower TLC (94 ± 13%pr) compared to the others (102 ± 10%pr, 108 ± 15%pr, 108 ± 12%pr from mild to severe; p < 0.05). DLco and DLco/VA were similar among groups. At the 6MWT, distance, rest and nadir SpO2 were similar among groups, but all groups presented a significant decrease in SpO2 from rest to nadir (Rest SpO2: 97.0 ± 1.0% vs. Nadir SpO2: 93.6 ± 2.7%, p < 0.01). A positive correlation was found between desaturation and delta SpO2 (rest—nadir) (R: 0.29, p < 0.05) and the Distance Desaturation Product (R: 0.39, p < 0.01). Conclusions: These results showed that, although the PFTs are within the normal range, there is still a mild restrictive spirometric pattern after six months in very severe subjects. Moreover, the only persistent pathological sequalae of SARS-CoV-2 infection were a mild desaturation at 6MWT, despite the severity of the infection.