Post-COVID Interstitial Lung Disease and Other Lung Sequelae

Distinct type 1 immune networks underlie the severity of restrictive lung disease after COVID-19

The variable origins of persistent breathlessness after coronavirus disease 2019 (COVID-19) have hindered efforts to decipher the immunopathology of lung sequelae. Here we analyzed hundreds of cellular and molecular features in the context of discrete pulmonary phenotypes to define the systemic immune landscape of post-COVID lung disease. Cluster analysis of lung physiology measures highlighted two phenotypes of restrictive lung disease that differed according to their impaired diffusion and severity of fibrosis. Machine learning revealed marked CCR5+CD95+CD8+ T cell perturbations in milder lung disease but attenuated T cell responses hallmarked by elevated CXCL13 in more severe disease. Distinct sets of cells, mediators and autoantibodies distinguished each restrictive phenotype and differed from those of patients without substantial lung involvement. These differences were reflected in divergent T cell-based type 1 networks according to the severity of lung disease. Our findings, which provide an immunological basis for active lung injury versus advanced disease after COVID-19, might offer new targets for treatment.

Use of cardiopulmonary exercise testing to identify mechanisms of exertional symptoms in children with long COVID

BACKGROUND

Little is known about the mechanisms of exercise intolerance and exertional symptoms in children with long COVID. Through utilization of cardiopulmonary exercise testing (CPET), this study is the first of its kind to evaluate exertional symptoms and attempt to identify potential mechanism of long COVID-19 in children.

OBJECTIVE

To determine if CPET will uncover potential reasons for persistent symptoms of long COVID when there is no indication of cardiopulmonary or upper airway disease.

METHODS

We performed a retrospective chart review study involving children 6-17 years of age with symptoms of long COVID at Phoenix Children''s Hospital from January 1, 2021, to June 1, 2022. Symptoms included but were not limited to exercise intolerance, fatigue, shortness of breath, dyspnea on exertion, and chest pain. We recorded any measurable abnormalities present on CPET after comparing it to established normal reference ranges. Range, median, and SD of data points were calculated and p values were determined using the Mann-Whitney U and Fisher's exact test.

RESULTS

Twenty-three children with exertional symptoms consistent with long COVID were identified. The most frequent symptoms reported during exercise include dyspnea on exertion (35%), followed by chest pain (30%) and dizziness (13%). Nearly half of the children (47%) demonstrated decreased exercise capacity with 30% displaying limitations due to deconditioning, 22% limited by body habitus, and 13% due to bronchospasm. Other contributing factors include ventilation to perfusion mismatch and volitional hyperventilation.

CONCLUSION

Decreased aerobic activity due to multiple factors was found in 47% of children with a history of COVID-19. This study illustrates the importance of ongoing research into this phenomenon to elucidate its mechanism and assist physicians in making decisions regarding referral to specialists for further testing.

Long COVID and Lung Involvement: A One-Year Longitudinal, Real-Life Study

Background and Objectives: Long COVID as a condition typically manifests itself three months after the initial onset of SARS-CoV-2 infection, with symptoms persisting for a minimum of two months. The aim of the present research was to identify potential predictors of post-COVID-19 syndrome (long COVID-19) and to evaluate factors associated with the presence of post-COVID-19 interstitial lung disease and functional decline. Materials and Methods: 210 patients hospitalized for confirmed SARS-CoV-2 infections mild, moderate, severe, and critical form have been evaluated at 3, 6 and twelve months. Results: Among them only one has been with a suspicion of interstitial lung disease after one year, the rest had no change in the lung. No risk factor from the baseline/3-month or 6-month evaluations significantly influenced patients' status at 12 months. The longer the duration of hospitalization, the lower the FVC and DLCO were at 3 months, but the longer the duration of hospitalization, the higher the number of symptoms at 3 months and 6 months. In a multivariate linear regression analysis, the number of hospitalization days remained statistically significant only for the number of symptoms at 3 months and 6 months. Conclusions: Long COVID seems to be related to the severity of the initial disease, and among the most persistent. Post-COVID-19 interstitial lung disease does not seem to be a frequent entity, as in our study only 0.5% out of 210 patients had it.

Causal associations between severe COVID-19 and diseases of seven organs: a proteome-wide mendelian randomization study

The coronavirus disease 2019 (COVID-19) pandemic poses an enormous threat to public health worldwide. Many retrospective studies and case reports to date have shown associations between severe COVID-19 and diseases of multi-organs. However, the research on the causal mechanisms behind this phenomenon is neither extensive nor comprehensive. We conducted a proteome-wide Mendelian randomization (MR) study using summary statistics from a Genome-Wide Association Studies (GWAS) of severe COVID-19 and diseases related to seven organs: lung, spleen, liver, heart, kidney, testis, and thyroid, based on the European ancestry. The primary analytical method used is the radial inverse variance-weighted (radial IVW) method, supplemented with the inverse variance-weighted (IVW), weighted-median (WM), MR-Egger methods. Our findings have confirmed the association between severe COVID-19 and multiple organ-related diseases, such as Hypothyroidism, strict autoimmune (HTCBSA), Thyroid disorders (TD), and Graves' disease (GD). And we have also identified certain proteins that are associated with organ-related diseases, such as Superoxide Dismutase 2 (SOD2) and TEK Receptor Tyrosine Kinase (TEK), which are also considered potential drug targets. Phenotype scanning and sensitivity analyses were implemented to consolidate the results for Mendelian randomization. This study provides a compelling foundation for investigating COVID-19 caused diseases in future studies.

Distinct Type 1 Immune Networks Underlie the Severity of Restrictive Lung Disease after COVID-19

The variable etiology of persistent breathlessness after COVID-19 have confounded efforts to decipher the immunopathology of lung sequelae. Here, we analyzed hundreds of cellular and molecular features in the context of discrete pulmonary phenotypes to define the systemic immune landscape of post-COVID lung disease. Cluster analysis of lung physiology measures highlighted two phenotypes of restrictive lung disease that differed by their impaired diffusion and severity of fibrosis. Machine learning revealed marked CCR5+CD95+ CD8+ T-cell perturbations in mild-to-moderate lung disease, but attenuated T-cell responses hallmarked by elevated CXCL13 in more severe disease. Distinct sets of cells, mediators, and autoantibodies distinguished each restrictive phenotype, and differed from those of patients without significant lung involvement. These differences were reflected in divergent T-cell-based type 1 networks according to severity of lung disease. Our findings, which provide an immunological basis for active lung injury versus advanced disease after COVID-19, might offer new targets for treatment.

Risk factors for the development of interstitial lung disease following severe COVID-19 pneumonia and outcomes of systemic corticosteroid therapy: 3-month follow-up

BACKGROUND

We aimed to evaluate the pulmonary involvement status, its related factors, and pulmonary function test (PFT) results in the first month follow-up in patients who were discharged for severe Covid-19 pneumonia, and to assess the efficacy of corticosteroid treatment on these parameters in severe pulmonary involvement patients.

METHODS

We retrospectively analyzed all consecutive patients who applied to our COVID-19 follow-up clinic at the end of the first month of hospital discharge. Functional and radiological differences were compared after 3 months of corticosteroid treatment in severe pulmonary involvement group. Results We analyzed 391 patients with "pulmonary parenchymal involvement" (PPIG) and 162 patients with "normal lung radiology" (NLRG). 122 patients in the PPIG (corticosteroid-required interstitial lung disease group (CRILD)) had severe pulmonary involvement with frequent symptoms and required corticosteroid prescription. Pulmonary involvement was more common in males and elder patients (P<0.001, for both). Being smoker and elderly were associated with a higher risk-ratio in predicting to be in PPIG (OR:2.250 and OR:1.057, respectively). Smokers, male and elderly patients, and HFNO2 support during hospitalization were risk factors for being a patient with CRILD (OR:2.737, OR:4.937, OR:4.756, and OR:2.872, respectively). After a three-months of methylprednisolone medication, a good response was achieved on radiological findings and PFT results in CRILD.

CONCLUSIONS

In conclusion, after severe COVID-19 pneumonia, persistent clinical symptoms and pulmonary parenchymal involvement would be inevitable in elder and smoker patients. Moreover, corticosteroid treatment in patients with severe parenchymal involvement was found to be effective in the improvement of radiological and functional parameters.

The pathophysiology of postacute sequelae of COVID-19 (PASC): Possible role for persistent inflammation

As the SARS-CoV-2-induced pandemic wanes, a substantial number of patients with acute Corona Virus-induced disease (COVID-19 continue to have symptoms for a prolonged time after initial infection. These patients are said to have postacute sequelae of COVID (PASC) or "long COVID". The underlying pathophysiology of this syndrome is poorly understood and likely quite heterogeneous. The role of persistent, possibly deviant inflammation as a major factor in comorbidity is suspected.

Objective

To review data that address the relative importance of inflammation in the pathophysiology spectrum of PASC and to address how this would impact diagnosis and approach to therapy in patients identified as having such inflammatory abnormalities.

Methods

A review of public databases, including PubMed, MeSH, NLM catalog, and clinical trial databases such as clinicaltrials.gov.

Results

The literature supports a prominent role for various forms and types of inflammation in the pathophysiologic spectrum of PASC. Such inflammation can be persistent ant CoV-2-specific responses, new onset autoimmune responses, or a loss of normal immunoregulation resulting in widespread, sustained inflammatory pathologies that can affect both broad constitutional symptoms (such as fatigue, neurocognitive dysfunction, and anxiety/depression) and organ-specific dysfunction and/or failure.

Conclusions

PASC is a significant clinical entity with similarities to and differences from other postviral syndromes. Significant research efforts are ongoing to better understand specific aberrant inflammatory pathways present in individual patients for the purpose of developing and implementing effective therapies and ultimately prophylaxis strategies to prevent the progression of COVID-19 as well as likely future viral illnesses and pandemics.