Unique immune and inflammatory cytokine profiles may define long COVID syndrome

sMR and PTX3 levels associate with COVID-19 outcome and survival but not with Long COVID

Biomarkers for monitoring COVID-19 disease course are lacking. Study aim was to identify biomarkers associated with disease severity, survival, long-term outcome, and Long COVID. As excessive macrophages activation is a hallmark of COVID-19 and complement activation is key in this, we selected the following proteins involved in these processes: PTX3, C1q, C1-INH, C1s/C1-INH, and sMR. EDTA-plasma concentrations were measured in 215 patients and 47 controls using ELISA. PTX3, sMR, C1-INH, and C1s/C1-INH levels were associated with disease severity. PTX3 and sMR were also associated with survival and long-term immune recovery. Lastly, sMR levels associate with ICU admittance. sMR (AUC 0.85) and PTX3 (AUC 0.78) are good markers for disease severity, especially when used in combination (AUC 0.88). No association between biomarker levels and Long COVID was observed. sMR has not previously been associated with COVID-19 disease severity, ICU admittance or survival and may serve as marker for disease course.

Altered serum concentrations of IL-8, IL-32 and IL-10 in patients with lung impairment 6 months after COVID-19

Post-COVID symptoms are reported in 10-35 % of patients not requiring hospitalization, and in up to 80 % of hospitalized patients and patients with severe disease. The pathogenesis of post-COVID syndrome remains largely unknown. Some evidence suggests that prolonged inflammation has a key role in the pathogenesis of most post-COVID manifestations. We evaluated a panel of inflammatory and immune-mediated cytokines in individuals with altered HRCT features and in patients without any long-term COVID symptoms. Blood samples of 89 adult patients previously hospitalized with COVID-19 were collected and stratified as patients with and without HRCT evidence of fibrotic lung alterations. Serum analyte concentrations of IL-4, IL-2, CXCL10 (IP-10), IL-1β, TNF-α, CCL2 (MCP-1), IL-17A, IL-6, IL-10, IFN-γ, IL-12p70 and TGF-β1 (free active form) were quantified by bead-based multiplex assay. Clinical and functional data were recorded in a database. With the use of machine learning approach, IL-32, IL-8, and IL-10 proved to be associated with the development of HRCT evidence of lung sequelae at follow-up. Direct comparison of cytokine levels in the two groups showed increased levels of IL-32 and decreased levels of IL-8 in patients with lung impairment. After further stratification of patients by severity (severe versus mild/moderate) during hospitalization, IL-10 emerged as the only cytokine showing decreased levels in severe patients. These findings contribute to a better understanding of the immune response and potential prognostic markers in patients with lung sequelae after COVID-19.

Applying Lessons From Rheumatology to Better Understand Long COVID

Long COVID can sometimes be attributed to organ damage and well-characterized pathophysiology, but more often there is no evidence of organ damage or abnormal biomarkers. This is most evident in patients with mild to moderate initial SARS-CoV-2 infection who were not hospitalized. Their persistent symptoms are strikingly similar to those of fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome, including fatigue, post-exertional malaise, myalgias/arthralgias, and sleep and cognitive disturbances in 50% to 100% of cases. Analogous pathophysiologic pathways in fibromyalgia (FM), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and long COVID include host-microbial interactions in the absence of direct tissue invasion and absence of systemic autoimmunity, with evidence for immune dysregulation as well as autonomic, peripheral, and central nervous system dysfunction. Current treatment of long COVID has been based on multidisciplinary management recommended for FM and ME/CFS and has been formalized and made widely available by funding for nationwide long COVID clinics. Long COVID and its treatment should be distinguished by the presence or absence of organ damage. The acknowledged role of patient engagement in research and open dialogue regarding work and disability noted in long COVID may have meaningful impact on patients with FM and ME/CFS. Hopefully, advances in basic long COVID research will aid in understanding FM and ME/CFS, and rheumatologists should thus be involved in such research and patient care.

Predictive Factors and ACE-2 Gene Polymorphisms in Susceptibility to Long COVID-19 Syndrome

Long COVID-19 syndrome is present in 5-10% of patients infected with SARS-CoV-2, and there is still little information on the predisposing factors that lead to its development. The purpose of the study was to evaluate the predictive factors in early symptoms, clinical features and the role of Angiotensin-Converting Enzyme-2 (ACE-2) c.513-1451G>A (rs2106806) and c.15643279T>C (rs6629110) polymorphisms in the susceptibility to developing Long COVID-19 syndrome subsequent to COVID-19 infectionA total of 29 patients who suffered COVID-19 were recruited in a descriptive longitudinal study of two groups: Long COVID-19 (n = 16) and non-Long COVID-19 (n = 13). Early symptoms and clinical features during COVID-19 were classified by a medical service. ACE-2 polymorphisms were genotyped by using a Single Nucleotide Primer Extension (SNPE). Of the early symptoms, fatigue, myalgia and headache showed a high risk of increasing Long COVID-19 susceptibility. Clinical features such as emergency care, SARS-CoV-2 reinfection, previous diseases, respiratory disease and brain fog also had a high risk of increasing Long COVID-19 susceptibility. The A allele in the rs2106806 variant was associated with an odds ratio (OR) of 4.214 (95% CI 2.521-8.853; p < 0.001), and the T allele in the rs6629110 variant was associated with an OR of 3.754 (95% CI 1.785-6.105; p = 0.002) of increasing Long COVID-19 susceptibility. This study shows the risk of ACE-2 polymorphisms, different early symptoms and clinical features during SARS-CoV-2 infection in susceptibility to Long COVID-19.

Predictive Role of Cytokine and Adipokine Panel in Hospitalized COVID-19 Patients: Evaluation of Disease Severity, Survival and Lung Sequelae

Coronavirus disease 2019 (COVID-19) may determine a multisystemic chronic syndrome after resolution of SARS-CoV-2 infection in a significant percentage of patients. Persistent cytokine dysregulation can contribute to long-lasting inflammation and tissue damage, resulting in the diverse, often debilitating symptoms experienced by some patients (so-called long COVID syndrome). The aim of our study was to evaluate the value of a panel of serum biomarkers of severity and prognosis in patients hospitalized for COVID-19 and also as predictive factors for the development of post-COVID lung sequelae after discharge from the hospital. All blood sampling was performed in the first 24 h after admission to the hospital. Serum analyte concentrations of IL-4, IL-2, CXCL10 (IP-10), IL-1β, TNF-α, CCL2 (MCP-1), IL-17A, IL-6, IL-10, IFN-γ, IL-12p70 and TGF-β1 were quantified by bead-based multiplex LEGENDplex™ analysis and commercially available ELISA kits. A total of 108 COVID-19 patients were enrolled in the study. Comparative analysis of these proteins showed higher levels of TGF-β and IL-6 and lower levels of RBP-4 and IL-10 in the severe group. Age, adiponectin, IL-8 and IL-32 resulted as the best predictors for survival. Moreover, IL-1β, IL17A, TNF-α, TGF-β, IL-4 and IL-6 were significantly higher in patients who showed HRCT evidence of fibrotic interstitial alterations at follow-up than patients who did not. The initial inflammatory status of patients on admission to the hospital with COVID-19, as reflected by the present panel of adipose tissue-related biomarkers and cytokines, offered insights into medium-term prognosis.

Altered Tumor Necrosis Factor Response in Neurologic Postacute SARS-CoV-2 Syndrome

Neurologic manifestations of postacute sequelae after SARS-CoV-2 infection (neuro-PASC) are common; however, the underlying drivers of those symptoms remain poorly understood. Prior work has postulated that immune dysregulation leads to ongoing neuroinflammation. We aimed to identify the cytokines involved in that immune dysregulation by comparing 37 plasma cytokine profiles among 20 case patients with neuro-PASC to 20 age- and gender-matched controls. Neuro-PASC cases were defined as individuals with self-reported persistent headache, general malaise, and anosmia or ageusia at least 28 days post-SARS-CoV-2 infection. As a sensitivity analysis, we repeated the main analysis among only participants of Hispanic heritage. In total, 40 specimens were tested. Participants were an average of 43.5 years old (interquartile range 30-52), 20 (50.0%) of whom identified as women. Levels of tumor necrosis factor alpha (TNFα) were 0.76 times lower [95% confidence interval (CI) 0.62-0.94] among cases of neuro-PASC compared with controls, as were levels of C-C motif chemokine 19 (CCL19) (0.67; 95% CI 0.50-0.91), C-C motif chemokine 2 (CCL2) (0.72; 95% CI 0.55-0.95), chemokine interferon-gamma inducible protein 10 (CXCL10) (0.63; 95% CI 0.42-0.96), and chemokine interferon-gamma inducible protein 9 (CXCL9) (0.62; 95% CI 0.38-0.99). Restricting analysis of TNF and CCL19 to participants who identified as Hispanic did not alter results. We noted a reduction in TNFα and down-stream chemokines among patients with neuro-PASC, suggesting an overall immune attenuation.