The majority of SARS-CoV-2-specific antibodies in COVID-19 patients with obesity are autoimmune and not neutralizing.

BACKGROUND/OBJECTIVES: Obesity decreases the secretion of SARS-CoV-2-specific IgG antibodies in the blood of COVID-19 patients. How obesity impacts the quality of the antibodies secreted, however, is not understood. Therefore, the objective of this study is to evaluate the presence of neutralizing versus autoimmune antibodies in COVID-19 patients with obesity. SUBJECTS/METHODS: Thirty serum samples from individuals who tested positive for SARS-CoV-2 infection by RT-PCR were collected from inpatient and outpatient settings. Of these, 15 were lean (BMI < 25) and 15 were obese (BMI ≥ 30). Control serum samples were from 30 uninfected individuals, age-, gender-, and BMI-matched, recruited before the current pandemic. Neutralizing and autoimmune antibodies were measured by ELISA. IgG autoimmune antibodies were specific for malondialdehyde (MDA), a marker of oxidative stress and lipid peroxidation, and for adipocyte-derived protein antigens (AD), markers of virus-induced cell death in the obese adipose tissue. RESULTS: SARS-CoV-2 infection induces neutralizing antibodies in all lean but only in few obese COVID-19 patients. SARS-CoV-2 infection also induces anti-MDA and anti-AD autoimmune antibodies more in lean than in obese patients as compared to uninfected controls. Serum levels of these autoimmune antibodies, however, are always higher in obese versus lean COVID-19 patients. Moreover, because the autoimmune antibodies found in serum samples of COVID-19 patients have been correlated with serum levels of C-reactive protein (CRP), a general marker of inflammation, we also evaluated the association of anti-MDA and anti-AD antibodies with serum CRP and found a positive association between CRP and autoimmune antibodies. CONCLUSIONS: Our results highlight the importance of evaluating the quality of the antibody response in COVID-19 patients with obesity, particularly the presence of autoimmune antibodies, and identify biomarkers of self-tolerance breakdown. This is crucial to protect this vulnerable population at higher risk of responding poorly to infection with SARS-CoV-2 than lean controls.

Influence of obesity on serum levels of SARS-CoV-2-specific antibodies in COVID-19 patients.

SARS-CoV-2 (Severe Acute Respiratory Syndrome Corona Virus-2), cause of COVID-19 (Coronavirus Disease of 2019), represents a significant risk to people living with pre-existing conditions associated with exacerbated inflammatory responses and consequent dysfunctional immunity. In this paper, we have evaluated the influence of obesity, a condition associated with chronic systemic inflammation, on the secretion of SARS-CoV-2-specific IgG antibodies in the blood of COVID-19 patients. Our hypothesis is that obesity is associated with reduced amounts of specific IgG antibodies. Results have confirmed our hypothesis and have shown that SARS-CoV-2 IgG antibodies are negatively associated with Body Mass Index (BMI) in COVID-19 obese patients, as expected based on the known influence of obesity on humoral immunity. Antibodies in COVID-19 obese patients are also negatively associated with serum levels of pro-inflammatory and metabolic markers of inflammaging and pulmonary inflammation, such as SAA (serum amyloid A protein), CRP (C-reactive protein), and ferritin, but positively associated with NEFA (nonesterified fatty acids). These results altogether could help to identify an inflammatory signature with strong predictive value for immune dysfunction. Inflammatory markers identified may subsequently be targeted to improve humoral immunity in individuals with obesity and in individuals with other chronic inflammatory conditions.

Predicting Disease Severity and Outcome in COVID-19 Patients: A Review of Multiple Biomarkers.

CONTEXT.­: An abundance of clinical reports focused on specific laboratory parameters have been reported on coronavirus disease 19 (COVID-19), but a systematic analysis synthesizing these findings has not been performed. OBJECTIVE.­: To review and summarize the current available literature on the predictive role of various biomarkers in COVID-19 patients. DATA SOURCES.­: A literature search was performed using databases including PubMed, medRxiv, and bioRxiv. A total of 72 papers were reviewed, including 54 peer-reviewed papers and 18 non-peer-reviewed preprints. CONCLUSIONS.­: Although the markers are considered nonspecific, acute-phase reactants, including C-reactive protein (CRP), ferritin, serum amyloid A (SAA), and procalcitonin, were reported as sensitive markers of acute COVID-19 disease. Significantly elevated white blood cell count; marked lymphopenia; decreased CD3, CD4, or CD8 T-lymphocyte counts; high neutrophil count; thrombocytopenia; and markedly elevated inflammatory biomarkers were associated with severe disease and the risk of developing sepsis with rapid progression. Trends observed by serial laboratory measurements during hospitalization, including progressive decrease of lymphocyte count, thrombocytopenia, elevated CRP, procalcitonin, increased liver enzymes, decreased renal function, and coagulation derangements, were more common in critically ill patient groups and associated with a high incidence of clinical complications. Elevated interleukin 6 level and markedly increased SAA were most often reported in severely and critically ill patients. Indicators of systemic inflammation, such as neutrophil to lymphocyte ratio, systemic immune-inflammation index, or COVID-19 Severity Score, may be used to predict disease severity, outcome, and mortality. Interpretation of the data reported in the studies reviewed here is limited because of the study design (mostly retrospective), limited sample size, and a lack of defined clinical criteria.

A How-to Guide to Building a Robust SARS-CoV-2 Testing Program at a University-Based Health System.

When South Florida became a hot spot for COVID-19 disease in March 2020, we faced an urgent need to develop test capability to detect SARS-CoV-2 infection. We assembled a transdisciplinary team of knowledgeable and dedicated physicians, scientists, technologists, and administrators who rapidly built a multiplatform, polymerase chain reaction- and serology-based detection program, established drive-through facilities, and drafted and implemented guidelines that enabled efficient testing of our patients and employees. This process was extremely complex, due to the limited availability of needed reagents, but outreach to our research scientists and multiple diagnostic laboratory companies, and government officials enabled us to implement both Food and Drug Administration authorized and laboratory-developed testing-based testing protocols. We analyzed our workforce needs and created teams of appropriately skilled and certified workers to safely process patient samples and conduct SARS-CoV-2 testing and contact tracing. We initiated smart test ordering, interfaced all testing platforms with our electronic medical record, and went from zero testing capacity to testing hundreds of health care workers and patients daily, within 3 weeks. We believe our experience can inform the efforts of others when faced with a crisis situation.

Review of Current Advances in Serologic Testing for COVID-19.

OBJECTIVES: To examine and summarize the current literature on serologic methods for the detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: A literature review was performed using searches in databases including PubMed, medRxiv, and bioRxiv. Thirty-two peer-reviewed papers and 23 preprints were examined. RESULTS: The studies included lateral flow immunoassay, enzyme-linked immunosorbent assay, chemiluminescence immunoassay, and neutralizing antibody assays. The use of all major SARS-CoV-2 antigens was demonstrated to have diagnostic value. Assays measuring total antibody reactivity had the highest sensitivity. In addition, all the methods provided opportunities to characterize the humoral immune response by isotype. The combined use of IgM and IgG detection resulted in a higher sensitivity than that observed when detecting either isotype alone. Although IgA was rarely studied, it was also demonstrated to be a sensitive marker of infection, and levels correlated with disease severity and neutralizing activity. CONCLUSIONS: The use of serologic testing, in conjunction with reverse transcription polymerase chain reaction testing, was demonstrated to significantly increase the sensitivity of detection of patients infected with SARS-CoV-2. There was conflicting evidence regarding whether antibody titers correlated with clinical severity. However, preliminary investigations indicated some immunoassays may be a surrogate for the prediction of neutralizing antibody titers and the selection of recovered patients for convalescent serum donation.