New study identifies key markers for long-term coronavirus diagnosis

In a recently uploaded preprint*, medRxiv server, International team of researchers conducts large-scale system-level immunological screening of more than 1,000 confirmed COVID-19 patients to identify diagnostic markers for long-term COVID-19 infection was carried out. Analysis using multiple orthogonal detection methods revealed elevated serology and associated memory CD8 as a highlight of Long COVID.⁺ Clonal expansion of T cells is a more reliable and sensitive marker of symptoms than traditional antigen (SARS-CoV-2 RNA and protein) detection approaches.

study: Restrained Memories CD8⁺ T-cell responses drive viral persistence and elevated IgG responses in severe Long COVID patients. Image credit: Lightspring / Shutterstock

*Important Notices: medRxiv has published preliminary scientific reports that have not been peer-reviewed and should therefore not be considered definitive, guide clinical practice or health-related behavior, or be treated as established information. Not.

New coronavirus infection and the need for long-term new coronavirus diagnosis

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the coronavirus disease 2019 (COVID-19) virus pandemic, one of the worst viral pandemics in human memory. It is estimated that more than 700 million people have been infected since it was discovered in Wuhan. China, late 2019. Thanks to global legislative policies and the widespread development and dissemination of anti-COVID-19 vaccines, the burden of the disease has been significantly reduced, with reports that vaccination efforts have saved more than 70% of patients. , survivors of the pandemic are suffering from symptoms such as: A previously unknown symptom – long corona.

Long coronavirus, also known as “post-COVID-19 syndrome,” “chronic COVID-19 syndrome,” and clinically “Post-COVID-19 acute sequelae (PASC),” has emerged as perhaps the worst legacy of the pandemic. I am. This now well-established but poorly understood condition is associated with COVID-19 and can persist for months or even years after the initial infection has resolved. It is characterized by the persistence or onset of symptoms. These symptoms include severe cognitive decline (brain fog), chronic fatigue, and multiorgan damage, resulting in significant economic and quality of life (QoL) losses for patients.

Alarmingly, 30% to 60% of all COVID-19 infections cause long-corona, and an estimated 350,000 Studies have shown that more than 10,000 people suffer from this condition. Unfortunately, even extensive global scientific efforts have not been able to elucidate the underlying mechanisms of long coronaviruses, hampering the development of diagnostic assays and clinical interventions for patients.

About research

In this study, researchers screened more than 1,000 prospective patients enrolled in Long COVID clinics in Belgium and Sweden to elucidate common mechanisms of Long COVID pathology and establish a highly sensitive and reliable model for this condition. We have developed a highly accurate diagnostic test. Only subjects with clinically confirmed mild or moderate COVID-19 infection were included. Severe cases were excluded because they overlapped with symptoms of post-intensive care syndrome.

Patients without objective measurements of disease-related organ damage (e.g., magnetic resonance imaging) [MRI]pulsatile arterial pressure measurement [EndoPAT]and postural orthostatic tachycardia syndrome [POTS]) have been excluded. Inclusion and exclusion criteria resulted in a final sample cohort of her 121 patients from Belgium (n = 31) and Sweden (n = 90).

The procedure included an enzyme-linked immunosorbent assay (ELISA) to detect and measure the patient's antibody response to SARS-CoV-2. These standard ELISAs were not observed to resolve differences in immunoglobulin A (IgA) and IgM, although differences between cases and convalescent controls in IgG titers were evident, and therefore A single molecule array (SIMOA) assay was employed. The SPEAR immunoassay was used to detect the presence of persistent SARS-CoV-2. spike protein Found in patient plasma samples.

These assays demonstrated antigenic responses in only about 10% of the study cohort, suggesting that they were unreliable and insensitive as diagnostic tools, leading the researchers to use the 51-parameter panel mass cytometry assay. were used to investigate possible immunological correlates. Additionally, Olinks assays were performed to measure the levels of cytokines and other plasma proteins in patients' plasma samples.

“autoantibodies Type I IFNs are associated with life-threatening COVID-19 pneumonia due to impaired IFN-I-mediated inhibition of viral replication. These autoantibodies increase in frequency with age, are more common in men than women for unknown reasons, and may explain up to 20% of deaths from COVID-19. The reason for the development of anti-cytokine autoantibodies is unknown in most cases, but most, if not all, patients have an inborn central tolerance defect due to AIRE deficiency in cis (APECED or APS1) or trans (alternative NF mutations). I am suffering from a disease. -kB pathway) all possess these autoantibodies and are highly susceptible to severe SARSCoV-2 infection. ”

To investigate the above, single-cell T-cell receptor (TCR) and message RNA (mRNA) sequencing of peripheral blood mononuclear cells (PBMCs) was performed. We then used GLIPH methodology to cluster memory CD8 T cell TCR sequences.

research result

In this study, while IgG responded to the SARS-CoV-2 spike (receptor binding domain); [RDB]Proteins measured by the SIMAO assay can be used as sensitive Long COVID markers, but IgA and IgM cannot be used as they are detected in approximately 10% of affected patients.This is because memory CD8 is⁺ T cells are suppressed and their clonal expansion is restricted by SARS-CoV-2, contradicting the previously hypothesized pathogenesis of an exhausted phenotype.

Strong and tenacious long COVID symptoms Despite high IgG concentrations, it has been suggested that there are differences between the initial and long-term adaptive responses of patient immunity to SARS-CoV-2.

“A strong initial adaptive response may increase the likelihood of viral clearance and reduce the risk of long-term COVID-19 infection, but once a viral reservoir is established, SARSCoV with increasing titers A sustained and elevated long-term response to -2 occurs, leading to chronic antigen stimulation.”

The results highlight that in cases of long-term COVID-19 infection, elevated serology is inversely correlated with CD8 expansion.⁺ T cell population. Elucidating the role of suppressed antiviral T cell responses as a key component of Long COVID pathology. Current and future research aimed at understanding the genetic basis of this revelation may enable the development of clinical therapies that can treat this hitherto incurable disease.

conclusion

In this study, we combined ELISA, SIMOA, and sequencing assays to investigate the association between circulating immunoglobulin titers and Long COVID pathology, elucidate the mechanism of action of Long COVID, and discover a universal Long COVID diagnostic test. achieved the dual purpose of advancing the Their findings revealed that, contrary to expectations, IgG titers in Long COVID patients increased after initial infection recovery, suggesting chronic antigen stimulation.

In contrast, IgA and IgM titers are very low and detectable in only 10% of cases, making them less reliable for Long COVID diagnosis.

*Important Notices: medRxiv has published preliminary scientific reports that have not been peer-reviewed and should therefore not be considered definitive, guide clinical practice or health-related behavior, or be treated as established information. Not.