Cytokine profiles associated with persisting symptoms of post-acute sequelae of COVID-19

Abstract:

Background/aims: Post-acute sequelae of COVID-19 (PASC) are highly heterogeneous; therefore, the pathophysiological mechanisms for PASC remain unclear. In this study, we aimed to examine the immunologic aspects of various PASC symptoms.

Methods: We prospectively enrolled adults aged ≥ 18 years who were diagnosed with COVID-19 between August 2022 and September 2023. Blood samples were collected from all participants, who were interviewed using a questionnaire for PASC symptoms at least once between 1 and 6 months after the COVID-19 diagnosis. For immunological evaluation, plasma concentrations of SARS-CoV-2 spike subunit 1-specific IgG and 33 cytokines were measured using enzyme-linked immunosorbent assays and multiplex-based immunoassay, respectively.

Results: In total, 156 pairs of blood samples and symptom reports from 79 participants were eligible for analysis. The most frequent symptom was fatigue, followed by post exertional malaise, chronic cough, thirst, and brain fog. Gastrointestinal symptoms, chest pain, post exertional malaise, smell/taste change, fatigue, brain fog, abnormal movement, and palpitation were accompanied by significant increases in IL-10, VEGF, and inflammatory cytokines like MIP-1α, IL-1β, IL-6, IL-8, MIG, granzyme A, and CX3CL1 levels, while chronic cough, dizziness, dyspnea, and hair loss were not accompanied by significant differences in cytokine levels.

Conclusion: Symptoms classified into different categories based on the dysfunctional organs may share a common pathophysiology regarding elevation of certain cytokines. Although PASC symptoms are heterogeneous, our findings suggest that T-cell recruitment, thrombosis, and increased vascular permeability might contribute to various symptom clusters sharing common pathophysiological mechanisms.

Source: Kwon JS, Chang E, Jang HM, Kim JY, Kim W, Son JY, Cha J, Jang CY, Bae S, Jung J, Kim MJ, Chong YP, Lee SO, Choi SH, Kim YS, Kim SH. Cytokine profiles associated with persisting symptoms of post-acute sequelae of COVID-19. Korean J Intern Med. 2025 Jul;40(4):667-675. doi: 10.3904/kjim.2024.217. Epub 2025 Jul 1. PMID: 40635493. https://kjim.org/journal/view.php?doi=10.3904/kjim.2024.217 (Full text)

Assessing the influence of lived-experience experts on healthcare providers in a virtual community of practice: a qualitative study

Abstract:

Long COVID, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and other poorly understood post-acute infection syndromes (PAIS) can present with unexplained symptoms or conditions that may be misunderstood by healthcare providers, causing delays in diagnosis and care. To address these issues, the Centers for Disease Control and Prevention (CDC) funded the Long COVID and Fatiguing Illness Recovery Program (LC&FIRP), initiated as a pilot project to assess whether providing tele-mentoring and other online education for primary care providers could help them improve the quality of life and support the recovery of their patients with these conditions.

The LC&FIRP multi-disciplinary team-based care approach is built on the Extension for Community Healthcare Outcomes (ECHO) learning model, which is an evidence-based virtual learning framework developed by the University of New Mexico and designed to disseminate and implement best practices, especially in under-resourced areas. A distinctive feature of LC&FIRP was the inclusion of lived-experience experts. To explore the influence of lived-experience experts on the care patients received, we collected the educational recommendations provided by the lived-experience experts during webinar sessions (January 2022-March 2024) and grouped these by themes.

The major themes that emerged included validation of patients’ illness experience; attitudes and beliefs about Long COVID, ME/CFS, and PAIS; understanding patients’ challenges and communicating with empathy; navigating referrals; recognizing and supporting disability; and supporting self-care. Investigators also interviewed patients of the Family Health Centers of San Diego (FHCSD) about their experiences receiving care from participating primary care providers and employed content analysis methods to code interview transcripts to identify themes among patients’ perspectives. Positive comments from the patients about topics emphasized by the lived-experience experts provided evidence of providers’ uptake and application of the experts’ recommendations and support the value of involving lived-experience experts in medical education to improve health services.

Source: Weaver SS, Carry M, Bertolli J, Godino J, Struminger B, Taren D, Scott JD, Sharp SP, Samaniego J, Bean DR, Issa A, Lin JS, Unger ER, Ramers CB. Assessing the influence of lived-experience experts on healthcare providers in a virtual community of practice: a qualitative study. Front Health Serv. 2025 Jun 27;5:1562651. doi: 10.3389/frhs.2025.1562651. PMID: 40656206; PMCID: PMC12245761. https://pmc.ncbi.nlm.nih.gov/articles/PMC12245761/ (Full text)

Prevalence and severity of neurologic symptoms in Long-COVID and the role of pre-existing conditions, hospitalization, and mental health

Abstract:

Background: Long-COVID refers to ongoing, relapsing, or new symptoms present 30 or more days after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. This study examined the prevalence and severity of neurologic symptoms at greater than 1 month following acute SARS-CoV-2 infection and the influence of pre-existing neurologic and psychiatric conditions, current depression and anxiety status, and hospitalization on the presence and severity of these symptoms.

Methods: This prospective cohort study recruited primarily self-referred Long-COVID participants with confirmed SARS-CoV-2 infection. Online questionnaires inquiring about pre-existing conditions, neurologic symptoms and their severity pre, during and post COVID-19, and current anxiety and depression screening were completed by 213 participants at a median time of 8 months after infection. Descriptive analyses and prevalence modeling were performed.

Results: The most frequent neurologic symptoms post COVID-19 were fatigue, concentration/memory difficulties, unrefreshed sleep, and dysarthria/word finding difficulties (73.2–86.4%). Neurologic symptoms were highly prevalent with significantly greater odds post COVID-19 compared to pre for all symptoms and higher prevalence at time periods farther from infection, including those implicit in fibromyalgia and myalgic encephalomyelitis/chronic fatigue syndrome. Several severe neurologic symptoms were significantly more prevalent post COVID-19. Moderate to severe anxiety (34%) and depression (27%) were observed post COVID-19. Preexisting neurologic or psychiatric conditions did not demonstrate any significant difference in neurologic symptom prevalence post COVID-19. Those who met criteria for moderate or severe anxiety post COVID-19 had a significant difference in prevalence of fatigue, sensitivity to touch and unrefreshed sleep. Similarly, fatigue, concentration/memory difficulty and unrefreshed sleep were more prevalent in moderate to severe depression. There were no significant differences in neurologic symptom prevalence in a hospitalized group when compared to non- hospitalized.

Conclusion: Long-COVID has a high burden of long lasting and severe neurological sequelae. These sequelae are independent of pre-existing self-reported neurologic and psychiatric conditions, as well as previous hospitalization. Current moderate to severe anxiety and depression status can impact fatigue, cognition, and sleep post COVID-19. Focus on the biological impact of SARS-CoV-2 on the nervous system will be essential in ameliorating the tremendous symptom burden left in the wake of the COVID-19 pandemic.

Source: Huff Hanalise V. , Roberts Henry , Bartrum Elizabeth , Norato Gina , Grayson Nicholas , Fleig Katherine , Wilkerson Miciah J. , Stussman Barbara J. , Nath Avindra , Walitt Brian. Prevalence and severity of neurologic symptoms in Long-COVID and the role of pre-existing conditions, hospitalization, and mental health. Frontiers in Neurology, Volume 16 – 2025 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1562084 10.3389/fneur.2025.1562084 ISSN:1664-2295 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1562084/full (Full text)

Two Neurocognitive Domains Identified for Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-Acute Sequelae of COVID-19

Abstract:

Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Post-Acute Sequelae of COVID-19 (PASC) often have neurocognitive complaints that involve memory and concentration problems and difficulties paying attention. Other neurocognitive domains such as hypersensitivity to noise and light have rarely been included as aspects of neurocognitive impairment for these post-viral conditions.

The current study evaluated a more extensive list of neurocognitive items for a group of 2,313 patients with ME/CFS and 299 patients with PASC. Exploratory factor analyses found two factors for each patient group, one involving classic memory and concentration symptoms and the other involving sensory overload phenomena. The findings suggest that researchers might consider expanding the types of self-report neurocognitive symptoms among patients with these post-viral illnesses.

Source: Ariadna E Sandoval, Mingqi Li, Leonard A. Jason. Two Neurocognitive Domains Identified for Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-Acute Sequelae of COVID-19. Front. Neurol., Sec. Cognitive and Behavioral Neurology, Volume 16 – 2025 | doi: 10.3389/fneur.2025.1612548 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1612548/abstract

Immune Signatures in Post-Acute Sequelae of COVID-19 (PASC) and Myalgia/Chronic Fatigue Syndrome (ME/CFS): Insights from the Fecal Microbiome and Serum Cytokine Profiles

Abstract:

While there are many postulates for the etiology of post-viral chronic fatigue and other symptomatology, little is known. We draw on our past experience of these syndromes to devise means which can expose the primary players of this malady in terms of a panoply participating biomolecules and the state of the stool microbiome.
Using databases established from a large dataset of patients at risk of colorectal cancer who were followed longitudinally over 3 decades, and a smaller database dedicated to building a Long PASC cohort (Post-Acute Sequelae of COVID-19), we were able to ascertain factors that predisposed patients to (and resulted in) significant changes in various biomarkers, i.e., the stool microbiome and serum cytokine levels, which we verified by collecting stool and serum samples.
There were significant changes in the stool microbiome with an inversion from the usual Bacillota and Bacteroidota species. Serum cytokines showed significant differences in MIP-1β versus TARC (CC chemokine ligand 17) in patients with either PASC or COVID-19 (p < 0.02); IL10 versus IL-12p70a (p < 0.02); IL-1b versus IL-6 (p < 0.01); MCP1 versus TARC (p < 0.03); IL-8 versus TARC (p < 0.002); and Eotaxin3 versus TARC (p < 0.004) in PASC. Some changes were seen solely in COVID-19, including MDC versus MIP-1α (p < 0.01); TNF-α versus IL-1-β (p < 0.06); MCP4 versus TARC (p < 0.0001). We also show correlates with chronic fatigue where an etiology was not identified.
These findings in patients with positive criteria for PASC show profound changes in the microbiome and serum cytokine expression. Patients with chronic fatigue without clear viral etiologies also have common associations, including a history of tonsillectomy, which evokes a likely immune etiology.
Source: Tobi, M., Chaudhari, D., Ryan, E. P., Rossi, N. F., Koka, O., Baxter, B., Tipton, M., Dutt, T. S., Tobi, Y., McVicker, B., & Angoa-Perez, M. (2025). Immune Signatures in Post-Acute Sequelae of COVID-19 (PASC) and Myalgia/Chronic Fatigue Syndrome (ME/CFS): Insights from the Fecal Microbiome and Serum Cytokine Profiles. Biomolecules15(7), 928. https://doi.org/10.3390/biom15070928 https://www.mdpi.com/2218-273X/15/7/928 (Full text)

Advancing research on regulatory autoantibodies targeting GPCRs: Insights from the 5th international symposium

Abstract:

The 5th International Symposium on Regulatory Autoantibodies Targeting GPCR (RAB-GPCRs) advanced the understanding of the significant role played by autoantibodies targeting G-protein-coupled receptors (GPCRs) in various human diseases. Once considered passive markers, RAB-GPCRs are now recognized as active modulators of cellular signaling, immune regulation, and inflammation.

The symposium highlighted their involvement in multiple prominent pathologies, including autoimmune diseases, cardio- and cerebrovascular diseases, and neuroimmunologic disorders such as myalgic encephalomyelitis/chronic fatigue syndrome and post-COVID-19 syndrome (ME/CFS/PCS), as well as solid organ and hematopoietic stem cell transplantation (SOT/HSCT). Experts from rheumatology, immunology, and neurology presented interdisciplinary discussions on the potential of RAB-GPCRs as biomarkers and therapeutic targets. Advances in screening methods, biomarker identification, and therapeutic strategies were shared, emphasizing their diagnostic potential and application in novel therapeutic interventions.

This report summarizes key insights from the symposium, particularly focusing on the modulatory properties of RAB-GPCRs and their relevance in both immune-mediated diseases and other pathologies (e.g., vascular, degenerative) that are traditionally not considered primarily immune-mediated. Ongoing research is expected to further establish these autoantibodies as crucial components in disease modulation and systems biology contexts, offering new opportunities for precision medicine and improved clinical outcomes in immune-related disorders.

Source: Cabral-Marques O, Schimke LF, Moll G, Filgueiras IS, Nóbile AL, Adri AS, do Vale FYN, Usuda JN, Corrêa YLG, Albuquerque D, Nava RG, Santos RS, Dias HD, Silva HF, Marconi PB, Catar R, Adu-Gyamfi M, Wang P, Khan TA, Hackel AM, Leheis A, Stähle A, Müller A, Schmidt C, Radunovic C, Adjailia EB, Grasshoff H, Humrich JY, Menz J, Fourlakis K, Winziers M, Jäpel M, Wegner MV, Lamprecht P, Nieberding R, Akbarzadeh R, Arnold S, Jendrek S, Klapa S, Augustin S, Biedermann S, Schinke S, Scheerer P, Endres M, Schulze-Forster K, Paul F, Yu X, Sotzny F, Sakmar TP, Banasik M, Haghikia A, Hoffmann MH, Veprintsev D, Witte T, Dalmolin RJS, Ochs HD, Heidecke H, Scheibenbogen C, Shoenfeld Y, Riemekasten G. Advancing research on regulatory autoantibodies targeting GPCRs: Insights from the 5th international symposium. Autoimmun Rev. 2025 Jun 19:103855. doi: 10.1016/j.autrev.2025.103855. Epub ahead of print. PMID: 40543860. https://www.sciencedirect.com/science/article/pii/S1568997225001156 (Full text)

A Mechanical Basis: Brainstem Dysfunction as a Potential Etiology of ME/CFS and Long COVID

Abstract:
The underlying pathologies driving post-acute infectious syndromes (e.g. myalgic encephalomyelitis / chronic fatigue syndrome, long COVID, etc) remain poorly understood. Given the extreme burden these illnesses impose on suffers, and the dramatic increase in cases following the COVID-19 pandemic, it is important to establish a deeper understanding of these pathologies.
We propose a model of how ME/CFS (and related illnesses), might emerge following a viral insult. Central to this hypothesis is the recognition that the core diagnostic features of ME/CFS involve bodily systems known to be governed by the brainstem. This is consistent with the growing literature suggesting that spinal and craniocervical pathologies are over-represented in people with ME/CFS and other post-infectious disorders.
We hypothesize that a non-trivial number of cases of ME/CFS and Long Covid (LC) may have a “mechanical basis.” We propose that an infectious insult may trigger an initial loss of connective tissue integrity in susceptible individuals (e.g. those with pre-existing hypermobility spectrum disorders), which in turn leads to instability at the craniocervical junction, and ultimately mechanical deformation of the brainstem. This ultimately causes widespread autonomic nervous system and immune system dysfunction due to aberrant signaling from the deformed nuclei.
This causal chain may also lead to a vicious cycle: if the dysregulation produced by the initial brainstem deformation leads to a deranged immune response or state of chronic hyper-inflammation, further expression of connective tissue degrading and remodeling factors such as MMPs and mast cells may be triggered. This could further degrade the connective tissues of the craniocervical junction and, in turn, increase mechanical deformation of the brainstem, leading to symptom exacerbation over time and leading to the chronic, lifelong presentation typical of ME/CFS.
Source: Wood, J., Varley, T., Hartman, J., Melia, N., Kaufman, D., & Falor, T. (2025). A Mechanical Basis: Brainstem Dysfunction as a Potential Etiology of ME/CFS and Long COVID. Preprints. https://doi.org/10.20944/preprints202506.0874.v1 https://www.preprints.org/manuscript/202506.0874/v1 (Full text)

Core features and inherent diversity of post-acute infection syndromes

Abstract:

Post-acute infection syndromes (PAIS), i.e., long-lasting pathologies subsequent to infections that do not properly resolve, have both a common core and a broad diversity of manifestations. PAIS include a group of core symptoms (pathological fatigue, cognitive problems, sleep disorders and pain) accompanied by a large set of diverse symptoms. Core and diverse additional symptoms, which can persist for years, exhibiting periods of relapses and remissions, usually start suddenly after an apparently common infection.

PAIS display highly variable clinical features depending on the nature of the initial pathogen, and to an even larger extent, on the diversity of preexisting individual terrains in which PAIS are rooted. In a first part, I discuss biological issues related to the persistence of microbial antigens, dysregulated immune responses, reactivation of latent viruses, different potential self-sustained inflammatory loops, mitochondrial dysfunction, metabolic disorders in the tryptophan- kynurenin pathway (TKP) with impact on serotonin, and consequences of a dysfunctional bidirectional microbiota-gut-brain axis.

The second part deals with the nervous system dependence of PAIS. I rely on the concept of interoception, the process by which the brain senses, integrates and interprets signals originating from within the body, and sends feebacks aimed at maintaining homeostasis. Interoception is central for understanding the origin of fatigue, dysautonomia, dysfunctioning of the hypothalamus-pituitary-adrenal (HPA) axis, and its relation with stress, inflammation or depression.

I propose that all individual predispositions leading to self-sustained vicious circles constitute building blocks that can self-assemble in many possible ways, to give rise to both core and diverse features of PAIS. A useful discrimination between different PAIS subtypes should be obtained with a composite profiling including biomarkers, questionnaires and functional tests so as to take into account PAIS multidimensionality.

Source: Trautmann A. Core features and inherent diversity of post-acute infection syndromes. Front Immunol. 2025 Jun 3;16:1509131. doi: 10.3389/fimmu.2025.1509131. PMID: 40529374; PMCID: PMC12170329. https://pmc.ncbi.nlm.nih.gov/articles/PMC12170329/ (Full text)

Long-term neurological and cognitive impact of COVID-19: a systematic review and meta-analysis in over 4 million patients

Abstract:

Background: Neuropsychiatric symptoms emerged early in the COVID-19 pandemic as a key feature of the virus, with research confirming a range of neuropsychiatric manifestations linked to acute SARS-CoV-2 infection. However, the persistence of neurological symptoms in the post-acute and chronic phases remains unclear. This meta-analysis assesses the long-term neurological effects of COVID-19 in recovered patients, providing insights for mental health service planning.

Methods: A comprehensive literature search was conducted across five electronic databases: PubMed, Scopus, Web of Science, EBSCO, and CENTRAL, up to March 22, 2024. Studies evaluating the prevalence of long-term neurological symptoms in COVID-19 survivors with at least six months of follow-up were included. Pooled prevalence estimates, subgroup analyses, and meta-regression were performed, and publication bias was assessed.

Results: The prevalence rates for the different symptoms were as follows: fatigue 43.3% (95% CI [36.1-50.9%]), memory disorders 27.8% (95% CI [20.1-37.1%]), cognitive impairment 27.1% (95% CI [20.4-34.9%]), sleep disorders 24.4% (95% CI [18.1-32.1%]), concentration impairment 23.8% (95% CI [17.2-31.9%]), headache 20.3% (95% CI [15-26.9%]), dizziness 16% (95% CI [9.5-25.7%]), stress 15.9% (95% CI [10.2-24%]), depression 14.0% (95% CI [10.1-19.2%]), anxiety 13.2% (95% CI [9.6-17.9%]), and migraine 13% (95% CI [2.2-49.8%]). Significant heterogeneity was observed across all symptoms. Meta-regression analysis showed higher stress, fatigue, and headache in females, and increased stress and concentration impairment with higher BMI.

Conclusions: Neurological symptoms are common and persistent in COVID-19 survivors. This meta-analysis highlights the significant burden these symptoms place on individuals, emphasizing the need for well-resourced multidisciplinary healthcare services to support post-COVID recovery.

Source: Elboraay T, Ebada MA, Elsayed M, Aboeldahab HA, Salamah HM, Rageh O, Elmallahy M, AboElfarh HE, Mansour LS, Nabil Y, Eltawab AKA, Atwan H, Alkanj S. Long-term neurological and cognitive impact of COVID-19: a systematic review and meta-analysis in over 4 million patients. BMC Neurol. 2025 Jun 14;25(1):250. doi: 10.1186/s12883-025-04174-9. PMID: 40514644; PMCID: PMC12166599. https://pmc.ncbi.nlm.nih.gov/articles/PMC12166599/ (Full text)

Persistent immune dysregulation and metabolic alterations following SARS-CoV-2 infection

Abstract:

SARS-CoV-2 can cause a variety of post-acute sequelae including Long COVID19 (LC), a complex, multisystem disease characterized by a broad range of symptoms including fatigue, cognitive impairment, and post-exertional malaise. The pathogenesis of LC is incompletely understood.

In this study, we performed comprehensive cellular and transcriptional immunometabolic profiling within a cohort that included SARS-CoV-2-naïve controls (NC, N=30) and individuals with prior COVID-19 (~4-months) who fully recovered (RC, N=38) or went on to experience Long COVID symptoms (N=58).

Compared to the naïve controls, those with prior COVID-19 demonstrated profound metabolic and immune alterations at the proteomic, cellular, and epigenetic level. Specifically, there was an enrichment in immature monocytes with sustained inflammasome activation and oxidative stress, elevated arachidonic acid levels, decreased tryptophan, and variation in the frequency and phenotype of peripheral T-cells. Those with LC had increased CD8 T-cell senescence and a distinct transcriptional profile within CD4 and CD8 T-cells and monocytes by single cell RNA sequencing. Our findings support a profound and persistent immunometabolic dysfunction that follows SARS-CoV-2 which may form the pathophysiologic substrate for LC.

Our findings suggest that trials of therapeutics that help restore immune and metabolic homeostasis may be warranted to prevent, reduce, or resolve LC symptoms.

Source: Lage SL, Bricker-Holt K, Rocco JM, Rupert A, Donovan FX, Abramzon YA, Chandrasekharappa SC, McNinch C, Cook L, Amaral EP, Rosenfeld G, Dalhuisen T, Eun A, Hoh R, Fehrman E, Martin JN, Deeks SG, Henrich TJ, Peluso MJ, Sereti I. Persistent immune dysregulation and metabolic alterations following SARS-CoV-2 infection. medRxiv [Preprint]. 2025 Apr 17:2025.04.16.25325949. doi: 10.1101/2025.04.16.25325949. PMID: 40321289; PMCID: PMC12047922. https://pmc.ncbi.nlm.nih.gov/articles/PMC12047922/ (Full text)