Immunometabolic changes and potential biomarkers in CFS peripheral immune cells revealed by single-cell RNA sequencing

Abstract:

The pathogenesis of Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) remains unclear, though increasing evidence suggests inflammatory processes play key roles. In this study, single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) was used to decipher the immunometabolic profile in 4 ME/CFS patients and 4 heathy controls.

We analyzed changes in the composition of major PBMC subpopulations and observed an increased frequency of total T cells and a significant reduction in NKs, monocytes, cDCs and pDCs. Further investigation revealed even more complex changes in the proportions of cell subpopulations within each subpopulation. Gene expression patterns revealed upregulated transcription factors related to immune regulation, as well as genes associated with viral infections and neurodegenerative diseases.

CD4+ and CD8+ T cells in ME/CFS patients show different differentiation states and altered trajectories, indicating a possible suppression of differentiation. Memory B cells in ME/CFS patients are found early in the pseudotime, indicating a unique subtype specific to ME/CFS, with increased differentiation to plasma cells suggesting B cell overactivity. NK cells in ME/CFS patients exhibit reduced cytotoxicity and impaired responses, with reduced expression of perforin and CD107a upon stimulation. Pseudotime analysis showed abnormal development of adaptive immune cells and an enhanced cell-cell communication network converging on monocytes in particular.

Our analysis also identified the estrogen-related receptor alpha (ESRRA)-APP-CD74 signaling pathway as a potential biomarker for ME/CFS in peripheral blood. In addition, data from the GSE214284 database confirmed higher ESRRA expression in the monocyte cell types of male ME/CFS patients. These results suggest a link between immune and neurological symptoms.

The results support a disease model of immune dysfunction ranging from autoimmunity to immunodeficiency and point to amyloidotic neurodegenerative signaling pathways in the pathogenesis of ME/CFS. While the study provides important insights, limitations include the modest sample size and the evaluation of peripheral blood only.

These findings highlight potential targets for diagnostic biomarkers and therapeutic interventions. Further research is needed to validate these biomarkers and explore their clinical applications in managing ME/CFS.

Source: Sun Y, Zhang Z, Qiao Q, Zou Y, Wang L, Wang T, Lou B, Li G, Xu M, Wang Y, Zhang Z, Hou X, Chen L, Zhao R. Immunometabolic changes and potential biomarkers in CFS peripheral immune cells revealed by single-cell RNA sequencing. J Transl Med. 2024 Oct 11;22(1):925. doi: 10.1186/s12967-024-05710-w. PMID: 39394558. https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-024-05710-w (Full text)

Impact of inflammatory response in the acute phase of COVID-19 on predicting objective and subjective post-COVID fatigue

Abstract:

The biological predictors of objective and subjective fatigue in individuals with post-COVID syndrome remains unclear. This study aims to ascertain the predictive significance of the immune response measured during the acute phase of SARS-CoV-2 infection on various dimensions of fatigue 6–9 months post-infection.

We examined the association between immune markers obtained from the serum of 54 patients (mean age: 58.69 ± 10.90; female: 31%) and objective and subjective chronic fatigue using general linear mixed models. Level of IL-1RA, IFNγ and TNFα in plasma and the percentage of monocytes measured in the acute phase of COVID-19 predicted physical and total fatigue.

Moreover, the higher the concentration of TNFα (r=-0.40 ; p = .019) in the acute phase, the greater the lack of awareness of cognitive fatigue 6–9 months post-infection. These findings shed light on the relationship between acute inflammatory response and the persistence of both objective and subjective fatigue.

Source: Julie Péron, Anthony Nuber-Champier, Gautier Breville et al. Impact of inflammatory response in the acute phase of COVID-19 on predicting objective and subjective post-COVID fatigue, 28 May 2024, PREPRINT (Version 1) available at Research Square [https://doi.org/10.21203/rs.3.rs-4374986/v1] https://www.researchsquare.com/article/rs-4374986/v1 (Full text)

Persistence of circulating CD169+monocytes and HLA-DR downregulation underline the immune response impairment in PASC individuals: the potential contribution of different COVID-19 pandemic waves

Abstract:

The use of CD169 as a marker of viral infection has been widely discussed in the context of COVID-19, and in particular, its crucial role in the early detection of SARS-CoV-2 infection and its association with the severity and clinical outcome of COVID-19 were demonstrated. COVID-19 patients show relevant systemic alteration and immunological dysfunction that persists in individuals with post-acute sequelae of SARS-CoV-2 infection (PASC).

It is critical to implement the characterization of the disease, focusing also on the possible impact of the different COVID-19 waves and the consequent effects found after infection. On this basis, we evaluated by flow cytometry the expression of CD169 and HLA-DR on monocytes from COVID-19 patients and PASC individuals to better elucidate their involvement in immunological dysfunction, also evaluating the possible impact of different pandemic waves.

The results confirm CD169 RMFI is a good marker of viral infection. Moreover, COVID-19 patients and PASC individuals showed high percentage of CD169+ monocytes, but low percentage of HLA-DR+ monocytes and the alteration of systemic inflammatory indices. We have also observed alterations of CD169 and HLA-DR expression and indices of inflammation upon different COVID-19 waves.

The persistence of specific myeloid subpopulations suggests a role of CD169+ monocytes and HLA-DR in COVID-19 disease and chronic post-infection inflammation, opening new opportunities to evaluate the impact of specific pandemic waves on the immune response impairment and systemic alterations with the perspective to provide new tools to monitoring new variants and diseases associated to emerging respiratory viruses.

Source: Fanelli M, Petrone V, Maracchioni C, Chirico R, Cipriani C, Coppola L, Malagnino V, Teti E, Sorace C, Zordan M, Vitale P, Iannetta M, Balestrieri E, Rasi G, Grelli S, Malergue F, Sarmati L, Minutolo A, Matteucci C. Persistence of circulating CD169+monocytes and HLA-DR downregulation underline the immune response impairment in PASC individuals: the potential contribution of different COVID-19 pandemic waves. Curr Res Microb Sci. 2023 Dec 12;6:100215. doi: 10.1016/j.crmicr.2023.100215. PMID: 38187999; PMCID: PMC10767315. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10767315/ (Full text)

Clinical and pulmonary function analysis in long-COVID revealed that long-term pulmonary dysfunction is associated with vascular inflammation pathways and metabolic syndrome

Abstract:

Introduction: Long-term pulmonary dysfunction (L-TPD) is one of the most critical manifestations of long-COVID. This lung affection has been associated with disease severity during the acute phase and the presence of previous comorbidities, however, the clinical manifestations, the concomitant consequences and the molecular pathways supporting this clinical condition remain unknown. The aim of this study was to identify and characterize L-TPD in patients with long-COVID and elucidate the main pathways and long-term consequences attributed to this condition by analyzing clinical parameters and functional tests supported by machine learning and serum proteome profiling.

Methods: Patients with L-TPD were classified according to the results of their computer-tomography (CT) scan and diffusing capacity of the lungs for carbon monoxide adjusted for hemoglobin (DLCOc) tests at 4 and 12-months post-infection.

Results: Regarding the acute phase, our data showed that L-TPD was favored in elderly patients with hypertension or insulin resistance, supported by pathways associated with vascular inflammation and chemotaxis of phagocytes, according to computer proteomics. Then, at 4-months post-infection, clinical and functional tests revealed that L-TPD patients exhibited a restrictive lung condition, impaired aerobic capacity and reduced muscular strength. At this time point, high circulating levels of platelets and CXCL9, and an inhibited FCgamma-receptor-mediated-phagocytosis due to reduced FcγRIII (CD16) expression in CD14+ monocytes was observed in patients with L-TPD. Finally, 1-year post infection, patients with L-TPD worsened metabolic syndrome and augmented body mass index in comparison with other patient groups.

Discussion: Overall, our data demonstrated that CT scan and DLCOc identified patients with L-TPD after COVID-19. This condition was associated with vascular inflammation and impair phagocytosis of virus-antibody immune complexes by reduced FcγRIII expression. In addition, we conclude that COVID-19 survivors required a personalized follow-up and adequate intervention to reduce long-term sequelae and the appearance of further metabolic diseases.

Source: Sanhueza S, Vidal MA, Hernandez MA, Henriquez-Beltran ME, Cabrera C, Quiroga R, Antilef BE, Aguilar KP, Castillo DA, Llerena FJ, Fraga Figueroa M, Nazal M, Castro E, Lagos P, Moreno A, Lastra JJ, Gajardo J, Garcés P, Riffo B, Buchert J, Sanhueza R, Ormazába V, Saldivia P, Vargas C, Nourdin G, Koch E, Zuñiga FA, Lamperti L, Bustos P, Guzmán-Gutiérrez E, Tapia CA, Ferrada L, Cerda G, Woehlbier U, Riquelme E, Yuseff MI, Muñoz Ramirez BA, Lombardi G, De Gonzalo-Calvo D, Salomon C, Verdugo RA, Quiñones LA, Colombo A, Barría MI, Labarca G, Nova-Lamperti E. Clinical and pulmonary function analysis in long-COVID revealed that long-term pulmonary dysfunction is associated with vascular inflammation pathways and metabolic syndrome. Front Med (Lausanne). 2023 Oct 6;10:1271863. doi: 10.3389/fmed.2023.1271863. PMID: 37869162; PMCID: PMC10590130. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10590130/ (Full text)

Monocytes subpopulations pattern in the acute respiratory syndrome coronavirus 2 virus infection and after long COVID-19

Abstract:

Introduction and objective: The present study sought to characterize the pattern of monocyte subpopulations in patients during the course of the infections caused by SARS-CoV-2 virus or who presented long COVID-19 syndrome compared to monocytes from patients with zika virus (Zika) or chikungunya virus (CHIKV).

Casuistry: Study with 89 peripheral blood samples from patients, who underwent hemogram and serology (IgG and IgM) for detection of Zika (Control Group 1, n = 18) or CHIKV (Control Group 2, n = 9), and from patients who underwent hemogram and reverse transcription polymerase chain reaction for detection of SARS-CoV-2 at the acute phase of the disease (Group 3, n = 19); and of patients who presented long COVID-19 syndrome (Group 4, n = 43). The monocyte and subpopulations counts were performed by flow cytometry.

Results: No significant difference was observed in the total number of monocytes between the groups. The classical (CD14++CD16) and intermediate (CD14+CD16+) monocytes counts were increased in patients with acute infection or with long COVID-19 syndrome. The monocytes subpopulations counts were lower in patients with infection Zika or CHIKV.

Conclusion: Increase in the monocyte subpopulations in patients with acute infection or with long COVID-19 syndrome may be an important finding of differentiated from the infection Zika or CHIKV.

Source: Pereira VIC, de Brito Junior LC, Falcão LFM, da Costa Vasconcelos PF, Quaresma JAS, Berg AVVD, Paixão APS, Ferreira RIS, Diks IBC. Monocytes subpopulations pattern in the acute respiratory syndrome coronavirus 2 virus infection and after long COVID-19. Int Immunopharmacol. 2023 Oct 5;124(Pt B):110994. doi: 10.1016/j.intimp.2023.110994. Epub ahead of print. PMID: 37804653. https://www.sciencedirect.com/science/article/abs/pii/S156757692301319X

Immunological profiling in long COVID: overall low grade inflammation and T-lymphocyte senescence and increased monocyte activation correlating with increasing fatigue severity

Abstract:

Background: Many patients with SARS-CoV-2 infection develop long COVID with fatigue as one of the most disabling symptoms. We performed clinical and immune profiling of fatigued and non-fatigued long COVID patients and age- and sex-matched healthy controls (HCs).

Methods: Long COVID symptoms were assessed using patient-reported outcome measures, including the fatigue assessment scale (FAS, scores ≥22 denote fatigue), and followed up to one year after hospital discharge. We assessed inflammation-related genes in circulating monocytes, serum levels of inflammation-regulating cytokines, and leukocyte and lymphocyte subsets, including major monocyte subsets and senescent T-lymphocytes, at 3-6 months post-discharge.

Results: We included 37 fatigued and 36 non-fatigued long COVID patients and 42 HCs. Fatigued long COVID patients represented a more severe clinical profile than non-fatigued patients, with many concurrent symptoms (median 9 [IQR 5.0-10.0] vs 3 [1.0-5.0] symptoms, p<0.001), and signs of cognitive failure (41%) and depression (>24%). Immune abnormalities that were found in the entire group of long COVID patients were low grade inflammation (increased inflammatory gene expression in monocytes, increased serum pro-inflammatory cytokines) and signs of T-lymphocyte senescence (increased exhausted CD8+ TEMRA-lymphocytes). Immune profiles did not significantly differ between fatigued and non-fatigued long COVID groups. However, the severity of fatigue (total FAS score) significantly correlated with increases of intermediate and non-classical monocytes, upregulated gene levels of CCL2, CCL7, and SERPINB2 in monocytes, increases in serum Galectin-9, and higher CD8+ T-lymphocyte counts.

Conclusion: Long COVID with fatigue is associated with many concurrent and persistent symptoms lasting up to one year after hospitalization. Increased fatigue severity associated with stronger signs of monocyte activation in long COVID patients and potentially point in the direction of monocyte-endothelial interaction. These abnormalities were present against a background of immune abnormalities common to the entire group of long COVID patients.

Source: Berentschot Julia C., Drexhage Hemmo A., Aynekulu Mersha Daniel G., Wijkhuijs Annemarie J. M., GeurtsvanKessel Corine H., Koopmans Marion P. G., Voermans Jolanda J. C., Hendriks Rudi W., Nagtzaam Nicole M. A., de Bie Maaike, Heijenbrok-Kal Majanka H., Bek L. Martine, Ribbers Gerard M., van den Berg-Emons Rita J. G., Aerts Joachim G. J. V., Dik Willem A., Hellemons Merel E. Immunological profiling in long COVID: overall low grade inflammation and T-lymphocyte senescence and increased monocyte activation correlating with increasing fatigue severity. Frontiers in Immunology, vol 14, 2023. DOI=10.3389/fimmu.2023.1254899 ISSN=1664-3224 https://www.frontiersin.org/articles/10.3389/fimmu.2023.1254899/full (Full text)

 

Long Covid: clues about causes

Abstract:(Full text

Many patients report persistent symptoms after resolution of acute COVID-19, regardless of SARS-CoV-2 variant and even if the initial illness is mild [1, 2]. A multitude of symptoms have been described under the umbrella term ‘Long COVID’, otherwise known as ‘post-COVID syndrome’ or ‘post-acute sequelae of SARS-CoV-2 (PASC)’; for simplicity we will use the term Long COVID.

Symptoms are diverse but include breathlessness, fatigue and brain fog, reported to affect up to 69% of cases [3]. Long COVID can be debilitating, 45.2% of patients requiring a reduced work schedule [4]. The WHO estimates that 17 million people in Europe have experienced Long COVID during the first two years of the pandemic [5]. SARS-CoV-2 variants continue to circulate and the risk of post-acute complications remains; a recent study of 56 003 UK patients found that even after Omicron infection, 4.5% suffered persistent symptoms [6].

It is therefore likely that Long COVID will provide a substantial medical and economic burden for the foreseeable future. There is an urgent need to understand mechanisms of disease and develop effective treatments based on this understanding.

Source: Liew F, Efstathiou C, Openshaw PJ. Long Covid: clues about causes. Eur Respir J. 2023 Mar 23:2300409. doi: 10.1183/13993003.00409-2023. Epub ahead of print. PMID: 36958743; PMCID: PMC10040855. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10040855/ (Full text)

Monocyte migration profiles define disease severity in acute COVID-19 and unique features of long COVID

Abstract:

Background: COVID-19 is associated with a dysregulated immune response but it is unclear how immune dysfunction contributes to the chronic morbidity persisting in many COVID-19 patients during convalescence (long COVID).

Methods: We assessed phenotypical and functional changes of monocytes in COVID-19 patients during hospitalization and up to 9 months of convalescence following COVID-19, respiratory syncytial virus (RSV) or influenza A (flu). Progressive fibrosing interstitial lung disease (PFILD) patients were included a positive control for severe, ongoing lung injury.

Results: Monocyte alterations in acute COVID-19 patients included aberrant expression of leucocyte migration molecules, continuing into convalescence (n=142) and corresponding to specific symptoms of long COVID. Long COVID patients with unresolved lung injury, indicated by sustained shortness of breath and abnormal chest radiology, were defined by high monocyte expression of chemokine receptor CXCR6 (p<0.0001) and adhesion molecule PSGL-1 (p<0.01), alongside preferential migration of monocytes towards CXCR6 ligand CXCL16 (p<0.05) which is abundantly expressed in the lung. Monocyte CXCR6 and lung CXCL16 were heightened in PFILD patients (p<0.001) confirming a role for the CXCR6-CXCL16 axis in ongoing lung injury. Conversely, monocytes from long COVID patients with ongoing fatigue exhibited sustained reduction of the prostaglandin-generating enzyme COX-2 (p<0.01) and CXCR2 expression (p<0.05). These monocyte changes were not present in RSV or flu convalescence.

Conclusions: Our data define unique monocyte signatures that define subgroups of long COVID patients, indicating a key role for monocyte migration in COVID-19 pathophysiology. Targeting these pathways may provide novel therapeutic opportunities in COVID-19 patients with persistent morbidity.

Source: Scott NA, Pearmain L, Knight SB, Brand O, Morgan DJ, Jagger C, Harbach S, Khan S, Shuwa HA, Franklin M, Kästele V, Williams T, Prise I, McClure FA, Hackney P, Smith L, Menon M, Konkel JE, Lawless C, Wilson J, Mathioudakis AG, Stanel SC, Ustianowski A, Lindergard G, Brij S, Diar Bakerly N, Dark P, Brightling C, Rivera-Ortega P, Lord GM, Horsley A; CIRCO; Piper Hanley K, Felton T, Simpson A, Grainger JR, Hussell T, Mann ER. Monocyte migration profiles define disease severity in acute COVID-19 and unique features of long COVID. Eur Respir J. 2023 Mar 15:2202226. doi: 10.1183/13993003.02226-2022. Epub ahead of print. PMID: 36922030. https://erj.ersjournals.com/content/early/2023/02/23/13993003.02226-2022 (Full article available as PDF file)

Transcriptional reprogramming from innate immune functions to a pro-thrombotic signature by monocytes in COVID-19

Abstract:

Although alterations in myeloid cells have been observed in COVID-19, the specific underlying mechanisms are not completely understood. Here, we examine the function of classical CD14+ monocytes in patients with mild and moderate COVID-19 during the acute phase of infection and in healthy individuals.

Monocytes from COVID-19 patients display altered expression of cell surface receptors and a dysfunctional metabolic profile that distinguish them from healthy monocytes. Secondary pathogen sensing ex vivo leads to defects in pro-inflammatory cytokine and type-I IFN production in moderate COVID-19 cases, together with defects in glycolysis.

COVID-19 monocytes switch their gene expression profile from canonical innate immune to pro-thrombotic signatures and are functionally pro-thrombotic, both at baseline and following ex vivo stimulation with SARS-CoV-2. Transcriptionally, COVID-19 monocytes are characterized by enrichment of pathways involved in hemostasis, immunothrombosis, platelet aggregation and other accessory pathways to platelet activation and clot formation. These results identify a potential mechanism by which monocyte dysfunction may contribute to COVID-19 pathology.

Source: Maher AK, Burnham KL, Jones EM, Tan MMH, Saputil RC, Baillon L, Selck C, Giang N, Argüello R, Pillay C, Thorley E, Short CE, Quinlan R, Barclay WS, Cooper N, Taylor GP, Davenport EE, Dominguez-Villar M. Transcriptional reprogramming from innate immune functions to a pro-thrombotic signature by monocytes in COVID-19. Nat Commun. 2022 Dec 26;13(1):7947. doi: 10.1038/s41467-022-35638-y. PMID: 36572683; PMCID: PMC9791976. https://www.nature.com/articles/s41467-022-35638-y (Full text)

Clinical and laboratory predictors of long-COVID in children: a single center retrospective study

Abstract:

Objective: The majority of children experience a mild course of acute Coronavirus Disease 2019 (COVID-19). Only few studies have looked at long-term recovery from COVID-19 infection in children. The purpose of this study was to identify the predictors of long-COVID by performing a thorough analysis of the clinical, laboratory, and demographic characteristics of children with COVID-19.

Patients and methods: Between August and October 2021, data were obtained retrospectively from the medical records of 251 children diagnosed with COVID-19 at a tertiary single-center hospital. The prognostic effects of admission-related factors were compared between patients who experienced long-lasting symptoms and those who did not.

Results: Long-COVID symptoms were noted in 12.4% of patients. Joint pain (7.6%), lumbago (4.8%), and headache (3.2%) were the most common symptoms. The mean onset of long-COVID symptoms was 1.35±0.49 months. The onset of long-COVID symptoms was 4 weeks after initial diagnosis in 64.5% of patients and 4-8 weeks later in 35.5% of the patients. The mean duration of long-COVID symptoms was 5.32±2.51 months. Children with long-COVID had higher leukocytes, neutrophils, monocytes, basophils, platelets, and D-dimer when compared with patients without long-COVID (p < 0.001). Leukocytes, neutrophils, monocytes, platelets, and D-dimer had the highest AUC in the ROC analysis (0.694, 0.658, 0.681, 0.667, and 0.612, respectively) and were statistically significant.

Conclusions: Despite the majority of children with COVID-19 having mild or asymptomatic acute disease, the majority of long-COVID symptoms were associated with functional impairment between 1 and 9 months after the start of the infection. Increased leukocytes, monocytes, neutrophils, platelets, and D-dimer appear to be the most powerful laboratory predictors for long-COVID and monitoring these predictors may assist clinicians to identify and follow-up patients with higher risk for long-COVID.

Source: Güven D, Buluş AD. Clinical and laboratory predictors of long-COVID in children: a single center retrospective study. Eur Rev Med Pharmacol Sci. 2022 Oct;26(20):7695-7704. doi: 10.26355/eurrev_202210_30046. PMID: 36314341.  https://www.europeanreview.org/article/30046 (Full text)