Convalescent Patients Research Articles

Hemostatic imbalance underlying preterm delivery in COVID-19 convalescent patients

Aim: to study the role of the hemostatic system in pretem delivery in pregnant women who have had COVID-19 in the gestation period from 14 to 16 weeks.Materials and Methods. A prospective single-center observational study was conducted by enrolling 63 pregnant women with verified COVID-19 at 14–16 weeks of gestation. The main group consisted of 37 patients with preterm birth (PB), comparison group – 26 patients labour activity that occurred at least at gestational age of 37 weeks. Clinical and anamnestic data and dynamic changes in fibrinogen and D-dimer level, activity of tissue factor (TF), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) were analyzed; thrombin generation assay (TGA) was performed.Results. It was found that severity of COVID-19 infection did not determine the timing of delivery that depended on patient comorbid condition. All PB observations (37 out of 63, 58.7 %) were caused by decompensated placental function manifested by acute obstetrical complications: increasing intrauterine fetal hypoxia (64.9 %) along with intrauterine growth retardation (51.4 %), severe preeclampsia (13.5 %) and premature abruption of the normally located placenta (5.0 %). In both study groups, COVID-19 experienced at 14–16 weeks of pregnancy was associated with coagulation and fibrinolytic imbalances. At the same time, at least 6 weeks post-COVID-19 infection, patients with PB had higher level of the “Peak thrombin” vs. comparison group (3050 vs. 2527 pmol/L; p = 0.0433). Also, patients with term vs. preterm delivery had TF activity decreased significantly: by 47.1% and 28.1%, respectively (p = 0.0546). Patients in preterm delivery group were characterized by fibrinolytic imbalance. At the first time point, suppressed fibrinolysis (PAI-1 level – 18.4 vs. 12.5 ng/ml in the comparison group; p = 0.0209) was concomitant with elevated level of u-PA (1.5 vs. 0.55 ng/ml in comparison group, p = 0.0015), which suggests a potential prolonged immunoinflammatory response in patients with PB. Magnitude of fibrinogen concentration and D-dimer level during post-COVID-19 follow-up study was within the reference values specific to gestational age.Conclusion. A significant increase in coagulation potential was found and verified by elevated activity of tissue factor and potential to thrombin generation in COVID-19 convalescent patients. In the case of preterm delivery, there was an imbalance in fibrinolysis system revealed by decreased blood fibrinolytic activity elevating along with increasing gestational age.

449. Elevated Lactate Dehydrogenase in Convalescent Severe COVID-19 Patients Reflects Delayed Clinical Recovery and Activated Th1 and Th17 Responses

Abstract Background Elevated lactate dehydrogenase (LD) levels during acute phase of COVID-19 is known to reflect multiple organ injuries and clinical severity. However, clinical implication and origin of elevated LD after convalescence have not been elucidated. Methods We prospectively enrolled non-vaccinated severe COVID-19 patients with an oxygen demand greater than FiO2 0.4 and followed them up to one year after discharge. Laboratory values and modified Medical Research Council (mMRC) dyspnea scale were collected at each outpatient visit. To investigate the potential association between elevated LD levels and CD4+T cell activities, fluorescence-activated cell sorting (FACS) and intracellular cytokine staining (ICS) of INF-γ, TNF-α, IL-4, and IL-17A were conducted. Results A total of 74 patients were included, of which 46 (62%) were male, the median age was 59 years (IQR 52–69), and peak FiO2 during hospitalization was 0.65 (IQR 0.50–0.80). At discharge, median absolute lymphocyte count (ALC) was 1.29 x103/μL (IQR 0.93–1.75), median C-reactive protein (CRP) was 0.23 mg/dL (IQR 0.06–0.52), and median LD was 334 IU/L (IQR 276–450). After discharge, ALC increased (R2 = 0.1434, P < 0.001) and LD decreased (R2 = 0.0838, P < 0.001) overtime, but CRP level did not show time-dependent changes (Figure 1A-C). Increased LD (R2 = 0.160, P < 0.001) and CRP (R2 = 0.028, P = 0.024) levels were significantly associated with higher grade of mMRC scales, while ALC was not associated with mMRC scale (Fig 1D-F). To investigate the potential association between elevated LD level and CD4+T cell activation, serial 38 PBMC specimens from 10 patients were further investigated. CD4+T cells were identified using FACS gating and then stained for intracellular cytokines. The proportion of TNF-α+CD4+T cells (R2 = 0.547, P < 0.001; Fig 2A) and IL-17A+CD4+T cells (R2 = 0.419, P = 0.009; Fig 2B) after spike protein stimulation were positively correlated with LD levels, while the proportion of Treg did not.Figure 1.Time-dependent changes in ALC, CRP and LD levels and their association with the degree of dyspnea (mMRC scale) after discharge.(A) Linear regression with ALC and time. (B) Linear regression with CRP and time. (C) Linear regression with LD and time. (D) Linear regression with ALC and mMRC. (E) Linear regression with CRP and mMRC. (F) Linear regression with LD and mMRC. *Statistically significant. ALC, absolute lymphocyte count; CRP, C-reactive protein; LD, lactate dehydrogenase; WBC, white blood cell, mMRC, modified Medical Research Council.Figure 2.FACS gating for CD4+T cells and ICS correlation with serum LD levels after convalescence.FACS gating for CD3+CD4+T cells and ICS for TNF-α (A) and IL-17A (B) were conducted. Serum LD levels after convalescence showed significant correlations with the proportion of TNF-α+CD4+T cells (A) and that of IL-17A+CD4+T cells (B). FACS, fluorescence-activated cell sorting; ICS, intracellular cytokine staining; LD, lactate dehydrogenase. Conclusion Elevated LD in convalescent severe COVID-19 patients reflects delayed clinical recovery and activated Th1 and Th17 responses Disclosures All Authors: No reported disclosures

295. Humanized Mice and Convalescent Humans Yield an Antibody Panel against the Highly Immunogenic Decorin Binding Protein A (DbpA) of the Lyme Disease Spirochete, Borrelia Burgdorferi

Abstract Background Lyme disease is the most commonly diagnosed tick-borne infection, affecting more than 300000 people in the United States annually. The disease is principally caused by the transmission of the spirochete bacteria, by the black-legged (deer) ticks. With a renewed call for interest in a Lyme disease vaccine, antibodies relevance continues due to their efficacy, safety and versatile nature. Humanized mice and humans recovering from the disease have successfully been used to generate therapeutic antibodies against Ebola and SARS-CoV-2 diseases. Methods Our study used humanized mice and convalescent patients to generate recombinant human antibodies that recognize decorin-binding protein A (DbpA), a lipoprotein that is proposed to function as spirochete adhesin. The mAbs expressed as human IgG-Fc fragments were characterized for reactivity with recombinant DbpA, native DbpA on the surface of live Borrelia burgdorferi, borreliacidal activity in the presence of human complement and, finally subject to epitope mapping using an array of methodologies. Results The predominant lineage of humanized mice antibodies utilized VH5-51, VH3-20, VH3-23 and VH3-53 all paired with VK1-33 families. Other common families included VH4-31 paired with VK1-39, VH4-4 and VH4-8 paired with VK-9. The human derived antibody utilized VH3-30 paired with VK1-33. We observed an overlap in the repertoire of kappa chains between humanized mice and human-derived mAbs. Conclusion Combining the humanized mice and human platforms enabled the identification of antibodies with a high binding and specificity to DbpA, which have potential prophylactic and therapeutic properties. Disclosures All Authors: No reported disclosures

Rapid transient and longer-lasting innate cytokine changes associated with adaptive immunity after repeated SARS-CoV-2 BNT162b2 mRNA vaccinations.

Cytokines and chemokines play an important role in shaping innate and adaptive immunity in response to infection and vaccination. Systems serology identified immunological parameters predictive of beneficial response to the BNT162b2 mRNA vaccine in COVID-19 infection-naïve volunteers, COVID-19 convalescent patients and transplant patients with hematological malignancies. Here, we examined the dynamics of the serum cytokine/chemokine responses after the 3rd BNT162b2 mRNA vaccination in a cohort of COVID-19 infection-naïve volunteers. We measured serum cytokine and chemokine responses after the 3rd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in COVID-19 infection-naïve individuals by a chemiluminescent assay and ELISA. Anti-Spike binding antibodies were measured by ELISA. Anti-Spike neutralizing antibodies were measured by a pseudotype assay. Comparison to responses found after the 1st and 2nd vaccinations showed persistence of the coordinated responses of several cytokine/chemokines including the previously identified rapid and transient IL-15, IFN-γ, CXCL10/IP-10, TNF-α, IL-6 signature. In contrast to the transient (24hrs) effect of the IL-15 signature, an inflammatory/anti-inflammatory cytokine signature (CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CXCL8/IL-8, IL-1Ra) remained at higher levels up to one month after the 2nd and 3rd booster vaccinations, indicative of a state of longer-lasting innate immune change. We also identified a systemic transient increase of CXCL13 only after the 3rd vaccination, supporting stronger germinal center activity and the higher anti-Spike antibody responses. Changes of the IL-15 signature, and the inflammatory/anti-inflammatory cytokine profile correlated with neutralizing antibody levels also after the 3rd vaccination supporting their role as immune biomarkers for effective development of vaccine-induced humoral responses. These data revealed that repeated SARS-Cov-2 BNT162b2 mRNA vaccination induces both rapid transient as well as longer-lasting systemic serum cytokine changes associated with innate and adaptive immune responses. Clinicaltrials.gov, identifier NCT04743388.

Salivary IgA and vimentin differentiate in vitro SARS-CoV-2 infection: A study of 290 convalescent COVID-19 patients

SARS-CoV-2 initially infects cells in the nasopharynx and oral cavity. The immune system at these mucosal sites plays a crucial role in minimizing viral transmission and infection. To develop new strategies for preventing SARS-CoV-2 infection, this study aimed to identify proteins that protect against viral infection in saliva. We collected 551 saliva samples from 290 healthcare workers who had tested positive for COVID-19, before vaccination, between June and December 2020. The samples were categorized based on their ability to block or enhance infection using in vitro assays. Mass spectrometry and enzyme-linked immunosorbent assay experiments were used to identify and measure the abundance of proteins that specifically bind to SARS-CoV-2 antigens. Immunoglobulin (Ig)A specific to SARS-CoV-2 antigens was detectable in over 83% of the convalescent saliva samples. We found that concentrations of anti-receptor-binding domain IgA >500 pg/µg total protein in saliva correlate with reduced viral infectivity in vitro. However, there is a dissociation between the salivary IgA response to SARS-CoV-2, and systemic IgG titers in convalescent COVID-19 patients. Then, using an innovative technique known as spike-baited mass spectrometry, we identified novel spike-binding proteins in saliva, most notably vimentin, which correlated with increased viral infectivity in vitro and could serve as a therapeutic target against COVID-19.

Post-coronavirus disease-19: the impact of cardiopulmonary rehabilitation on arterial stiffness, left ventricular deformation, and ventricular-arterial coupling

Abstract Introduction Although coronavirus disease-19 (COVID-19) is a primarily a respiratory disease, impairment of cardiovascular function has been documented, even in the post-acute phase. Cardiopulmonary rehabilitation could represent an appealing approach in the management of cardiovascular sequelae of post-COVID-19, which may affect arterial and left ventricular function, ultimately influencing ventricular-arterial coupling (VAC). Purpose In this study, we assess the impact of a post-acute COVID-19 rehabilitation program on arterial stiffness, left ventricular deformation, and VAC. Methods We enrolled 60 convalescent patients from COVID-19 and one-month post-acute disease were randomized at 1:1 ratio in a 3-month cardiopulmonary rehabilitation program (study group) or not (control group). The levels of pro-inflammatory interleukin-1β (IL-1β) were determined. Arterial stiffness was evaluated by carotid-femoral Pulse wave velocity (cf-PWV) at 1 month and at 4 months post-acute disease. Transthoracic echocardiography was performed, and left ventricular global longitudinal strain (LV-GLS) was estimated. Finally, the ratio of cf-PWV/LV-GLS was calculated as an index of VAC. Results There were no significant differences in major risk factors across the studied groups (age, sex, body mass index, smoking, hypertension, diabetes mellitus, dyslipidemia). Moreover, patients across the study groups did not differ regarding the levels of IL-1β. Although cf-PWV was similar in the study and the control group at baseline, it was improved only in the study group (8.2±1.3m/sec vs. 6.6±1.0m/sec, p<0.001) but not in the control group (8.9±1.8m/sec vs. 8.8±1.9m/sec, p=0.74). Similarly, for GLS, no differences were noted at baseline. However, the study group exhibited a significant improvement during the study (-19.6±2.0% vs. -21.3±1.9%, p<0.001), while no changes were observed in the control group (-18.7±2.9% vs. -18.3±2.1%, p=0.15). Finally, VAC was significantly ameliorated only in patients receiving cardiopulmonary rehabilitation (-0.43±0.11m/s% vs. -0.31±0.06m/s%, p<0.001). When individuals undergoing cardiopulmonary rehabilitation were stratified according to median baseline IL-1β levels, those presenting with lower concentrations experienced a significant benefit in ΔVAC (IL-1β<8.4pg/ml: 0.14±0.08m/s% vs. IL-1β≥8.4pg/ml: 0.09±0.05m/s%, p=0.04). Conclusion A 3-month cardiopulmonary rehabilitation program following the acute phase of COVID-19 accelerates the recovering of arterial and ventricular function, especially in individuals with a lower baseline inflammatory burden.

Blood T cell phenotypes correlate with fatigue severity in post-acute sequelae of COVID-19.

Post-acute sequelae of COVID-19 (PASC) affect approximately 10% of convalescent patients. The spectrum of symptoms is broad and heterogeneous with fatigue being the most often reported sequela. Easily accessible blood biomarkers to determine PASC severity are lacking. Thus, our study aimed to correlate immune phenotypes with PASC across the severity spectrum of COVID-19. A total of 176 originally immunonaïve, convalescent COVID-19 patients from a prospective cohort during the first pandemic phase were stratified by initial disease severity and underwent clinical, psychosocial, and immune phenotyping around 10weeks after first COVID-19 symptoms. COVID-19-associated fatigue dynamics were assessed and related to clinical and immune phenotypes. Fatigue and severe fatigue were commonly reported irrespective of initial COVID-19 severity or organ-specific PASC. A clinically relevant increase in fatigue severity after COVID-19 was detected in all groups. Neutralizing antibody titers were higher in patients with severe acute disease, but no association was found between antibody titers and PASC. While absolute peripheral blood immune cell counts in originally immunonaïve PASC patients did not differ from unexposed controls, peripheral CD3+CD4+ T cell counts were independently correlated with fatigue severity across all strata in multivariable analysis. Patients were at similar risk of self-reported PASC irrespective of initial disease severity. The independent correlation between fatigue severity and blood T cell phenotypes indicates a possible role of CD4+ T cells in the pathogenesis of post-COVID-19 fatigue, which might serve as a blood biomarker.

Serum antibody levels to SARS-CoV-2 receptor-binding domain (RBD) in convalescent patients and vaccinated individuals of northern Nevada.

Antibodies reactive with the SARS-CoV-2 receptor-binding domain (RBD) of the spike protein are associated with viral neutralization, however low antibody titers, specifically against SARS-CoV-2 variants, may result in reduced viral immunity post naturally acquired infection. A cohort study comprised of 121 convalescent individuals from northern Nevada was conducted looking at anti-RBD antibody levels by enzyme-linked immunosorbent assay. Serum was collected from volunteers by staff at the University of Nevada, Reno School of Medicine Clinical Research Center and assessed for antibodies reactive to various SARS-CoV-2 RBD domains relevant to the time of the study (2020-2021). A nonpaired group of vaccinated individuals were assessed in parallel. The goal of the study was to identify antibody levels against the RBD subunit in convalescent and vaccinated individuals from northern Nevada.

Dissecting the intricacies of human antibody responses to SARS-CoV-1 and SARS-CoV-2 infection

The 2003 severe acute respiratory syndrome coronavirus (SARS-CoV-1) causes more severe disease than SARS-CoV-2, which is responsible for COVID-19. However, our understanding of antibody response to SARS-CoV-1 infection remains incomplete. Herein, we studied the antibody responses in 25 SARS-CoV-1 convalescent patients. Plasma neutralization was higher and lasted longer in SARS-CoV-1 patients than in severe SARS-CoV-2 patients. Among 77 monoclonal antibodies (mAbs) isolated, 60 targeted the receptor-binding domain (RBD) and formed 7 groups (RBD-1 to RBD-7) based on their distinct binding and structural profiles. Notably, RBD-7 antibodies bound to a unique RBD region interfaced with the N-terminal domain of the neighboring protomer (NTD proximal) and were more prevalent in SARS-CoV-1 patients. Broadly neutralizing antibodies for SARS-CoV-1, SARS-CoV-2, and bat and pangolin coronaviruses were also identified. These results provide further insights into the antibody response to SARS-CoV-1 and inform the design of more effective strategies against diverse human and animal coronaviruses.

Convalescent Plasma for Covid-19–Induced ARDS in Mechanically Ventilated Patients

BackgroundPassive immunization with plasma collected from convalescent patients has been regularly used to treat coronavirus disease 2019 (Covid-19). Minimal data are available regarding the use of convalescent plasma in patients with Covid-19–induced acute respiratory distress syndrome (ARDS).MethodsIn this open-label trial, we randomly assigned adult patients with Covid-19–induced ARDS who had been receiving invasive mechanical ventilation for less than 5 days in a 1:1 ratio to receive either convalescent plasma with a neutralizing antibody titer of at least 1:320 or standard care alone. Randomization was stratified according to the time from tracheal intubation to inclusion. The primary outcome was death by day 28.ResultsA total of 475 patients underwent randomization from September 2020 through March 2022. Overall, 237 patients were assigned to receive convalescent plasma and 238 to receive standard care. Owing to a shortage of convalescent plasma, a neutralizing antibody titer of 1:160 was administered to 17.7% of the patients in the convalescent-plasma group. Glucocorticoids were administered to 466 patients (98.1%). At day 28, mortality was 35.4% in the convalescent-plasma group and 45.0% in the standard-care group (P=0.03). In a prespecified analysis, this effect was observed mainly in patients who underwent randomization 48 hours or less after the initiation of invasive mechanical ventilation. Serious adverse events did not differ substantially between the two groups.ConclusionsThe administration of plasma collected from convalescent donors with a neutralizing antibody titer of at least 1:160 to patients with Covid-19–induced ARDS within 5 days after the initiation of invasive mechanical ventilation significantly reduced mortality at day 28. This effect was mainly observed in patients who underwent randomization 48 hours or less after ventilation initiation. (Funded by the Belgian Health Care Knowledge Center; ClinicalTrials.gov number, NCT04558476.)

Gag Virus-like Particles Functionalized with SARS-CoV-2 Variants: Generation, Characterization and Recognition by COVID-19 Convalescent Patients' Sera.

The robustness, safety, versatility, and high immunogenicity of virus-like particles (VLPs) make them a promising approach for the generation of vaccines against a broad range of pathogens. VLPs are recombinant macromolecular structures that closely mimic the native conformation of viruses without carrying viral genetic material. Particularly, HIV-1 Gag-based VLPs are a suitable platform for the presentation of the SARS-CoV-2 Spike (S) protein on their surface. In this context, this work studies the effect of different rationally engineered mutations of the S protein to improve some of its characteristics. The studied variants harbored mutations such as proline substitutions for S stabilization, D614G from the early dominant pandemic form, the elimination of the S1/S2 furin cleavage site to improve S homogeneity, the suppression of a retention motif to favor its membrane localization, and cysteine substitutions to increase its immunogenicity and avoid potential undesired antibody-dependent enhancement (ADE) effects. The influence of the mutations on VLP expression was studied, as well as their immunogenic potential, by testing the recognition of the generated VLP variants by COVID-19 convalescent patients' sera. The results of this work are conceived to give insights on the selection of S protein candidates for their use as immunogens and to showcase the potential of VLPs as carriers for antigen presentation.

Presence of Elevated Interleukin – 6 (IL-6) in the Blood of COVID-19 Convalescent Patients (40 – 93 Days) Post Onset of Symptoms Could be an Indicator of Ongoing Activation of the Immune System

IL-6 concentrations rise with the onset of COVID-19 infection and is detected in 68% of patients on admission but is expected to reduce after the acute phase. IL-6 concentrations at time points: (2-7 days), (6-11 days), (11-15 days) and (13-20 days) after intensive care unit (ICU) admission showed the highest level of IL-6 concentrations at time point 2-7 days, we decided to characterize IL-6 concentrations in serum samples collected in the sera of COVID-19 convalescent patients (40 – 93 days) post onset of symptoms. The estimated IL- 6 concentrations detected ranged between 2.65 pg/ml and 29.01 pg/ml, with a median of 9.18 pg/ml. Nine out of the 28 (32.14%) patients had normal IL-6 levels (<7 pg/ml) and 19 of the 28 patients (68%) had IL-6 elevated concentrations (>7 pg/ml). The IL-6 concentrations were grouped normal (<7 pg.ml, n= 9), mildly elevated (7 – 10 pg/ml, n = 10) and elevated (>10 pg/ml n = 9). There was no relationship between IL-6 concentrations with gender, days from onset of symptoms, days from subsiding symptoms and COVID-19 IgG antibodies. There was some relationship with age, as the younger patient cohort produced much higher IL-6 concentrations than the older patient cohort. This study describes an increase in blood IL-6 concentrations in the sera of COVID-19 convalescent patients (40 – 93 days) post onset of symptoms like that seen in COVID patients on admission and higher levels seen in the younger patient cohort indicating that “cytokine storms” still occur in the recovery phase.

First-in-human immunoPET imaging of COVID-19 convalescent patients using dynamic total-body PET and a CD8-targeted minibody.

With most of the T cells residing in the tissue, not the blood, developing noninvasive methods for in vivo quantification of their biodistribution and kinetics is important for studying their role in immune response and memory. This study presents the first use of dynamic positron emission tomography (PET) and kinetic modeling for in vivo measurement of CD8+ T cell biodistribution in humans. A 89Zr-labeled CD8-targeted minibody (89Zr-Df-Crefmirlimab) was used with total-body PET in healthy individuals (N = 3) and coronavirus disease 2019 (COVID-19) convalescent patients (N = 5). Kinetic modeling results aligned with T cell-trafficking effects expected in lymphoid organs. Tissue-to-blood ratios from the first 7 hours of imaging were higher in bone marrow of COVID-19 convalescent patients compared to controls, with an increasing trend between 2 and 6 months after infection, consistent with modeled net influx rates and peripheral blood flow cytometry analysis. These results provide a promising platform for using dynamic PET to study the total-body immune response and memory.

Hantavirus: an overview and advancements in therapeutic approaches for infection.

Hantaviruses are a significant and emerging global public health threat, impacting more than 200,000 individuals worldwide each year. The single-stranded RNA viruses belong to the Hantaviridae family and are responsible for causing two acute febrile diseases in humans: Hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS). Currently, there are no licensed treatments or vaccines available globally for HTNV infection. Various candidate drugs have shown efficacy in increasing survival rates during the early stages of HTNV infection. Some of these drugs include lactoferrin, ribavirin, ETAR, favipiravir and vandetanib. Immunotherapy utilizing neutralizing antibodies (NAbs) generated from Hantavirus convalescent patients show efficacy against HTNV. Monoclonal antibodies such as MIB22 and JL16 have demonstrated effectiveness in protecting against HTNV infection. The development of vaccines and antivirals, used independently and/or in combination, is critical for elucidating hantaviral infections and the impact on public health. RNA interference (RNAi) arised as an emerging antiviral therapy, is a highly specific degrades RNA, with post-transcriptional mechanism using eukaryotic cells platform. That has demonstrated efficacy against a wide range of viruses, both in vitro and in vivo. Recent antiviral methods involve using small interfering RNA (siRNA) and other, immune-based therapies to target specific gene segments (S, M, or L) of the Hantavirus. This therapeutic approach enhances viral RNA clearance through the RNA interference process in Vero E6 cells or human lung microvascular endothelial cells. However, the use of siRNAs faces challenges due to their low biological stability and limited in vivo targeting ability. Despite their successful inhibition of Hantavirus replication in host cells, their antiviral efficacy may be hindered. In the current review, we focus on advances in therapeutic strategies, as antiviral medications, immune-based therapies and vaccine candidates aimed at enhancing the body's ability to control the progression of Hantavirus infections, with the potential to reduce the risk of severe disease.

Autoreactive T cells targeting type II pneumocyte antigens in COVID-19 convalescent patients

BackgroundThe role of autoreactive T cells on the course of Coronavirus disease-19 (COVID-19) remains elusive. Type II pneumocytes represent the main target cells of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Autoimmune responses against antigens highly expressed in type II pneumocytes may influence the severity of COVID-19 disease. ObjectiveThe aim of this study was to investigate autoreactive T cell responses against self-antigens highly expressed in type II pneumocytes in the blood of COVID-19 patients with severe and non-severe disease. MethodsWe collected blood samples of COVID-19 patients with varying degrees of disease severity and of pre-pandemic controls. T cell stimulation assays with peptide pools of type II pneumocyte antigens were performed in two independent cohorts to analyze the autoimmune T cell responses in patients with non-severe and severe COVID-19 disease. Target cell lysis assays were performed with lung cancer cell lines to determine the extent of cell killing by type II PAA-specific T cells.Results: We identified autoreactive T cell responses against four recently described self-antigens highly expressed in type II pneumocytes, known as surfactant protein A, surfactant protein B, surfactant protein C and napsin A, in the blood of COVID-19 patients. These antigens were termed type II pneumocyte-associated antigens (type II PAAs). We found that patients with non-severe COVID-19 disease showed a significantly higher frequency of type II PAA-specific autoreactive T cells in the blood when compared to severely ill patients. The presence of high frequencies of type II PAA-specific T cells in the blood of non-severe COVID-19 patients was independent of their age. We also found that napsin A-specific T cells from convalescent COVID-19 patients could kill lung cancer cells, demonstrating the functional and cytotoxic role of these T cells. ConclusionsOur data suggest that autoreactive type II PAA-specific T cells have a protective role in SARS-CoV-2 infections and the presence of high frequencies of these autoreactive T cells indicates effective viral control in COVID-19 patients. Type II-PAA-specific T cells may therefore promote the killing of infected type II pneumocytes and viral clearance.

Raman spectroscopic analysis of human serum samples of convalescing COVID-19 positive patients

Rapid screening, detection and monitoring of viral infection is of critical importance, as exemplified by the rapid spread of SARS-CoV-2, leading to the worldwide pandemic of COVID-19. This is equally the case for the stages of patient convalescence as for the initial stages of infection, to understand the medium and long terms effects, as well as the efficacy of therapeutic interventions. Optical spectroscopic techniques potentially offer an alternative to currently employed techniques of screening for the presence, or the response to infection. In this study, the ability of Raman spectroscopy to distinguish between samples of the serum of convalescent COVID-19 positive patients and COVID-19 negative serum samples, and to further analyse and quantify systemic responses, was explored. The study included serum samples of patients who had been tested for SARS-CoV-2 specific IgG and IgM responses between 25 and 134 days after the infection was identified. Both COVID-19 positive and negative groups included males and females who ranged in age from 21 to 81 years old. No correlation was apparent between the specified SARS-CoV-2 specific IgG and IgM immunoglobulin levels of the positive group, their sex, or age. Raman spectroscopic measurements were performed at 785 nm, in liquid serum, thawed from frozen, and spectra were pre-processed to remove the contribution of water, normalising to the water content. Principal components analysis of the spectral dataset over the range 400–1800 cm-1 provided no clear indication of a difference between normal serum and SARS-CoV-2 positive serum. A selection of 5 of the samples, which were available in sufficient volume, were fractionated by centrifugal filtration, and the 100 kDa, 50 kDa, 30 kDa, and 10 kDa concentrates similarly analysed by Raman spectroscopy. Partial least squares regression analysis revealed a negative correlation between the spectral profile of the 30 kDa fractions and SARS-CoV-2 specific IgG antibody levels, potentially indicating an association with depleted glutathione levels. The study supports a potential role of Raman screening of blood serum for monitoring of SARS-CoV-2 infection, but also in longitudinal studies of disease progression, long term effects, and therapeutic interventions.

A Dynamic Model for Estimating the Retention Duration of Neutralizing Antibody Titers After Vaccination in a COVID-19 Convalescent Population.

We measured neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a cohort of 235 convalescent patients (representing 384 analytic samples). They were followed for up to 588 days after the first report of onset in Taiwan. A proposed Bayesian approach was used to estimate nAb dynamics in patients postvaccination. This model revealed that the titer reached its peak (1819.70 IU/mL) by 161 days postvaccination and decreased to 154.18 IU/mL by day 360. Thus, the nAb titers declined in 6 months after vaccination. Protection, against variant B.1.1.529 (ie, Omicron) may only occur during the peak period.

Lipid metabolism of plasma-derived small extracellular vesicles in COVID-19 convalescent patients

The coronavirus disease 2019 (COVID-19), which affects multiple organs, is causing an unprecedented global public health crisis. Most COVID-19 patients recover gradually upon appropriate interventions. Viruses were reported to utilize the small extracellular vesicles (sEVs), containing a cell-specific cargo of proteins, lipids, and nucleic acids, to escape the attack from the host’s immune system. This study aimed to examine the sEVs lipid profile of plasma of recovered COVID-19 patients (RCs). Plasma sEVs were separated from 83 RCs 3 months after discharge without underlying diseases, including 18 recovered asymptomatic patients (RAs), 32 recovered moderate patients (RMs), and 33 recovered severe and critical patients (RSs), and 19 healthy controls (HCs) by Total Exosome Isolation Kit. Lipids were extracted from sEVs and then subjected to targeted liquid chromatography-mass spectrometry. The size, concentration, and distribution of sEVs did not differ in RCs and HCs as validated by transmission electron microscopy, nanoparticle tracking analysis, and immunoblot analysis. Fifteen subclasses of 508 lipids were detected in plasma sEVs from HCs, RAs, RMs, and RSs, such as phosphatidylcholines (PCs) and diacylglycerols (DAGs), etc. Total lipid intensity displayed downregulation in RCs compared with HCs. The relative abundance of DAGs gradually dropped, whereas PCs, lysophosphatidylcholines, and sphingomyelins were higher in RCs relative to HCs, especially in RSs. 88 lipids out of 241 in sEVs of RCs were significantly different and a conspicuous increase was revealed with disease status. The sEVs lipids alternations were found to be significantly correlated with the clinical indices in RCs and HCs, suggesting that the impact of COVID-19 on lipid metabolism lingered for a long time. The lipid abnormalities bore an intimate link with glycerophospholipid metabolism and glycosylphosphatidylinositol anchor biosynthesis. Furthermore, the lipidomic analysis showed that RCs were at higher risk of developing diabetes and sustaining hepatic impairment. The abnormality of immunomodulation in RCs might still exist. The study may offer new insights into the mechanism of organ dysfunction and help identify novel therapeutic targets in the RCs.

PB0065 Targeting the Endothelium when Treating Convalescent COVID-19 Patients, the Effect on Serum Biomarkers, and Post-COVID Functional Status. Midterm Results of a Randomized, Placebo-Controlled Trial

PB0065 Targeting the Endothelium when Treating Convalescent COVID-19 Patients, the Effect on Serum Biomarkers, and Post-COVID Functional Status. Midterm Results of a Randomized, Placebo-Controlled Trial

Chronic Suppurative Gingivitis: A Rare Manifestation of Lichen Planus Following SARS-COV 2 Infection

Post-COVID-19 chronic suppurative gingivitis is an emerging clinical entity that has attracted increasing interest in the medical and dental community because of its association with SARS-CoV-2 virus infection and its prolonged and potentially debilitating manifestation in the periodontal system. This article provides a comprehensive review of this entity, addressing its epidemiology, pathogenesis, clinical manifestations, diagnosis and current therapeutic approaches. The epidemiology of post-COVID-19 chronic suppurative gingivitis is characterized by its occurrence following SARS-CoV-2 infection, with a variable incidence in convalescent patients. A higher prevalence has been observed in individuals with underlying systemic diseases, such as diabetes mellitus and arterial hypertension, suggesting an individual susceptibility component. From a pathogenic perspective, it has been postulated that SARS-CoV-2 infection could trigger an overactive immune response and chronic inflammation at the gingival level, contributing to persistent suppurative gingivitis. The involvement of viral factors and host response in the pathogenesis of this entity are under ongoing investigation. The clinical presentation of post-COVID-19 chronic suppurative gingivitis includes characteristic signs such as gingivorrhage, gingival edema, superficial ulcerations, and the production of purulent exudate in the gums. These findings, in combination with a history of SARS-CoV-2 infection, are critical for diagnosis.