CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

weeks since the initial infection, negatively impacted daily life and could not be explained otherwise. Results: 112 children were included in the study, including 34 children fulfilling clinical criteria of Long Covid, 32 acute SARS-CoV-2 infection, 27 MIS-C and 19 healthy controls. Compared with controls, pediatric Long Covid was characterized by higher expression of the proinflammatory and pro angiogenetic set of chemokines CXCL11, CXCL1, CXCL5, CXCL6, CXCL8, TNFSF11, OSM, STAMBP1a. A Machine Learning model based on proteomic profile was able to identify LC with an accuracy of 0.93, specificity of 0.86 and sensitivity of 0.97. Conclusions: Pediatric Long Covid patients have a well distinct blood protein signature marked by increased ongoing general and endothelial inflammation, similarly as happens in adults. The figure, table, or graphic for this abstract has been removed. Plasma Biomarkers in Children and Young People With Long COVID Jon Izquierdo-Pujol 1 , Victor Urrea 1 , Maria C. Puertas 1 , Judith Dalmau 1 , Alba González-Aumatell 2 , Clara Carreras-Abad 2 , Maria Méndez 2 , Carlos Rodrigo 2 , Javier Martinez-Pìcado 1 , Sara Morón-López 1 1 IrsiCaixa, Badalona, Spain, 2 Hospital Germans Trias i Pujol, Barcelona, Spain Background: Although most patients infected with SARS-CoV-2 recover, 10-20% can develop long-term persistent symptoms after the acute infection, a condition known as long COVID or Post-Acute Sequalae of SARS-CoV-2 (PASC). In this study we aim to compare autoantibodies, cytokines and neuronal and vascular damage biomarkers in plasma from \ children and young people (CYP) with and without PASC. Methods: We analysed 130 EDTA plasma samples from the pediaCOVID cohort (Hospital Germans Trias i Pujol), which includes 108 CYP diagnosed with PASC and 22 controls (11 infected and 11 uninfected) at 3 months after acute infection. Autoantibodies against the M2 muscarinic and β2 adrenergic G-protein coupled receptors (GPCRs) and the vascular damage biomarkers endothelin-1, angiopoietin-2 and von Willebrand’s Factor were measured using ELISA; 42 inflammatory markers were measured by Luminex (HCYTOMAG-60K, Milliplex® Map Kit) and ELISA (Gal-9), and neuronal damage markers glial fibrillary acidic protein (GFAP) and neurofilaments (NfL) were measured by SIMOA® Technology. Results: CYP with PASC had increased levels of autoantibodies against the β2 adrenergic receptor (p=0.007), a trend towards increased levels of autoantibodies against the M2 muscarinic receptor (p=0.065), and increased levels of the inflammatory markers eotaxin and PDGF-AB (p=0.018 and p=0.047 respectively) while showed decreased levels of RANTES (CCL5) (p=0.010) compared to the infected group. Moreover, CYP from the PASC and infected controls had higher levels of both GM-CSF and IL10 compared to the uninfected group (GM-CSF p=0.014, p=0.020; IL10 p=0.021, p=0.037 respectively). Finally, there were no significant differences in both vascular and neuronal damage biomarkers between CYP with and without PASC. Conclusions: These results demonstrates that CYP with PASC have inflammatory dysregulation and increased levels of autoantibodies, suggesting a potential role of the immune system in pediatric PASC. Interestingly, the β2 muscarinic GPCRs autoantibodies has already been shown to be increased in adults with PASC, suggesting a common link between pediatric and adult PASC physiopathology not shown before. Moreover, our results on vascular and neuronal damage biomarkers suggests that CYP with PASC had no vascular nor neuronal damage at 3 months after the acute infection. More comprehensive studies must be done to decipher if this immune dysregulation is a consequence or a cause of PASC. Key Inflammatory Biomarkers Differentiate MIS-C From Convalescent COVID-19 and Kawasaki Disease Tetyana Pidkova 1 , Rosa Maria Pino Ramirez 2 , Victor Urrea 3 , Marta Vidal 4 , Ruth Aguilar 4 , Gemma Moncunill 4 , Jordi Antón 2 , Carlota Dobaño 4 , Claudia Fortuny Guash 2 , Julià Blanco 3 , Benjamin Trinité 3 1 IrsiCaixa Institute for AIDS Research, Badalona, Spain, 2 Hospital Sant Joan de Déu Barcelona, Esplugues, Spain, 3 IrsiCaixa, Badalona, Spain, 4 Barcelona Institute for Global Health, Barcelona, Spain Background: SARS-CoV-2 infections in children are generally mild or asymptomatic. A significant concern is the post-infectious immune response, particularly multisystem inflammatory syndrome in children (MIS-C). This is a severe complication usually developing 4-6 weeks after infection, likely

triggered by a hyperinflammatory response to SARS-CoV-2. This study analyzed the inflammatory profile in children with acute MIS-C, convalescent COVID-19 children without MIS-C, and acute Kawasaki disease (KD), aiming to differentiate these conditions and understand the immune responses involved. Methods: Serum was collected from Convalescent Control COVID-19 (17 participants, 4-6 weeks post-infection), MIS-C (22 patients, including follow ups at 2 months [n=11] and 18 months [n=15]), and KD (10 acute pre-pandemic patients) and assayed for 92 inflammatory markers using the Olink Target 96 Inflammation panel. Data normalization and statistical analyses, including random forest, PCA, and unsupervised clustering, were performed using R v4.3. Results: The MIS-C and Control COVID-19 groups were balanced by age (median 7.8 and 9.8 years) and gender (females 45.5% and 47%). KD patients had a median age of 3.2, with 30% female. We identified eighteen key cytokines and chemokines differentiating MIS-C from Control COVID-19 , including increased levels of IL-6, IL-10, IL-18, IL-18R, TNF, CXCL9, CXCL10, CXCL11, PD-L1, MCP-3, CDCP1, CCL3, and CD40 and decreased levels of TRANCE, TWEAK, SCF, and NT.3 in acute MIS-C. These markers were consistent across sex, but better classified males (100%) than females (89%). Our cohort had 50% of severe MIS-C cases, and 81.8% of these were males. Six markers (high IL-2, IL-33, and low CD8A, TNFRSF9, CD244, SCF) were linked to severe MIS-C cases. Over time, longitudinal analysis showed inflammatory markers normalazing post-treatment, reaching levels comparable to the Control COVID-19 group. Finally, MIS-C was also distinguished from KD by lower levels of TNFRSF9, TWEAK, and TRAIL. Conclusions: This study offers critical insights into the inflammatory mechanisms of MIS-C, distinguishing it from convalescent COVID-19 and KD, indicating a distinct hyperinflammatory response. Identifying cytokines that predict MIS-C severity or differentiate MIS-C from KD are crucial for improving early diagnosis and treatment. Longitudinal analysis show fast normalization (2 months) of the inflammatory profile post-treatment, suggesting immunological recovery. Immune Profile of Children With Post-COVID-19 Cardiac Contractility Alterations: A Prospective Study Costanza Di Chiara 1 , Anna Cantarutti 2 , Jolanda Sabatino 3 , Domenico Sirico 4 , Francesco Bonfante 5 , Daniele Donà 1 , Anita De Rossi 1 , Carlo Giaquinto 1 , Maria Raffaella Petrara 1 , Giovanni Di Salvo 1 1 University of Padova, Padova, Italy, 2 University of Milano–Bicocca, Milan, Italy, 3 Magna Græcia University of Catanzaro, Catanzaro, Italy, 4 Azienda Ospedaliera di Padova, Padua, Italy, 5 Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy Background: Myocardial injuries have been observed after COVID-19 in previously healthy children, regardless of COVID-19 severity. Immune dysregulation may play a role in post-COVID cardiac alterations but remains unexplored in children. This study evaluated the immune response in children with or without asymptomatic cardiac contractility alterations after mild SARS CoV-2 infection. Methods: A prospective, observational study was conducted at the University of Padua (Italy) from May-September 2020 on children aged 0-<18 years after mild COVID-19. Three months post-COVID-19, speckle-tracking echocardiography assessed cardiac function, and blood samples were collected for immunological analysis. Children with cardiac contractility alterations (C-ACC) were defined by a regional peak systolic strain <-16% in at least two segments. Immune activated and regulatory T (Tregs) cells were analyzed via flow cytometry, while neutralizing antibody (NAb) titers were assessed via the Plaque Reduction Neutralization Test (PRNT). Geometric mean titers (GMTs), 95% confidence intervals (95%CI), medians, and interquartile ranges (IQRs) were compared between C-ACC and children without cardiac contractility alterations (C-NACC). Spearman correlation was assessed between immune activation, Tregs, and NAbs. Results: Sixty-seven children were studied (mean age: 7±4.8 years; male/ female: 28/39), including 16 C-ACC and 51 C-NACC. All C-ACC children had asymptomatic cardiac contractility alterations with normal left ventricular ejection fraction. No differences in systemic symptoms were found between C-ACC and C-NACC (11/16 [68.8%] vs 31/51 [60.8%]; p=ns). Notably, C-ACC exhibited lower Treg frequencies (3.17 [IQR: 1.26-5.6] vs 6.96 [IQR: 3.55-11.57]) and shorter telomeres (4.82 [IQR: 3.57-5.81] vs 6.28 [IQR: 4.03-7.69]) compared to C-NACC. At similar activated CD8 cell frequencies between the two groups, an inverse correlation between Tregs and activated CD8 cells was observed in C-NACC (r=-0.476) (Figure). NAb titers were higher in C-NACC than in C-ACC

940

Poster Abstracts

942

941

CROI 2025 295