Introduction
Already from the first pandemic months, it became evident that clinical manifestations of SARS-COV-2 infection in pediatric patients were strongly differentiated compared to adults(1). Very few children progress to any significant respiratory distress(2,3), however a small percentage of pediatric patients presents multisystem inflammatory syndrome(4,5) as a post infectious complication. Similar to adults, a part of the convalescent COVID-19 pediatric population presents multisystemic nonspecific symptoms, mental health problems and a reduction in quality of life similar to ME/CFS and long COVID-19 symptomatic(6). However, current reports are conflicting regarding its direct or indirect connection to SARS-CoV-2 prevalence, duration and impact on daily life(1). Sorg et al and Borch et al report ME/CFS similar symptomatic in seronegative and seropositive SARS-CoV-2 children and suggest that containment measures and reduction of social contacts during 2020 and 2021 reflect on these results(6,7).
Independent observational studies conclude that the main symptoms/diagnoses of PASC among children are exertional dyspnea, cough and exercise intolerance, loss of taste/smell, fatigue and to a lesser extend muscle weakness and chest pain (8–14).
Studies in adult subjects with PASC manifestation suggest chronic stimulation of the immune system as a result of antigen persistence, autoimmunity or microbiota-gut-brain axis dysregulation(15–17). However, data regarding the pathology and immune mechanisms behind pediatric PASC is scarce. To address these knowledge gaps and the contribution of immunity, including humoral and cellular response in pediatric PASC pathogenesis, we performed a comprehensive immune profiling of 17 pediatric patients with PASC. As control we used 13 healthy COVID-19 convalescent children.