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.