Over 100 proteins (137 to be precise) are linked to severe forms of Covid-19 which, albeit rarely, can affect children. They have been identified by the authors of a study led by the Murdoch Children’s Research Institute-Mcri and the University of Melbourne, Australia, published in ‘Nature Communications’. The work – they explain – made it possible to identify for the first time the pathogenetic mechanisms at the origin of the multisystemic inflammatory syndrome that attacks vital organs such as the heart, lungs and brain, and of the acute respiratory distress syndrome that damages the lungs. The biological pathways involved are those of blood coagulation and the immune response to the Sars-CoV-2 virus, and having discovered them opens the way to earlier diagnoses and more targeted treatments. “In general, children are less susceptible to Covid-19 and have milder symptoms, but the factors that in some can lead to the development of very serious diseases are not clear – recalls Conor McCafferty, Mcri researcher and PhD student at the University of Melbourne – Our study is the first to discover the specific pathways of blood clotting and immunity that play a role in children affected by severe Covid. ” For the investigation, blood samples were collected from 20 healthy children at the Royal Children’s Hospital of Melbourne and from 33 children with Sars-CoV-2 infection, multisystem inflammatory syndrome or acute respiratory distress syndrome at Hôpital Necker-Enfants Malades, Greater Paris University Hospitals, France. Scientists from the Australian Proteome Analysis Facility in Sydney also contributed to the research. Thanks to proteomics, an experimental approach that allowed the simultaneous evaluation of almost 500 circulating proteins in the blood, the authors detected 85 proteins specific for multisystem inflammatory syndrome and 52 for acute respiratory distress syndrome. The study found that for 1.7% of hospitalized pediatric Covid patients, hospitalization included intensive care. Notably, children with multisystem inflammatory syndrome exhibited clinical features similar to Kawasaki disease and toxic shock syndrome, such as fever, abdominal pain, vomiting, rash, and conjunctivitis, making rapid symptom-based diagnosis difficult. This is why according to Vera Ignjatovic, Mcri professor, the results of the new work could help to develop diagnostic tests for the timely identification of the children most at risk, as well as to identify therapeutic targets for more effective treatments. “Know the mechanisms associated with Covid -19 serious in children, and knowing how the blood clotting and the immune system of the little ones react to the Sars-CoV-2 virus – the expert points out – will help to recognize acute cases of Covid and will allow us to develop a targeted treatment ” .