The mechanisms of milder clinical symptoms of COVID-19 in children compared to adults.

In stark contrast to adult patients, children who contract Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) typically manifest milder symptoms or remain asymptomatic. However, the precise underlying mechanisms of this pathogenesis remain elusive. In this review, we primarily retrospect the clinical characteristics of SARS-CoV-2 infection in children, and explore the factors that may contribute to the typically milder clinical presentation in pediatric Coronavirus Disease 2019 (COVID-19) patients compare with adults patients with COVID-19. The pathophysiological mechanisms that mitigate lung injury in children are as follows: the expression level of ACE2 receptor in children is lower; the binding affinity between ACE2 receptors and viral spike proteins in children was weaker; children have strong pre-activated innate immune response and appropriate adaptive immune response; children have more natural lymphocytes; children with COVID-19 can produce higher levels of IgM, IgG and interferon; children infected with SARS-CoV-2 can produce lower levels of IL-6 and IL-10; children have fewer underlying diseases and the lower risk of worsening COVID-19; children are usually exposed to other respiratory viruses and have an enhanced cross-reactive immunity. Comprehending the relative contributions of these processes to the protective phenotype in the developing lungs can help in the diagnosis, treatment and research pertaining to children with COVID-19.

PD-1 inhibitors-associated myocarditis in non-small cell lung cancer patients.

Background: Immune checkpoint inhibitors (ICIs)-associated myocarditis remains a rare but fatal adverse event. The authors sought to provide a comprehensive clinical description of ICI-associated myocarditis by analyzing symptoms, laboratory indicators, imaging features, and management of ICI-associated myocarditis in patients with non-small cell lung cancer (NSCLC). Methods: A retrospective study was conducted to analyze 14 ICI-associated myocarditis cases and 45 control patients to clarify clinical features of ICI-associated myocarditis. Detailed laboratory tests and imaging examinations were performed in 14 cases, and the rescue process and follow-up after the onset of myocarditis were recorded. Results: A total of 14 (2.08%) NSCLC patients developed ICI-related myocarditis, with a median time of onset of 34 days (interquartile range, 12 to 146 days) after ICI initiation. The most common concurrent adverse events in cases were myositis (P<0.001) and peripheral neuritis (P<0.001). Among cases, cardiac troponin I (cTnI) levels were abnormally elevated in 92% of patients, and electrocardiogram (ECG) showed abnormal in all cases. Steroid therapy was used in 92.9% of patients with ICI-associated myocarditis, of which the response rate to steroids was 76.9% and the mortality rate was 7.1%. A dose of 1 g/d of glucocorticoid supplemented by immunoglobulin was observed to be effective for severe myocarditis. Conclusions: Early identification and treatment are essential for managing myocarditis caused by ICI. Routine monitoring of cTnI level and ECG is most sensitive for the early diagnosis of ICI-related myocarditis. High-dose of glucocorticoids can effectively relieve the symptoms of ICI-associated myocarditis and stabilize the condition, especially for fulminant myocarditis.