Immune profiling of COVID-19 infection in pediatric solid organ transplantation

Abstract

Abstract Background: We describe the clinical presentation & immune response to COVID-19 infection in pediatric SOT. Method: Medical records of COVID-19 PCR+ & seropositive patients (SP) were reviewed for details of their disease course. Blood was obtained during PCR or seropositivity for immunophenotyping. Controls were pediatric solid organ transplant (SOT) patients with negative COVID-19 (NCs) status. As induction of immunological memory is central to anti-pathogen adaptive immunity induced by infection, immunohistochemistry of liver tissue for tissue resident memory cells (TRM) was performed. Results: 15 patients had COVID positive status (7 PCR+ & 8 SP) between March 2020 & January 2021. 4 symptomatic PCR+ patients were hospitalized for 24–72-hours & 1 symptomatic SP patient had a prolonged PICU stay. Infrequent TRM were seen in liver biopsies of PCR+ & SP patients vs. biopsies from same patients that pre-date a COVID-19+ status. Patients with COVID + status appeared to segregate into 2 groups: 1 group with activated CD4+ response, & the 2nd group lacking obvious activated CD4+ response, similar to NC patients (n=16). The PCR+ patients expressed significantly less CD4+ & CD8+ IFN-γ compared to the SP patients (p=0.009; p=0.01 respectively). Similarly, activated CD8 “EMRAs” was significantly lower in PCR+ patients compared to SP patients (p=0.01). Conclusion: COVID-19 infection in pediatric SOT patients is generally mild with notable increased frequency of CD8+ “EMRAs” & IFN-γ in SP patients, presumably a result of antigen-experienced cells.