[Objective: The X chromosome contains the largest number of immune-related genes which play a major role in Coronavirus disease 2019 (COVID-19) symptomatology and susceptibility. Here, we had a unique opportunity to investigate, for the first time, COVID-19 outcomes in six unvaccinated Brazilian young patients with Turner Syndrome (TS) (45, X0), including one case of critical illness in a 10-year-old child, aiming to evaluate their immune response according to their genetic profile. Methods: Serological analysis of humoral immune response against SARS-CoV-2; phenotypic characterization of antiviral responses in peripheral blood mononuclear cells after stimuli, and the production of cytotoxic cytokines of T lymphocytes and NK cells, were performed in blood samples collected from the TS patients during the convalescence period. Whole-exome sequencing (WES) was also performed. Results: Our TS volunteers showed a delayed or insufficient humoral immune response to SARS-CoV-2 (particularly IgG) and a decrease in IFN-γ production by CD4+ and CD8+ T lymphocytes after stimulation with TLR7/TLR8 agonists. In contrast, we observed a higher cytotoxic activity in the TS volunteers compared to the non-TS volunteers after PMA/ionomycin stimulation, particularly granzyme B and perforin by CD8+ and NK cells. Interestingly, two TS volunteers carry rare genetic variants in genes that regulate type I and III IFN immunity. Conclusion: Following previous reports in the literature for other conditions, our data showed that TS patients may have an impaired immune response against SARS-CoV-2. Furthermore, other medical conditions associated with TS could make them more vulnerable to COVID-19]

Fuente: International Journal of Infectious Diseases
Available online 8 February 2023