Análise de potenciais biomarcadores ligados a resposta imunológica em pacientes com Covid-19

Abstract

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection leads to several clinical outcomes, including death. One possible hypothesis for such clinical variations could be due to an exaggerated immune response. Previous studies showed that in patients with severe lung inflammation, the number of cytotoxic T cells is reduced, presenting exhausted phenotypes and impaired functionality. Therefore, we aimed to investigate the prognostic value of plasmatic and cellular changes correlated with the immune response. The study was observational with 75 human subjects, and the approval of the human research ethics committee (30732120.1.0000.5013). From the total amount, 57 samples were from patients admitted to the Hospital Universitário Professor Alberto Antunes da Universidade Federal de Alagoas (HUPAA/UFAL) (COVID-19 group), and 19 donators (Control group) with paired ages, sex, and comorbidities. We conducted hematological and biochemical blood analysis, plasmatic analysis by Raman spectroscopy and by flow cytometry bead assay for sFas, sFasL, perforin, granulysin, and granzymes (Gzm) A and B, and immunophenotyping for lymphocytes and lymphoid cells subpopulations. The results indicated that the COVID-19 group presented several altered hematological and biochemical parameters which were predictive for severity and mortality. In Raman spectroscopy, we observed a reduction in spectra attributed to aminoacids (phenylalanine [p ≤ 0.001], proline [p ≤ 0.05], tryptophan [p ≤ 0.01], and tyrosine [p ≤ 0.01]) and carotenoids (p ≤ 0.05), whereas an increase in a single spectrum attributed to lipids was observed as well (p ≤ 0.001). The COVID-19 group had increased levels of GzmA (p =0,04) and GzmB (p =0.01), although the GzmB was the molecule that most contributed to groups discrimination (21.43 covariance; 0.81 correlation). The GzmB also was elevated in the elderly (p = 0.01) and explains 81.7% of the variance between discharge and death. It also detected increased amounts of innate lymphoid cells (ILC)1 and ILC3 (p ≤ 0.05), and reduction of naive and memory effector T CD4+ cells, and effector and memory effector T CD8+ cells (p ≤ 0.01). Our results indicate that the granzymes are acting in their extracellular functions corroborating with the course of the disease and that they can be employed as worse prognosis markers for COVID-19.