Avaliação de biomarcadores bucais e salivares em pacientes com COVID-19

Abstract

Objective: The objectives of the present study were: a) to evaluate the morphological aspects of the tongue dorsum epithelial cells and the expression of the Spike SARS-CoV-2 protein in these cells, in patients with and without COVID-19; b) also evaluate the presence and levels of IgG and IgA in the saliva of control patients before the pandemic, negative and convalescent for COVID-19. Methods: individuals with at least one symptom of covid-19 were recruited from. Patients testing positive for covid-19 by RT-PCR were included in the case group and those testing negative were included in the control group to assess spike protein expression. Cytological smears from the dorsum of the tongue were obtained from the patients and analyzed by immunohistochemistry directed against the spike protein of Sars-Cov-2. Morphological changes in epithelial cells were analyzed under light microscopy. In the assessment of antibodies, the study participants were divided into 4 groups, Group 1 - Pre-COVID-19, Group 2 - Negative, Group 3 - Convalescent <1 month, and Group 4 - Convalescent >3 months. Saliva samples were collected by the patient himself in a steril universal collector. Igg and iga present in saliva were tested using indirect elisa against recombinant human sars-cov-2 s1 protein. Results: Immunohistochemistry showed that 71% of patients with COVID-19 had epithelial cells positive for the presence of the SARS-CoV-2 Spike protein, and all cells from patients in the control group were negative. Cytological analysis showed significant differences when comparing epithelial cells from COVID-19 positive and negative patients. In the salivary evaluation through ELISA, it was observed that although there were no statistically significant differences between the groups with samples collected after the beginning of the pandemic, group 3 was the group with the highest levels of IgG and IgA, groups 4 and 2 also expressed IgG and IgA, but in a smaller proportion. However, significant differences were observed in IgG levels in groups 2, 3 and 4 compared to group 1. Regarding IgA levels, there was no significant difference in antibody levels. There was a significantly higher percentage of individuals positive for IgG and IgA against Sars-Cov-2 in saliva in patients convalescent from COVID-19 than in controls. Conclusion: COVID-19 can generate dimensional changes in tongue epithelial cells; however, more studies are needed to understand how this happens. The use of saliva as a non-invasive method for collecting biological samples has shown to be a useful and promising tool, capable of revealing previous exposures to the virus.