Citocinas séricas da resposta imune em adultos e neonatos na imunidade treinada induzida por BCG : revisão sistemática

Abstract

The response of trained immunity occurs with low specificity, in a secondary infection, promoting a marked response of innate immune cells. This process comes from the stimulation of innate immunity through particles derived from infectious or non-infectious agents. The BCG vaccine is considered a potent inducer of innate immune memory. Its heterologous effects are being evaluated in different microorganisms, such as: viruses, bacteria, fungi and parasites. It is possible to evaluate the training of innate immune cells, after stimulation, using laboratory methods, and one of them is the dosage of cytokines. Cytokines are mediators of the inflammatory response, acting both in inducing the inflammatory process and in controlling and healing the injured tissue. The objective of this review was to evaluate the main cytokines characterized after the induction of immunity trained by the BCG vaccine, in healthy adults and neonates, and to verify if the results found in these two groups present similarities or divergences in the cytokines. This is a systematic literature review, using the NCBI databases (PubMed platform) and the Capes Periodicals to search and select articles. At the end of the search, selection and analysis, 10 articles were found. The results showed that there are no major differences between the findings of cytokines measured in adults and neonates, after induction of trained immunity by the BCG vaccine. These results suggest that trained immunity occurs at any age. Two of the selected studies addressed the results of cytokines measured after one year, demonstrating the permanence of BCG-induced trained immunity in this period. IL-6, IL-1β, TNF-α were the cytokines that stood out the most, as they demonstrated high serum levels in most studies. Pro-inflammatory cytokines are the ones that most change after induction of trained immunity. More long-term studies are needed to better understand trained immunity, which would benefit the advancement of new vaccines aimed at human protection against different types of infections by microorganisms. Vaccination with the BCG vaccine is safe, effective and approved, but its use to protect against other pathogens is still being studied