Análise da resposta imune inata e adaptativa em crianças de 2 a 6 anos de idade, com e sem episódios de infecções respiratórias recorrentes

Abstract

Justification: Immunological factors may be associated with increased susceptibility 387 to respiratory infections and the relative frequency of these transient and partial 388 deficiencies in childhood. Understanding the reaction and response capacity of the 389 immune system in its different compartments is important for a better understanding 390 of the mechanisms that are directly involved in the susceptibility to Recurrent 391 Respiratory Infections presented by children, until they reach their immunological 392 maturity. Objectives: To analyze the innate immune response through the production 393 of pro and anti-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-8 and IL-10 e), and to 394 analyze the humoral adaptive immune response through production of class and 395 subclasses of tetanus anti-toxin IgG antibodies in children aged 2 to 6 years, with and 396 without episodes of Recurrent Respiratory Infections. Material and methods: 397 Peripheral blood samples (5mL), obtained by venipuncture, were collected from 398 children between 2 and 6 years of age treated at the general pediatric outpatient clinic 399 of Universidade Federal Triângulo Mineiro (UFTM). Of the samples collected, 86 were 400 analyzed, of which 36 corresponded to the test group (children who had Recurrent 401 Respiratory Infections in the absence of underlying disease that justified them) and 402 50 to the control group (healthy children, with no history of Recurrent Respiratory 403 Infections), without clinical signs and symptoms suggestive of Chronic Diseases, and 404 those whose parents accepted to participate in the study, ready to answer a 405 questionnaire, containing information about obstetric, family, morbid, nutritional, 406 habits and life conditions and vaccination history of the child. kid. The mononuclear 407 cells were separated in Ficcol hipaque gradient and cultured for 24 hours in the 408 presence of Medium or LPS, and the cytokines, IL-1 β, TNF-α, IL-6, IL-8, and IL-10, 409 from the supernatants of culture, were analyzed using the Cytometric Bead Array - 410 CBA technique. Plasma was separated to analyze the levels of specific anti-Tetanus 411 Toxin antibodies (total IgG and subclasses IgG1, IgG2, IgG3), by the indirect ELISA 412 technique. Results: The results showed that children with Recurrent Respiratory 413 Infections and children in the control group, have similar capacity to respond to 414 cytokines induced by LPS, as well as to produce antibodies to T-dependent antigen. 415 Within the various mediators of the immune response analyzed, the lower production 416 of IL-1β, in unstimulated cultures, called the attention of the group of children with 417 Recurrent Respiratory Infections. Conclusion: The lower production of IL-1β, in 418 unstimulated cultures, by the group of children with Recurrent Respiratory Infections 419 suggests that this group may have a lower baseline activation, and that this may be 420 influencing their capacity and speed of response.