Avaliação do perfil de subclasses de IgG como fator prognóstico de gravidade de dengue

• Autor(a) principal: Junqueira, Isabela Cinquini
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8371
• topic: Dengue; Subclasses IgG; Anticorpos; IgG subclasses; Antibodies; Dengue; SAUDE COLETIVA::EPIDEMIOLOGIA

Variations in IgG subclass concentrations are associated with numerous infectious diseases. Observations on dengue hemorrhagic fever pathogenesis suggest a high degree of immune stimulation with extensive activation of complement system preceding the onset of shock, signaling a possible role of complement activation products in endothelium damage and plasma leakage. Antibodies IgG1 and IgG3 are known to activate the complement system efficiently while IgG2 and IgG4 are weak activators. Moreover, these are the subclasses that exhibit cytophilic properties. Studies have demonstrated that antibodies in association with FcRs receptors, present on the surface of numerous cells of the organism, are involved with both, protection and dengue imunopathogenesis. In the present study, IgG subclass antibodies antigen-specific and also non DENV specific were determined in dengue seropositive patients through respectively semi-quantitative and quantitative enzyme immunoassays “in house” procedures. Serum samples of individuals participating in this study were collected in the epidemic period of october 2005 to march 2006 on dengue reference health care units in the city of Goiânia-GO. Study groups were divided as follows: 30 – dengue fever (DF); 30- dengue with complications (DCC) and 30- dengue hemorrhagic fever (DHF). Overall, it was observed an increase in total IgG1 and IgG3 in dengue more severe clinical forms, except in the age group of 25-45 years in which the highest concentration of IgG1 was observed in subjects with DF and not DCC nor DHF. As for antigen-specific subclasses, it was found an IgG1 raise and IgG3 decrease in the most severe clinical forms of the disease. It was also observed a significant difference in IgG1 and IgG3 concentration between the most severe clinical forms, DCC and DHF. DCC clinical form was characterized by a larger concentration of IgG3 DENV-specific while the clinical form of DHF was characterized by an increased amount of total and specific IgG1. The results of this study indicates that it may be a correlation between IgG subclasses concentrations, mainly IgG1 and IgG3, and dengue prognosis.