Análise epidemiológica, microbiológica e resposta imune periapical em pacientes HIV positivos e negativos portadores de infecções endodônticas

Abstract

Pulpo-periapical pathologies cover many areas of knowledge, including epidemiology, microbiology and immunology. Even though they have been widely investigated in humans and animals, there is a gap in knowledge regarding the role of the human acquired immunodeficiency syndrome on these pathologies. The present study evaluated the need for endodontic treatment in an HIV-positive population and assessed its correlation with systemic and personal data of those individuals. Subjects that needed endodontic treatment had the root canals of those teeth analyzed for their microbiological and immunological profile. HIV-negative individuals (that needed endodontic therapy) were selected as controls for comparison. We evaluated the presence of 107 microbial species by combining the Multiple Displacement Amplification (MDA) technique and the checkerboard DNA-DNA hybridization technique. Using Real Time PCR, we evaluated the gene expression of lymphocytes TCD4+CD28+ and TCD8+, cytokines and chemokines: TNF-, IL-1, IL-10, IL-17A, IFN-, CCL2, RANKL, CCL4, CCL5, CXCR4, and CCR5. Samples were collected at two times points, immediately after cleaning and shaping the root canal system and 7 days later. In the HIV-positive group, it was observed that the majority individuals were females, that 14% of the subjects needed endodontic treatment and that 79.2% of the HIV positive subjects were under the HAART regimen. There was a positive correlation between the need for endodontic treatment and a low CD4 + T-cells count. There were, in average, 22.6 (± 1.4) and 21.3 (± 2.0) species per root canal in HIV-and HIV + respectively (mean±SD). D. pneumosintes, H. pylori and S. constellatus were the most abundant bacterial species among HIV positive individuals. The geneexpression of TCD4 CD28 cells and TCD8 increased after the reduction of intracanal microbial content in both groups (HIV-positive and HIV-negative). It was observed that in HIV-negative individuals the local expression of pro-inflammatory mediators was downregulated after root canal instrumentation. Conversely, in HIV-positive individuals the expression of these mediators was upregulated in the same time point, which paralleled with an upregulation of IL-10 in HIV-negative and CXCR4 in HIV-positive individuals. It can be concluded that: a) despite the positive relationship between the need for endodontic treatment and low counts of CD4+ T cells, this phenomenon is probably due to a low adherence to HAART regimen, b) when comparing the root canal microbiota of HIV-positive and negative individuals it was observed that these infections are polymicrobial and include medically important bacterial species, which were commonly found in the SCR of HIV-positive subjects; c) the expression of TCD4+CD28+ and TCD8+ cell markers in both groups (HIV-positive and negative) seems to be affected by the presence of microbial stimuli inside SCR; d) the (local) gene expression of cytokines and chemokines showed that the pro-inflammatory response in HIV-positive occurs later, when compared to that observed in HIV-negative subjects.