Grupo interdisciplinar de pesquisa em HTLV-1 e 2: Pesquisa do vírus HTLV-1 em biópsias de pele de indivíduos soropositivos: aspectos ultraestruturais e moleculares

Abstract

The virus HTLV-1 can be considered an emerging virus if we take into account that each day new viral isolates are characterized. For example, groups e and f, in Central Africa, characterized by SALEMI et al. (1998) and supported by phylogenetic analysis, showed they have evolved through interspecies transmissions among humans and apes occurring since ancient times and that may still be occurring. Of 10 to 20 million people are infected around the world and aspects of virus-host interaction, as well as the molecular characterization of viral isolates of endemic regions, are of paramount importance for the study of epidemiology and forms of control, prevention and treatment of this virus. The viral isolates objects in this work were obtained from skin biopsies of seropositive individuals for HTLV-1 and with dermatological manifestation of chronic disease. After extraction of genomic DNA from skin biopsies of these individuals was made the PCR "nested" of part of the HTLV-1 env gene. Of skin biopsies, 90% gave positive PCR result, corroborating the serological test positive for HTLV-1 in these individuals. The main target of HTLV-1 is the CD4+ T lymphocyte, present in large proportion in inflammatory infiltrate, and that remains immortalized after being infected. The tax protein of HTLV-1 is responsible for transcription and induction of several cellular genes, such as cytokines, chemokines and adhesion molecules that are essential for dissemination and tissue localization of these lymphocytes. Transmission electron microscopies of these biopsies were performed in order to verify the presence of preliminarily HTLV-1, and observe the ultrastructural morphology of inflammatory infiltrate cells and tissue location. Mononuclear cells were found infiltrating the dermal papillae and peri-vascular regions, having been observed migration of these cells to the epidermis. They presented a convoluted nucleus, indentation, with evident nucleoli and increased cytoplasmic extensions. It was also observed the presence of vacuoles in some cells. The cell lysis was almost absent. Structures with a diameter ranging from 100 nm to 400 nm and ultrastructural characteristics of particle of HTLV-1, were observed near or springing from the cytoplasmic membrane of cells with ultrastructural lymphoid series and fibroblasts morphologic characteristics. An umbilical cord cell line transformed by the HTLV-1, MT-2, was used as positive control techniques performed. As negative control were obtained fragments of normal skin from individual subjected to breast reconstructive plastic surgery. The findings of this study support the hypothesis that the skin is one of the target organs of HTLV-1. This virus keeps multiplying in magazines of the skin and causing a chronic inflammatory reaction site in infected individuals, whose purpose is to attempt to control the infection. According to global data there is a risk of 1% to 5% of infected individuals develop any disease associated with HTLV-1, of 40 to 50 years after infection. As in our middle age of this commitment has been minor, it becomes necessary to the molecular characterization of these viral isolates aiming at a better understanding of the epidemiology of HTLV-1 in our midst. After the cloning and sequencing of amplified segment of part of the HTLV-1 env gene, and subsequent phylogenetic analysis, the results obtained have shown that the viral isolates analyzed pertain to the Cosmopolitan group a, transcontinental sub-group A, which is a genotype of higher prevalence and distribution in Brazil and in the world. This research is part of a cross-sectional study of open cohort of individuals HEMOMINAS Foundation of Belo Horizonte, with positive serology for HTLV-1, which already has more than 500 individuals registered and accompanied at two- year intervals. So is inserted within a larger project developed by the GIPH, Interdisciplinary Group of Research in HTLV-1 and 2, of which I am part, and involves various professionals from various areas and various research institutions such as the HEMOMINAS Foundation of Belo Horizonte, the UFMG and the Sara Kubitschek Hospital. The results of this study will be of immense value to know better the manifestations of HTLV-1 in skin of the carriers of HTLV-1 in our midst. In this way, we can perform a control and more efficient treatment of related diseases.