Comparação entre a Técnica de Captura do Híbrido e a Reação em Cadeia da Polimerase na Detecção de Infecções Causadas por Papilomavírus Humanos no Colo do Útero

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The Human Papillomavirus (HPV) infections are the most frequent Sexually Transmitted Diseases worldwide. Nearly 30% of these infections are persistent, fact associated with a significant increase in risk for cervical neoplasia. Thus, the screening of persistent infections, associated with high-risk HPV types, would result in prevention of the cancer. For this reason, there is a search for which is the best technique of detection of HPV infection and patient screening. In order to contribute for this study, our research compared the techniques of Hybrid Capture Assay and Polimerase Chain Reaction, both used in the diagnosis of HPV infection. For that, 1616 samples of female patients had been studied. They were attended at Laboratorio Sergio Franco, during year 2001. For the Hybrid Capture Assay the kit Digene Hybrid Capture II was used (HCAII), where the HPV types are separated in: group A (low-risk) and group B (highrisk), and for the PCR, we used generic primers MY09/11, and specific primers for the E6 gene of high-risk HPV types (HPV 16,18,31,33,35) and E7 (HPV 58). Of all 1616 samples, 745 (46,1%) were positive for some HPV type. And the most part (91,4%) presented high risk HPV infection alone or with one low-risk HPV type, characterizing a population with high risk to develop cancer. The age average of the patients was 30 years, what also agreed with the age band of most part of infected women in our study. Within the 1616 samples, we selected 97 for PCR analysis, if the patient presented the citopathological diagnosis from the same period. The PCR detected HPV DNA in 79 patients, while in HCAII we found 68 positive samples. The most prevalent HPV type detected by the PCR was the HPV16 (48%), followed of HPV18 (40%), HPV35 (8%),31 (4%) while HPV 33 and 58 had not been detected in this samples. Our data pointed that PCR had the highest sensitivity, as described in literature. Both PCR and HCAII showed good agreement with the results from Citopathology: the increase of severity of Pap diagnosis corresponded to an increase in HPV detection by PCR and HCAII. The general agreement between HCAII and PCR was 78.4%. However, in the cases of Inflammatory Alterations, the PCR was more efficient than the HCAII; the positivity for the PCR was of 78,8% and for the HCAII it was of 48,8%, justified by either false-positive or false-negative results, related to both techniques. The viral load obtained by HCAII showed an upward trend from normal to LSIL with a fall in HSIL. But measures were generally inconclusive, with statistic significant values restricted to LSIL. Considering the high costs of these techniques, the implications in the prevention and the treatment of HPV infections, we conclude that both HCAII and PCR can be used to complement the Citopathology (Papanicolau), that is used to screening HPV in the general population. This would result in effective prevention against the cervical cancer, mainly, in women above of 35 years old, since this age group may represent the one with persistent HPV infections, that constitute the main risk factor for carcinogenesis.

ASSUNTO(S)

patologia experimental câncer cervical pcr papilomavirus humanos reação em cadeia da polimerase microbiologia lesões cervicais captura do hibrido colo uterino

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