Avaliação da sensibilidade à bleomicina em pacientes cronicamente infectados pelo vírus da hepatite B

Abstract

The bleomicyn sensitivity test in lymphocytes has been used to investigate individual mutagen sensitivity and DNA repair capacity. Mutagen sensitivity is determined by individual genetic composition. However, it is assumed that it may be influenced by the chronic exposition to mutagens that could compromise components of the mechanisms of DNA repair. In this study, bleomycin sensitivity was measured by the micronucleus (MN) test in 29 chronically HBV-infected patients and 23 healthy controls. The basal frequency (‰) of MN was similar (p=0.09) in patients (19.55±10.6) and controls (15.04±7.4). Bleomycin increased the ‰ MN in cells of patients (71.10±23.6; p<0.0001) and controls (49.5±19.1; p<0.0001), but the increase was most substantial in patients (p=0.01). The net increase of ‰ MN induced by bleomycin was higher in cells of HBV-infected patients (p=0.005), independent of sex and age (R=0.41; p=0.03). Finally, when individuals were separated into bleomycin sensitive and non-sensitive (considering as cut-off point the 50th percentile of values of the net increase of ‰ MN), the percentage of HBV-infected patients was higher among sensitive individuals (65.5%) as compared with the non-sensitive group (34.5%). This was contrary to what was observed for the controls (30.4% sensitive, 69.6% non-sensitive) (p=0.01, OR= 4.3, IC= 1.3- 14.03). Therefore, our data suggest that the chronic infection by HBV increases bleomycin sensitivity. Considering the potential of mutagen sensitivity for detecting cancer-prone subjects, a prospective study with HBV-infected patients should be interesting.