A simplified spot method for determination in serum of hepatitis B virus DNA (HBV DNA) by molecular hybridization is proposed. For simultaneous testing of 30 serum samples, it reduced to about 1 hr the duration of the steps preceding hybridization proper. The method also greatly reduced the loss of DNA during these steps and allowed more sensitive detection in samples of only 25 or 50 pl.
HBV DNA was determined in 181 serum samples by this method, and the results were pooled with 67 previous determinations by the Southern blot technique. Results for the pool were then compared to those obtained with radioimmunoassay for serological HBV markers.
Ninety-six of the 248 samples were HBV DNA positive. Eleven others gave variable or inconclusive results, probably due to low viral particle titers.
Seventy-two HBsAg-and HBeAg-positive sera contained HBV DNA, confirming that HBeAg is a marker of active viral replication. Fourteen other HBsAgand HBeAg-positive sera, obtained from eight patients, were either HBV DNA negative or oscillated between negative and positive, or, again, were weakly positive; serological follow-up in 7 patients showed seroconversion to anti-HBe in 5 , 3 of which became HBsAg negative. Eight of the HBsAg-positive sera were negative or borderline for HBeAg but contained HBV DNA and may, therefore, have been infective; seven of these sera had anti-HBe. Six HBsAg-negative sera contained HBV DNA and may also have been infective; five of these exhibited HBV antibodies.
These results indicate that molecular hybridization not only provides a more sensitive and direct method for detecting hepatitis B virus in serum but also defines additional serological patterns with predictive or epidemiological value.
Molecular hybridization is a powerful tool for detecting complementary nucleic acid sequences. We have already used this technique to determine the presence of hepatitis B virus DNA (HBV DNA) in the liver and serum of patients with liver diseases. In this previous study, we used the Southern blot method (1) for both liver and