<正> The appearance of HBV DNA in the liver and serum of 15 patients with hepatitisB conifected with HDV was observed and compared with that of 13 HDV-negative cases.Itwas found that HBsAg titer was lower than or equal to 1:4 in 8 HDV-positive patients

inwhom it was temporally negative in 5

and negative during the

two-day hospitalization in 1.No similar result could be observed in the HDV-negative cases.The detection rate of HBVDNA in both the HDV positive and negative groups was 20.0％ （3/15） and 25％ （3.12） in se-rum

and 46.7％ （7/15） and 61.5％ （8/13） in the liver rcspectively.There was no signif-icant statistical difference between the 2 groups.The HBV DNA grains detected with in situ hybridization

with biotinylated HBV DNAprobe were demonstrated in the sparse type of distribution in 3 cases and lightly stained in 2.Itis believed that HBV DNA replication activity might be suppressed by HDV.However activeHRV DNA replication was also present in some HDV-positive patients and HBV DNA was posi-tive in both the liver and serum in 3 such patients.It was concluded that the difference of the detection rate of HBV DNA in HDV-positivepatients might be related to the different stages of HDV infection.