Investigation of HGV and TTV infection in sera and saliva from non-hepatitis patients with oral diseases

Abstract

Aim: To determine the frequencies of HGV and TTV infections in serum and saliva samples of non-hepatitis patients with oral diseases in Hangzhou area, and to understand the correlation between detected results of HGV RNA and/or TTV DNA in sera and in saliva from the same patients.

Methods: RT-nested PCR for HGV RNA detection and semi-nested PCR for TTV DNA detection were performed in the serum and saliva samples from 226 non-hepatitis patients with oral diseases, and nucleotide sequence analysis.

Results: Twenty-seven (11.9 %) and 21 (9.3 %) of the 226 serum samples were only positive for HGV RNA and TTV DNA, respectively. 10 (4.4 %) and 9 (3.9 %) of the 226 saliva samples were only positive for HGV RNA and TTV DNA, respectively. And 7 (3.1 %) of the serum samples and 2 (0.9 %) of the saliva samples showed the positive amplification results for both HGV RNA and TTV DNA. 12 saliva samples from the 34 patients (35.3 %) with HGV or HGV/TTV viremia and 11 saliva samples from the 28 patients (39.3 %) with TTV or HGV/TTV viremia were HGV RNA detectable, respectively, including two patients positive for both HGV RNA and TTV DNA in serum and saliva samples. No saliva samples from the 226 patients were found to be HGV RNA or TTV DNA detectable while their serum samples were negative for HGV or TTV. Homologies of the nucleotide sequences of HGV and TTV amplification products from the serum and saliva samples of the two patients compared with the reported sequences were 88.65-91.49 % and 65.32-66.67 %, respectively. In comparison with the nucleotide sequences of amplification products between serum and from saliva sample from any one of the two patients, the homologies were 98.58 % and 99.29 % for HGV, and were 98.65 % and 98.20 % for TTV, respectively.

Conclusion: Relatively high carrying rates of HGV and/or TTV in the sera of non-hepatitis patients with oral diseases in Hangzhou area are demonstrated. Parts of the carriers are HGV and/or TTV positive in their saliva. The results of this study indicate that dentists may be one of the populations with high risk for HGV and/or TTV infection, and by way of saliva HGV and TTV may be transmitted among individuals.

Figure 1

Target fragments respectively amplified from HGV RNA and TTV DNA in serum and saliva samples. (1: HGV negative serum sample; 2 and 3: HGV positive serum sample and saliva sample (No.: 010906); 4: blank control for HGV detection; 5: TTV negative serum sample; 6 and 7: TTV positive serum sample and saliva sample (No.: 011022); 8: blank control for TTV detection; 9: marker)

Figure 2

Homology of the nucleotide sequences from HGV RT-nested PCR products of the 2 serum and 2 saliva samples from 2 patients compared with the reported sequence. (1: The reported HGV sequence[14]; 2 and 3: the sequences of HGV RT-nested PCR products from the serum sample and saliva sample from the patient (No.: 010906); 4 and 5: the sequences of HGV RT-nested PCR products from the serum sample and saliva sample from the patient (No.: 011022). Underlined areas indicate the primer positions.

Figure 3

Homology of the nucleotide sequences from TTV semi-nested PCR products of the 2 serum and 2 saliva samples from 2 patients compared with the reported sequence. (1: The reported TTV sequence[57]; 2 and 3: the sequences of TTV semi-nested PCR products from the serum sample and saliva sample from the patient (No.: 010906); 4 and 5: the sequences of TTV semi-nested PCR products from the serum sample and saliva sample from the patient (No.: 011022). Underlined areas indicate the primer positions.