Rapid quantification of hepatitis B virus DNA by real-time PCR using efficient TaqMan probe and extraction of virus DNA.

AIM: To rapidly quantify hepatitis B virus (HBV) DNA by real-time PCR using efficient TaqMan probe and extraction methods of virus DNA. METHODS: Three standards were prepared by cloning PCR products which targeted S, C and X region of HBV genome into pGEM-T vector respectively. A pair of primers and matched TaqMan probe were selected by comparing the copy number and the Ct values of HBV serum samples derived from the three different standard curves using certain serum DNA. Then the efficiency of six HBV DNA extraction methods including guanidinium isothiocyanate, proteinase K, NaI, NaOH lysis, alkaline lysis and simple boiling was analyzed in sample A, B and C by real-time PCR. Meanwhile, 8 clinical HBV serum samples were quantified. RESULTS: The copy number of the same HBV serum sample originated from the standard curve of S, C and X regions was 5.7 multiply 10(4)/mL, 6.3 multiply 10(2)/mL and 1.6 multiply 10(3)/mL respectively. The relative Ct value was 26.6, 31.8 and 29.5 respectively. Therefore, primers and matched probe from S region were chosen for further optimization of six extraction methods. The copy number of HBV serum samples A, B and C was 3.49 multiply 10(9)/mL, 2.08 multiply 10(6)/mL and 4.40 multiply 10(7)/mL respectively, the relative Ct value was 19.9, 30 and 26.2 in the method of NaOH lysis, which was the efficientest among six methods. Simple boiling showed a slightly lower efficiency than NaOH lysis. Guanidinium isothiocyanate, proteinase K and NaI displayed that the copy number of HBV serum sample A, B and C was around 10(5)/mL, meanwhile the Ct value was about 30. Alkaline failed to quantify the copy number of three HBV serum samples. Standard deviation (SD) and coefficient variation (CV) were very low in all 8 clinical HBV serum samples, showing that quantification of HBV DNA in triplicate was reliable and accurate. CONCLUSION: Real-time PCR based on optimized primers and TaqMan probe from S region in combination with NaOH lysis is a simple, rapid and accurate method for quantification of HBV serum DNA.

[A clinical study on CD178 positive T lymphocyte in hemorrhagic fever with renal syndrome].

BACKGROUND: To further probe into the role of CD178 in the pathogenesis of hemorrhagic fever with renal syndrome (HFRS). METHODS: The expression of CD178 and HLA-DR on T cell subsets in peripheral blood of patients with HFRS and their dynamic changes were detected by Flow cytometry. RESULTS: CD4+ CD178+ and CD8+ CD178+ T lymphocytes both in fever and polyuria phases were significantly higher than those in normal controls, while there was no significant difference between the both phases of HFRS (P > 0.05). CD178 expression on CD4+ HLA-DR+ and CD8+ HLA-DR+ T lymphocytes were significantly higher than those in normal controls (P < 0.05, P < 0.01, P < 0.001, P < 0.001), while there was no significant difference between CD4+ HLA-DR+ and CD8+ HLA-DR+ T lymphocytes (P > 0.05). CONCLUSION: CD178 was expressed on both CD4+ and CD8+ T cell subsets, but mainly on CD8+ T cell subsets both in early stage and in later stage in the pathogenesis of HFRS. Cytotoxic T lymphocyte (CTL) might kill target cells infected by hantavirus (HV) and eliminate HV via cell apoptosis mediated by CD178 in early stage of HFRS. In later stage of HFRS, CD178 might reduce antigen-specific T lymphocytes by activation induced cell death (AICD) and help to maintain the homeostasis of immune system.