[Quantitative analysis of human herpes virus type 8 and expression of its genes in patients with multiple myeloma]

To investigate if infection of human herpesvirus type 8 (HHV8) exists in Chinese patients with multiple myeloma (MM), and to identify the relationship between clinical manifestation and the viral load in bone marrow biopsy samples.

Real-time quantitative PCR was conducted to define the viral load of HHV8 in bone marrow biopsy samples from 23 patients with MM. Nested PCR was conducted to amplify the KS330(233)Bam fragment of HHV8 from peripheral blood mononuclear cells, bone marrow aspirates and bone marrow biopsy samples. RT-PCR was used to study the expression of suspected oncogenes: vIL-6 and vIRF-1 genes. Bone marrow biopsy samples of 5 patients with blood diseases other than MM and 5 patients with non-blood system diseases were used as controls. PCR product of BCBL-1 cell line was used as positive control.

(1) The positive rate of HHV8 in bone marrow biopsy samples from patients with MM was 69.6% (16/23) by real-time fluorescence quantitative PCR, and 82.6% (19/23) by nested-PCR. 16 bone marrow samples positive by fluorescence quantitative were positive too by nested-PCR. However, 3 bone marrow samples positive by nested-PCR were negative by fluorescence quantative. HHV8 was positive in only one of the 25 bone marrow aspirates from patients with MM (4%) and in none of the 20 peripharal blood samples from patients with MM. PCR showed negative result in 7 bone marrow aspirates taken form 13 MM patients with positive result by fluorescence quantative PCR. HHV8 was negative in bone marrow biopsy samples from patients with other diseases. HHV8 was negative in the peripheral blood samples from 16 MM patients, among which 9 out of the 11 cases with bone marrow biopsy samples taken showed HHV8 positive by fluorescence quatative PCR. Bone marrow biopsy samples of all patients with other blood diseases and non-blood system diseases were HHV8 negative. RT-PCR showed that among 12 MM patients the expression rate of vIRF-1 was 83.3% (10/12), and expression rate of vIL-6 was 0. The PCR positive products tallied with the sequence of HHV8 DNA. Clinical analysis showed that all of the patients with negative results had had chemotherapy.

There is a certain association between multiple myeloma pathogenesis and HHV8. In detection of HHVb, nested-PCR is more sensitive than fluorescence quantitaative PCR. The viral gene vILR-1 plays a certain role in the pathogenesis of MM.