Epstein-barr Virus And Human T Cell Leukemia Virus And Mycosis Fungoides Pathogenesis Of Research

Objective: Cutaneous T-cell lymphoma is a non-Hodgkin lymphoma, thepathogenesis remains unknown. It consists of Sezary syndrome, MF-related follicular mucinosis, eczematoid carcinoma reticulosis granunulomatous slack skin, primary cutaneous large T-cell lymphoma, primary cutaneous CD30 positive large cell lymphoma, subcutaneous panniculitis-like T-cell lymphoma and so on. Recently some studies suggested that retrovirus and herpes virus might play an improtant role in the pathogenesis of CTCL. But there are only few literature refered to the correlation between EB virus and primary cutaneous T-cell lymphoma and the conclusions were controversial. Some investigators detected DNA of EB virus or other abnormal gene positive in PBMNC of CTCL, while others got opposite findings. Mycosis fungoides are also called mycosis disease. It is a primary low-grade cutaneous peripheral helper T-cell lymphoma. Histophathology revealed that there were abundant lymphoma cells in the epidermis. It is a major subtype of CTCL. The incidence of MF in the Uuited States and Japan are higher than that of China. But there is an increasing trend. The course of the disease may last more than thirty years. MF has a history of 190 years. Numerous studies have been conducted, but the etiology has not been clear. However recent observations suggest that virus infection, oncogene, cytokine, occupational and environmental factors may be involved. The interaction of viral infection, host susceptiblility and immune cells, and persistant antigen stimulation may potentially causity in the development of MF. Recent observations revealed an important role of EBV in the pathogenesis of MF. An increasing body of data on on the correlation between MF and viral infection hasbeen acuumulated, but consensus has not been reached.EBV is a human lymphotrophic Y -DNA herpes virus., also refered to as herpesvirus type 4. It has two subtypes: I and II. In 1964, Dr. Epstein Barr firstestablished two lymphoma cell lines from Burkitt lymphoma. The electron-microscopic morphology of EB virus are similar to.other herpes viruses. The virus infects both lymphocytes and epithelial cells. It causes several clinical syndromes, such as infectious mononucleosis and B cell and nasopharyneal carcinoma. It had been previoulsy considered that EBV were only involved in the development of B-cell lymphoma, but more recently increasing evidences suggested that T-cell lymphoma is also related to EBV, while the exact mechanism is still unknown. Now it is clear that LMP-1 and BARF-1 are the virus oncogenes of EBV. LMP-1 is important for B lymphocyte immortalization, while LMP-1 can transform 3T3 cells in vitro, and form tumor in nude mice. In 1988, EBV-DNA was first detected in T-cell lymphoma with molecular-biology technique. After that, it has been confrimed by several recent studies that EBV positive T-cell lymphoma is far more than EBV positive B cell lymphoma in NHL except Burkitt lymphoma. The EBV detection rate of T-cell NHL is 63.6%. About 10% T-cell lymphoma is EBV related, and this subpopulation is more prevalent in Asia.How EBV infects T lymphocytes has not been made clear. Some studies suggested that T cells express EBV/c3d receptor (CD21) in their certain developmental stages, so EBV may infect T cells directly binding to c3d receptor. Studied found that it is difficult to infect normal T cells Ex vivo with EBV to establish immortalized cell lines and in vivo infection of normal T cells by the virus can hardly occur. All mentioned above implicate that T cell and B cell infection by EBV and the fate of EBV after infection may be defferent ,and the viral infection may exert various impacts on the host. T cell is the recepient of EBV. The DNA of EBV maintains linear molecular structure and self-circling does not occur inside T cell. The low circling of viral DNA in T cell results in low transformation of T cell induced by the virus. This indicates a possible pathogenesis of T-cell lymphoma induced by EBV and T cell proliferation.The EBV polymerase accessory protein, BMRF1, is an essential component ofthe viral DNA polymerase and is required for lytic EBV replication. It is a specific CTL epitope of EBV antigen. The sequ ence is 268-276. It is HLA restricted. The EBV specificity of BMRF1 is undertermined. The study by Qin demonstrated that BMRF1 is a trransactivator, inducing expression of the essential oriLyt promotor, BHLF1. Replication from oriLyt requires the products of six viral genes: BALF1, BMRF1, BSLF1, BBLF1 and BBLF2/3. The BMRF1 gene product is the major early phosphopotein induced druin EBV lytic replication and is a double-stranded DNA-binding protein that is essential for processive DNA synthesis by the viralpolymerase.Our study aimed to determine whether there were infection and replication ofEBV in MF patients, so to investigate the relationship of EBV infection and the onset of MF. We detected the expression of EBV DNA and BMRF1 gene from the peripheral blood mononuclear cells of seven MF patients with polymerase chin reaction.Method: To detect EBV DNA in PBMC of seven MFs and five normal controls. Amplify EBV BMRF1 gene in PBMC from EBV positive samples, using EBV cell line as positive control and deionized water as negative control. The specific primer sequences for EBV DNA amplification are as following: 5' -CCAGACAGCAGCCAATTGTC-31 and 5-GGTAGAAGACCCCCTCTTAC-3', which located in BamH-I-W region. The amplified product is 129bp. The specific primer sequences for EBV BMRF1 gene amplification are followed: 5'-CAGGCTTCCCTGCAATTTTA-CAAGCGC-3\ and5'-CCCAGAAGTATACGTGGTGACGTAGA-3\ The size of amplification product is 288bp. Electrophoresed in 1.5% agarose gel and stained with ethidium bromide, the PCR products band were visualized with an ultraviolet transilluminatior. Results: 1. Detection of EBV DNA in PBMCAfter amplify the extracted DNA of PBMC of MF patients using EBV DNA specific primers, the electrophoresis in 1% agarose gel showed that 2/7 MF samples were positive. Two clear electrophoresis bands were seen around 129bp, 5/7 samples were negative. The positive rate was 28.5%. For the two positive samples, one was in plaque stage and the other in tumor stage. The PCR products of five normal samples were all negative.