Quantitative Analysis of CMV-DNA Load in Renal Transplant Recipients Using Real-Time PCR

rimary infection with CMV is controlled in individuals with normal immune system, but when immune suppression occurs, CMV can reactivate and grow to high titer. The ability of CMV to remain latent after infection, contributes a great deal to serious CMV diseases (1). After transplantation the severe immunosuppressive regimes use to prevent rejection of the transplant, make the recipients prone to severe CMV disease. Infection with cytomegalovirus (CMV) is a significant cause of morbidity and mortality in renal transplant recipients, (up to 60% of primary infection) (2). The detection of CMVDNA in plasma suggests active viral replication and spread of the virus from the leukocyte into the plasma (3). Viremia is only marker of active CMV infection. The ability to amplify CMV-DNA by PCR (qualitative and quantitative) has become a valuable diagnostic tool for detection of CMV in the early stages of infection prior to the disease (4). Although antigenemia is the gold standard in diagnosis and monitoring of infection, there is concern that some infections with low level of viral load that cannot be detected by antigenemia. 5 There is a variation in viral load results among different in house-developed CMV PCR quantitative (qn) assays (6). Therefore, we need to use a standard assay to reduce the variation in viral load results. The aim of this study was to investigate CMVDNA viral load in active CMV infected renal transplant patients using LC Real -Time CMV PCR technique (Roche system, version 2). In this cross sectional study, we investigated CMV DNA viral load in 30 active CMV infected renal transplant recipients (15 females and 15 male and mean age 42.9 years), who referred to Iranian Blood Transfusion Organization (IBTO) research center during 2008 to2009. A written informed consent was taken from renal transplant recipients prior to enrolment into the study. We used plasma negative sample and internal control to prevent false positive results and to control DNA extraction procedure in each qn and ql PCR run. Viral DNA was extracted from 0.2ml plasma by using of QiAamp DNA blood mini kit (Qiagen, Germany) and RealTime PCR (q RT-PCR) was performed by Artus CMV LC PCR kit based on manufacture (5) instruction. This kit is designed on the basis of specific prob. The correlation between the number of antigen-positive cells and level of CMV-DNA in plasma was analyzed by Pearson correlation test. The average of CMV DNA viral load was 7.61× 10 7 copies/ml (min. load: 1.38×10 2