Application of real time PCR in post transplant monitoring of cytomegalovirus infection: comparison with other diagnostic approaches.

Immunosuppressive status in solid organ transplant recipients is often related to the reactivation of Human Cytomegalovirus (HCMV) infection that remains one of the major causes of morbidity and mortality. Therefore, the early detection of HCMV followed by infection monitoring is important to institute prompt and appropriate treatment. In recent years good results have been obtained by HCMV DNA amplification methods; qualitative and quantitative approaches have shown good sensitivity and specificity, but they often require post-PCR manipulation that adds time to the analysis and may lead to contamination problems. Recently, Real Time PCR (RT-PCR) has been proposed in HCMV DNA analysis as a valid method for its good sensitivity and rapidity. In the present study, twenty-five solid organ transplant recipients were analyzed for HCMV diagnosis; 60 peripheral blood leukocytes and 120 plasma samples were tested by RT-PCR and the results compared to those obtained by a qualitative Nested PCR and a quantitative DNA enzyme immunoassay.

Early evidence of lymphoproliferative disorder: post-transplant monitoring of Epstein-Barr infection in adult and pediatric patients.

Transplant patients are at high risk of post-transplant lymphoproliferative disorder (PTLD). A strong correlation between Epstein-Barr virus (EBV) and PTLD is observed in pediatric patients with primary infection after transplant. Because many patients have responded to reversal of immunosuppressive therapy, an early identification of EBV is essential for the reduction of immunosuppression and/or introduction of antiviral therapy to prevent PTLD. Polymerase chain reaction (PCR) is a specific and sensitive method to identify EBV DNA in blood. The aim of our study was to establish a protocol for monitoring EBV infection in transplanted patients for early identification those at high risk of PTLD. Viral presence in peripheral blood leukocytes (PBL) and serum samples was revealed by Nested PCR; positive specimens were quantified with Real Time PCR (RT-PCR). DNA in PBL was observed in 12 cases and 6 showed EBV in sera. Quantitative analysis showed a wide range of EBV DNA copies in leukocytes that were higher than in sera. Two patients displayed high viral load values in both PBL and sera associated with clinical evidence of PTLD. Our data suggest that the study of the EBV load represents an essential approach in the diagnosis of PTLD and the analysis of serum samples could provide useful information in the post-transplant monitoring of high-risk patients.