Simultaneous Assessment of Plasma and Peripheral Mononuclear Cells for Multiple Viral Load Quantification in Peripheral Blood of Patients after Heart Transplantation

Abstract

Purpose Epstein-Barr Virus (EBV) is well known to be associated with posttransplant lymphoproliferative disorders (PTLD). Due to moderate immunosuppression in heart transplant (HTx) recipients, many viruses other than EBV are also infected and activated and assessment of simultaneous viral loads of other viruses is also important. In the present study, the role of simultaneous assessment of plasma and peripheral mononuclear cells for multiple viral load quantification in peripheral blood of pediatric patients after heart transplantation was elucidated. Methods In a period of 9 months (from January to October 2009) we collected 28 samples of 3 adult and 6 pediatric cardiac transplant recipients. Quantitative polymerase chain reaction for EBV, Cytomegalovirus, Parvovirus 19 (B19), BK and JC virus, and HHV6 was simultaneously performed based on the TaqMan system using DNA which isolated from peripheral mononuclear cells (PBMCs) and plasma, as described elsewhere. Phenotyping of infected lymphocytes were also done. CD8, CD19, CD45RO, CD57, etc. Results Case 1: 2-year old girl who underwent HTx at 1 year of her age, developed B cell type PTLD and died of cytokine release syndrome, showed rapid increases in EBV load in both PMBC and plasma as well as HHV 6 and B19. Case 2: 22-year female with subclinical infection for 19 years after HTx, showed sudden decrease in both in EBV load in both PMBC and plasma after conversion of everolimus to mycophenolate mofetil and both EBV loads eliminated after cytotoxic T lymphocyte (CTL) formation against EBV. Three patients (clinical in 2 and subclinical in 1) showed an increase in B19 load. Although B19 load became negative in 2 patients, B19 load sustained positive for 9 months in one patients who experienced B cell type PLTD 6 years ago and had continuous B19 infection. In one 38-year old male with steroid treatment for nephrosis and one 11-year old boy with living renal transplantation 10 years after HTx showed increases in BK and JC virus loads and an rapid decrease in both viral loads after reduction of immunosuppression. Conclusion Simultaneous multiple viral load quantifications are useful to evaluate immunosuppressive status of HTx recipients as well as monitoring of viral infection itself.