Design and evaluation of Taqman low density array (TLDA) for monitoring post-transplant viral infections.

Cleland, Alexander; Malloy, Kristen; Donnelly, Mhairi C; Davidson, Janice; Simpson, Kenneth J; Petrik, Juraj

BACKGROUND The majority of transplant recipients undergo immunosuppressive treatment to prevent organ or tissue rejection. Consequently, they are more susceptible to infection agents including a number of viruses causing a significant morbidity and mortality. Only a limited number of viruses are currently tested for in transplant donors and recipients due to the cost and complexity. TLDA may provide a suitable format to address more systematic testing approach. METHODS 101 liver transplant recipient samples were retrospectively tested for 48 viral targets including two controls (BVDV and MS2) and two common viruses (TTV and HPgV), using a custom designed TLDA. 8 samples were analysed simultaneously on 384-well TLDA. Samples giving a signal considered positive/indeterminant were re-tested by different individual confirmatory assays. RESULTS Infections with six previously untested for viruses - EBV, HPIV3, HuPuV9, KIV, HMPV and HPV - were detected in fourteen patients. Previously detected HCV infections were also confirmed. These infections did not seem have an effect on 5 year post-transplant outcome. 55 of 79 and 17 of 87 samples available for confirmatory assays were positive for TTV and HPgV, included for the evaluation of the TLDA performance. CONCLUSIONS The custom viral TLDA can be successfully used for simultaneous detection of a range of post-transplant viral infections. To fully exploit its potential for monitoring and intervention, a whole blood testing should be applied in a prospective setting.