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

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. Taqman low density array (TLDA) may provide a suitable format to address more systematic testing approach. METHODS: One hundred and one liver transplant recipient samples were retrospectively tested for 48 viral targets including two controls (bovine viral diarrhea virus and MS2) and two common viruses (TTV and HPgV), using a custom designed TLDA. Eight 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.

Polymers for the cell-specific immobilisation of megakaryocytic cell lines.

Primary human megakaryocytes, the precursor cells of platelets, are difficult to collect and cultivate. Polymers that enrich these cells without affecting their regulation or function are of interest for basic research as well as for cord blood transplantation purposes since co-transplantation of enriched megakaryocyte concentrates increase the success of stem cell therapy. Herein, polymer microarrays were used for the discovery of substrates for MEG-01 cells, with five polymers identified which selectively bound cells of the megakaryocytic lineage. Flow cytometry and miRNA profiling revealed that immobilisation had only a minor effect on the cellular maturation status, making the identified substrates potential candidates for concentrating megakaryocytes from patients prior to transplantation.

Evaluation of the Roche cobas s 201 system and cobas TaqScreen multiplex test for blood screening: a European multicenter study.

BACKGROUND: The Roche cobas TaqScreen test, an automated, multiplex nucleic acid test for blood screening for hepatitis B virus (HBV) DNA, hepatitis C virus (HCV) RNA, human immunodeficiency virus type 1 (HIV-1) groups M and O, and HIV-2 RNA, on the cobas s 201 platform, was evaluated by six European blood screening laboratories. STUDY DESIGN AND METHODS: The 95 percent limit of detection (LOD) of the cobas TaqScreen test for HBV, HCV, and HIV-1, using dilutions of the WHO International Standards, were evaluated. The clinical performance was determined by testing between 2000 to 6000 routine donor samples. Some laboratories evaluated the robustness, cross-contamination, and workflow. RESULTS: The mean 95 percent LOD (95% lower and upper confidence intervals) for HBV, HCV, and HIV-1 across all the laboratories were 3.8 (range, 3.0-5.2), 10.8 (range, 8.4-14.4), and 56.7 (range, 43.0-79.2) IU/mL, respectively. A total of 23,716 donors were tested in pools of 6. Fourteen initially reactive pools were detected, of which 6 contained a reactive donation, giving a positive predictive value of the pool results of 43 percent. One of the reactive donations was a HBV yield case (hepatitis B surface antigen-negative/anti-HBc-positive). Evaluation of the workflow for the system showed that an optimized batch loading in which a pipettor (Hamilton Microlab Star IVD) was utilized to half capacity was better than a full batch loading. CONCLUSION: The 95 percent LOD for the three viruses were comparable to those obtained by Roche. The test and platform were shown to be sensitive, specific, flexible, and robust.