14745
None of 33 PBMC specimens from healthy adults and only one of 40 pediatric samples was positive (at a low level) for adenovirus DNA by nested PCR assay .
 ( DNA: adenovirus DNA, None) , ( cell type: PBMC, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( DNA: adenovirus DNA, None) , ( cell type: PBMC, None) 