In 1992 Paul Plotz from NIH published a larger series and found nothing. Hilton from the Frenchay Hospital confirmed that in 1994. They noted non-specific binding of probes to inflammatory cells, which might well explain the earlier findings. Nothing positive since has been reported as far as I know.
Thanks, I was not aware that there were negative studies, nor the issue of non-specific binding. The Plotz 1992 study appears to be this one:
https://www.ncbi.nlm.nih.gov/pubmed/1349938
I also just found two further negative studies from 1993 and 1994:
https://ard.bmj.com/content/52/8/575
https://www.sciencedirect.com/science/article/pii/0022510X94902445
I can't seem to find any more recent positive studies, so perhaps those negative results are currently the last word.
However, I wonder if the PCR primers used in these negative studies might be an issue.
Since the landmark Chapman et al 2005 study on enterovirus in chronic myocarditis, it's known that the defective enteroviruses which cause persistent infections in myocarditis have small deletions in the 5′ end of their genome (ranging from 7 to 49 nucleotides in size).
Now I believe enterovirus PCR primers are usually designed to target the 5′ region because it's conserved; but since there are deletions in that region in persistent enterovirus, might it be possible that the primers in these negative studies were inadvertently targeting a deleted part of the genome, and thus got a (false) negative signal? I don't know enough about this subject to answer that.
But I know that Nora Chapman deliberately uses PCR primers to target the deleted part of the defective enterovirus genome, as a negative signal demonstrates the presence of enteroviruses with deletions.
I just spent the last two weeks researching and writing
an article on MEpedia about these defective deleted enteroviruses, so it's all at the forefront of my mind at the moment.