Your missing the point though XRAY
All we can do is point you in the right direction.
In a normal Photopost Integration what I said would work since that cell uses the medium and tddetail classes both of which do not specify an actual font type. The font type defaults to the body font type which is what I posted.
However if your using 4.8 and using some sort of style integration this can be different and will coincide with your specific tag that it uses in each style type. As Michael posted only you are going to know this. You can look right at the source of your page and find the span tag that surrounds the comment.