ncis - Did McGee and Abby ever get into a relationship?

In season two of NCIS, there seems to be a "thing" between Abby and McGee although this is never specifically stated.

In the season two episode "Twilight", Abby says that "McGee didn't just sleep in the coffin".

This is later followed up in the season 3 episode "Mind Games", Abby states "I am a scientist, McGee. Luck has nothing to do with it and/or us."

Did McGee and Abby ever get into a relationship? Is this ever covered anywhere during NCIS?