Waiver
As in criminal courts, the privilege against self-incrimination can be waived in civil and other proceedings, and it is “most commonly waived when a client simply answers the question posed.” This extends beyond the courtroom and waiver can even be found where the litigant made an “affirmative denial of an allegation in a pleading.”
In fact, during a recent Congressional hearing, an IRS official may have done exactly that – waived her right against self-incrimination. While appearing before the Oversight and Government Reform committee, Lois Lerner read a brief statement where she insisted: “I have done nothing wrong.” According to Harvard Law professor Alan Dershowitz:
You can’t simply make statements about a subject and then plead the Fifth in response to questions about the very same subject . . . . Once you open the door to an area of inquiry, you have waived your Fifth Amendment right . . .you’ve waived your self-incrimination right on that matter.
http://www.todayifoundout.com/index.php/2014/01/can-people-held-contempt-invoking-5th-amendment/