The House issued a subpoena for all relevant communications - Dept of State, DoD, White House - on the Benghazi matter last year. Nothing was turned over to Issa's committee. Then this week following a court order Judicial Watch gets the emails that Issa's committee didn't get from the White House and the State Dept. Issa is pissed, and for good reason.
However, calling Kerry to testify is a risky move. He might bore Issa's committee to death and completely derail the investigative process.
http://oversight.house.gov/wp-conten...ver-letter.pdf