The team, led by Mr. Makarfi, visited former ministers, Femi Fani-Kayode, Bala Mohammed, Musiliu Obanikoro and former presidential spokesperson, Reuben Abati.
The detainees are accused of corruption, and each has been held for at least a week.
The PDP delegation also had the National Secretary, Ben Obi, National Publicity Secretary, Dayo Adeyeye, and the National Organising Secretary, Abdul Ningi.
They arrived the EFCC headquarters in Abuja at about 2:30p.m., a source at the commission said.
One source said the delegation encouraged all four detainees and expressed solidarity with them.
They assured all of them that the PDP family was solidly behind them and urged them to keep their heads held up high and remain strong.
The delegation also expressed happiness that the detainees were in high spirits.
Our sources said the four detainees expressed their gratitude to the delegation for the visit.