European Parliament president David Sassoli has been hospitalized in Italy due to abnormal functioning of his immune system, his spokesman said Monday.

Roberto Cuillo said in a statement that Sassoli has in the hospital since Dec. 26 and all his activities have been cancelled.

“This hospitalization was necessary because of a serious complication due to a dysfunction of the immune system," the statement added.

Sassoli, 65, suffered a severe case of pneumonia in September during a plenary session of the Parliament and had to be hospitalized. He returned to Italy to recover but had a relapse that kept him away from his duties for a while.