CHICAGO (AP) _ Warren Casey, a lyricist and author who helped write the hit musical ''Grease,'' died after a 10-month battle with AIDS. He was 53.

Casey, who died Tuesday at St. Joseph's Hospital, had battled acquired immune deficiency syndrome since February but continued composing music, said his companion, Burt Cohen.

Casey was best known as a collaborator with Jim Jacobs of Chicago in ''Grease,'' a joyous look at high school in the 1950s. The musical, which appeared on Broadway, later was the basis for a movie of the same name.

''In many ways, 'Grease' typified the energy and spirit of Chicago theater way before what we now refer to as the Chicago Theater Movement,'' said Dennis Zacek, artistic director of the Victory Gardens Theater, which included Casey on its original artistic board.

A native of Yonkers, N.Y., Casey earned a degree in fine arts at Syracuse University and later taught in New York high schools.

He came to Chicago in the 1960s and met Jacobs while acting with the Chicago Stage Guild.