Lacking an "official" definition, ARC is a condition in which some of the symptoms of AIDS have surfaced, but none of the usual opportunistic infections used to categorize a case of AIDS have appeared. Believed to be a lesser response to the AIDS virus, persons with ARC may exhibit such AIDS-related symptoms as swollen glands, night sweats, diarrhea, and unexplained fatigue without necessarily developing one of the opportunistic infections that would meet the criteria for a diagnosis of AIDS.