European and American doctors added new reports today to earlier descriptions of patients with an AIDS-like disease but no detectable evidence of infection with H.I.V., the virus that causes AIDS. American health officials appealed to doctors today to report any similar cases to the Federal Centers for Disease Control. Dr. James Curran, an AIDS expert at the [CDC] in Atlanta, said here it was not clear whether the known cases represent a new syndrome or a variety of rare medical problems that pose no threat to the nation's health. The plea resulted from a ... meeting at which Dr. Jeffrey Laurence of Cornell University Medical Center in New York City described five such cases that are due to be reported soon in the Lancet, a British medical journal. At the C.D.C., Dr. Thomas J. Spira has collected reports of six patients over the last 3 years. Dr. Spira saw no pattern among them. The reports from Dr. Laurence and Dr. Curran were greeted by a parade of scientists who reported more than a dozen similar cases. By the time the [meeting] ended, Dr. Curran said he learned of more cases in a few minutes today than he had in the last three years. Reports of additional cases from doctors in Edinburgh and the Hague followed, [along with] criticism at the Centers for Disease Control for not having reported the six cases it knew about and for not issuing an earlier plea to doctors to report additional ones.