215 ILCS 165/26

A health services plan corporation incorporated prior to January 1, 1965, operated on a not for profit basis, and neither owned or controlled by a hospital shall not be liable for injuries resulting from negligence, misfeasance, malfeasance, nonfeasance or malpractice on the part of any officer or employee of the corporation, or on the part of any person, organization, agency or corporation rendering health services to the health services plan corporation's subscribers and beneficiaries.