In the second stage Aids Related Complex (ARC) appears (the patient must be ill for three months with no apparent other cause to be judged in the ARC stage). The lymph glands swell, body weight drops, there is continuous fever, exhaustion, and sweating.
所謂「ARC 臨床癥候」（須出現三個月以上，且無法解釋病因），指的是多處淋巴腺腫大、體重大幅減輕、持續高燒、腹瀉、倦怠無力、夜間盜汗等。