Acupuncture is a well-known form of Asian medical treatment and it is used not only as an effective curative method but also to prevent illness and maintain health. It is used for the production of analgesic effect; stress related physical-mental disorders and homeostasis. Electroacupuncture (EA) stimulation, an application of electrical current on acupuncture needles, is one of the most popular types of this traditional therapy. In recent years, intensive studies have been carried out to explain the underlying mechanisms of the efficacy of acupuncture. An increase in the release of endogen opioid peptides is generally accepted to be a keystone pathway that affects the immune system after the acupuncture application. To understand the huge gap between specific skin point applications and immune responses, a vast number of accumulating data of experimental and clinical studies in the literature have been collected. This paper reviews the data to explain the updated mechanisms related to immune modulation via acupuncture therapy.