“…PRL is structurally related to members of the cytokine/hemopoietin family [1] and receptors for PRL are widely distributed in the immune system [2,3]. Studies have revealed PRL as a lymphocyte growth factor [4]. PRL induces IL-2 receptors [5] on the surface of lymphocytes, stimulates the production of IFN-␥ by lymphocytes [6] and increases nitric oxide and IL-1 production by macrophages [7].…”