Infections, such as tuberculosis and influenza, are still wonders. Since multicellular organisms, such as humans, are always being exposed to invasions of pathogens, recognition and exclusion of the pathogenic organ by activation of an immunological system are among the constant maintenance mechanisms for a multicellular organism to be materialized. Especially, innate immunity is an immune system that functions in the early stages of pathogen infection. Activation of acquired immunity is induced by the activation of innate immunity. Innate immunity is indispensable to the initial response of infection. Furthermore, by research in recent years has been reported, being deeply concerned with the onset of autoimmune diseases, such as systemic lupus erythematosus (SLE). In this paper, it starts in the initial response of pathogen infection and outlines the role of innate immunity in the development of symptoms of diseases, such as an autoimmune disease.