Thus, infection-generated IgG and IgM are detected from serum and plasma samples by sandwich ELISA or lateral flow immunoassays; the detection of the extraordinary IgG antibody expression caused by cancer and autoimmune disease is determined by sandwich immunoassays [176]; and conventional determinations of IgE also employ antibody-based sandwich ELISA, RAST (Radio Allergo-Sorbent Test in serum) or immunoblot tests [51]. The gene discussed is IGHE; the disease is autoimmune disease.