This volume contains the first section of the proceedings of a large, comprehensive meeting held in Sorrento, Italy. Because the meeting focused on such an important area of human health, four volumes have been dedicated to it: Part A presents new principles in autoimmunity, including the roles of key players such as designed ankyrin repeat proteins, SLAM-associated protein, interleukin-12, human proteinase 3, the complement system, IgG, disturbances in cytokine synthesis, and IFN-γ blockers. The second section of the volume takes a look at new diagnostic tools, including screening of endothelial expression libraries, electrical skin impedance, and IgA anti-tissue transglutaminase antibody assays. continues the presentation of basic research and its applications with a focus on genetics. Parts C and D present the clinical research in various manifestations of autoimmune disease and its treatments.