CARLOS LOPEZ-LARREA is Professor of Immunology (UC M, Madrid, Spain) and currently Head of the Histocompatiblity Unit at the "Hospital Universitario Central de Asturias" (Oviedo, Spain). He is a world expert on spondyloarthropathies (SpA), in particular genetic (MHC) and immunologic factors that influence the development of SpA. His primary research is focused on understanding the role of HLA-B27 polymorphism in the development of ankylosing spondylitis (AS), and describing relevant associations of B27 subtypes with AS in large extended worldwide populations. In the last decade, the availability of HLA-B27 subtypes differentially associated with the disease has provided a unique tool for exploring the relationship between peptide specificity and pathogenetic potential. The main research interests of his group currently include the role of innate immunity (NKs) in SpA. He is a member of several national and international scientific organizations. It is now over ten years since the first edition of HLA-B27 in the Developement of Spondyloarthropathies (SpA) was published and edited by C. Lopez-Larrea. This current book aims to synthesize the growing knowledge in the field and present all current studies concerning basic research in SpA. ROBERTO DIAZ -PENA is a predoctoral investigator in the Histocompatibility Unit of the Department of Immunology, Hospital Universitario Central de Asturias. He graduated in biochemistry, at the University of Oviedo, Spain. His main research interests include the genetics of spondyloarthropathies, especially ankylosing spondylitis, and the role of inhibitory and activating KIR receptors in this disease.