The Research Group in Immunodeficiencies and Transplantation Immunology was initially formed by professionals of the Immunology, Pediatrics and Organ Transplantation Areas of the Hospital 12 de Octubre with a view to developing scientific activities in the line of transplantation immunodeficiencies and immunology. Following its creation and evaluation by the i+12 Institute in 2009, it was formally qualified as a “consolidated group” on the basis of its solid and long-standing history. The research group is currently comprised by a total of 20 researchers (pre-doctoral, post-doctoral, junior and senior researchers). Five professionals of this group often raise funds for research and work as the principal investigators of a total of 12 projects that have been approved in competitive calls over the last 5 years. The group publishes regularly in international scientific journals (36 publications in 2016). In addition, it directs bachelor’s/master’s and doctoral theses (2 and 6 respectively in 2016). In 2013, it received a grant issued by the Healthcare Research Fund-Healthcare Institute Carlos III (FIS-ISCIII, Fondo de Investigación Sanitaria – Instituto de Salud Carlos III) along with another 6 research groups of the i+12 Institute for an Excellence Project concerning Organ Transplantation. Moreover, it holds the Spanish patent for a product designed to treat a primary immunodeficiency (ES253504). It frequently participates in research projects being carried out at a European level (it is currently involved in project DRKS000000497 of the Albert Ludwigs Universität of Freiburg, Germany: “A prospective outcome study on patients with profound combined immunodeficiency”) and is part of European initiative COST-Mye-Euniter (European Network of Investigators Triggering Exploratory Research on Myeloid Regulatory Cells).