ABSTRACT

Primary immune deficiency disease (PIDD) is a hereditary disorder, attributable to inherent defects in diverse elements of the immune system. PIDD causes susceptibility to infections and is frequently associated with a tendency to autoimmunity and/or immune dysregulation. Up-to-date, more than 330 PIDD have been defined and the molecular (genetic) origins for more than 320 of them are described. In this group, primary antibody deficiencies are the most common group and approximately 50% of PIDD patients have this defect. Clinical findings of PIDD typically appear early in life, although cases with delayed onset are progressively more documented. Affected PIDD patients usually manifest in clinic with recurrent infections, severe infections, or both, plus autoimmunity development that are accompanied with most of the PIDD. Timely diagnosis is indispensable for transferring patients to specialized centers and the commencement of proper treatment including stem cell transplantation. Consequently, the prompt diagnosis of PIDD is necessary for best possible management and better outcomes. In this review, a basic approach for the exploration of the most common PIDDs is described, outlining some of the typical clinical findings and most appropriate laboratory investigations from simple complete blood count to advanced genetic tests such as next generation sequencing.