Recent insights into the pathobiology of innate immune deficiencies.

Primary immunodeficiencies are a heterogeneous group of genetically inherited diseases affecting the innate and adaptive immune systems that confer susceptibility to infection, autoimmunity, and cancer. Innate immunity includes neutrophils, macrophages, dendritic cells, natural killer cells, and natural killer T cells in conjunction with natural barriers (mostly skin and gastrointestinal and respiratory mucosa), as well as antimicrobial agents, opsonins (e.g., complement), and cytokines. Although somewhat primitive, innate immune cells can orchestrate discrete immune responses through the recognition of diverse pathogens by different pattern-recognition receptors. In this review, we discuss the most recent discoveries as well as the already established pathophysiologic mechanisms underlying innate immunity defects associated with primary immunodeficiencies.