Defects in intrinsic and innate immunity

Abstract Innate immunity consists of phagocytic cells such as neutrophils, macrophages, dendritic cells, or intermediate cells (penumbra between innate and adaptive immunity) such as natural killer (NK) cells, and NK-T cells accompanied by natural barriers (skin epithelial layers and antimicrobial secretions and gastrointestinal and respiratory mucosa), and cytokines. Innate Immunity receptors that are called pattern recognition receptors (PRRs) are either cell-associated (e.g., Toll-like Receptor) or soluble (e.g., complement proteins) that can recognize numerous pathogen-associated molecular patterns or damage-associated molecular patterns. Some defects in each part of this integrated system involved in bacterial defense may result in pyogenic infections. We have provided in this chapter an appropriate or timely diagnosis and management guideline of innate immunodeficiency which can enhance the outcome of the disease treatment and provide more insight into introducing cost-effective and accurate predictive, diagnostic, and prognostic approaches to lessen the burden of the disease for patients, their families, and healthcare systems in the future.