Chronic granulomatous disease: a review of the infectious and inflammatory complications

Primary immune deficiencies often present as recurrent infections, often with unusual pathogens, or infections of unusual severity or frequency. Host defense consists of either nonspecific or specific mechanisms of immunity to invading pathogens (Table 1). Nonspecific mechanisms include barrier functions of skin and mucosa (tears, saliva, mucosal secretions, mucociliary responses, and clearance by peristalsis as occurs in the bladder or the gastro-intestinal system), phagocyte responses (neutrophils, macrophages or mononuclear cells and their component of pathogen recognition receptors or PRR and cell adhesion molecules or CAMs), complement system of proteins, C reactive protein (CRP), cytokines, and the PRRs mentioned earlier on the surface of a variety of cell types. Specific immune responses include immunoglobulin class switching and secretion by B lymphocytes/plasma cells and T lymphocyte responses (including antigen recognition, clonal proliferation, and cytokine synthesis resulting in B cell and phagocyte activation and survival).Innate immunity occurs rapidly and is relatively nonspecific, while adaptive responses occur later and are characterized by activation of the T and B lymphocytes, antigen recognition, cognate interaction using several key cell surface receptors (discussed later) and the synthesis and secretion of antibodies, cytokines and other effector molecules that lead to an expansion of the specific immune response towards a pathogen (Table 2). There are close interactions between the nonspecific/innate and adaptive immune responses, such that a two-way response as well as independent responses regulate overall immune function. To further add a complex dimension to this process is the recent discovery and description of several regulatory T cell subsets including the T regulatory (T reg/Tr1 and Th3 subset) and the Th17 subset of lymphocytes that oversee overall immune function. The description of these aspects is beyond the scope of this review b