Selective IgG subclass deficiency: quantification and clinical relevance

Abstract

Each of the four human IgG subclasses exhibits a unique profile of effector functions relevant to the clearance and elimination of infecting microorganisms. The quantitative response within each IgG subclass varies with the nature of the antigen, its route of entry and, presumably, the form in which it is presented to the immune system. This results in antibody responses to certain antigens being predominantly or exclusively of a single IgG subclass. An inability to produce antibody of the optimally protective isotype can result in a selective immunodeficiency state. This is particularly apparent for responses to certain bacterial carbohydrate antigens that are normally of IgG2 isotype. A failure to produce the appropriate specific antibody response may result in recurrent upper and/or lower respiratory tract infection. Careful patient investigation can identify such deficiencies and suggest appropriate clinical management. In this review we outline the biology and clinical relevance of the IgG subclasses and summarize current rational treatment approaches.

Nanoparticle size and surface properties determine the protein corona with possible implications for biological impacts

“…Immunoglobulins (IgGs) of the type identified on the particles are involved in many processes from immunity response to allergic reaction and anaphylactic shock. IgG is involved in transport across the placenta, as well as the general process of opsonization for presentation to macrophage, for example (8).…”

Selective subnormal IgG3 in 121 adult index patients with frequent or severe bacterial respiratory tract infections

“…Selective subnormal IgG1 levels have been reported in adults and children, many of whom presented with recurrent respiratory tract infections [4][5][6][7]. Some adults with selective subnormal IgG1 also have autoimmune conditions [6], atopy [6], or suboptimal responses to polyvalent pneumococcal polysaccharide vaccination (PPPV) [7].…”

Specificity of IgG subclass antibodies in different clinical manifestations of leprosy

“…Human IgG is composed of four subclasses whieh differ In structure and biological activities such as binding capacity to mononuclear phagocytic cells, reaeting with staphylocoecal proteins and activating complement fixation [12). The quantitaCtirrcspondcnce: Dr S. Dhandayuthapani.…”