immunology allergic disorders
Selective Antibody Deficiency With Normal Immunoglobulins (SADNI)
Introduction
Selective antibody deficiency with normal immunoglobulins (Ig) is characterized by deficient specific antibody response to polysaccharide antigens but not to protein antigens, despite normal or near normal serum levels of immunoglobulins, including IgG subclasses. (See also Overview of Immunodeficiency Disorders and Selective antibody deficiency with normal immunoglobulins (SADNI) is a Primary Immunodeficiencies . It is one of the most common immunodeficiencies that manifests with recurrent sinopulmonary infections. Selective antibody deficiencies can occur in other disorders, but SADNI is a primary disorder in which deficient response to polysaccharide antigens is the only abnormality (see table A subset of patients with SADNI initially have an appropriate response to polysaccharide antigen but lose antibody titers within 6 to 8 months (called SADNI memory phenotype). Patients have recurrent sinopulmonary infections and sometimes manifestations that suggest atopy (eg, chronic rhinitis, Atopic Dermatitis (Eczema) , Young children may have a form of SADNI that resolves spontaneously over time. 