Specific antibody deficiency describes a deficient-specific antibody response to polysaccharide antigens in an individual with normal responses to protein antigens, normal serum levels of immunoglobulins, and normal IgG subclass concentrations.
This topic will discuss the epidemiology, pathogenesis, evaluation, diagnosis, and management of this disorder. A detailed discussion of the interpretation of vaccine responses and an overview of humoral immune deficiencies are presented elsewhere. (See "Assessing the immunologic response to vaccination" and "Primary humoral immune deficiencies: An overview".)
Specific antibody deficiency was first reported in a small group of patients in the early 1980s [1,2]. Subsequently, it was established that a deficient-specific antibody response to polysaccharide antigens can be seen in both children and adults [3-6]. It is one of the most commonly identified immune defects among patients presenting with recurrent and/or severe sinopulmonary infections. (See 'Epidemiology' below.)
Specific antibody deficiency may be identified as part of a host of distinct primary or secondary immunodeficiency disorders, such as common variable immune deficiency or asplenia, or it may exist in isolation, as the only identifiable immune problem [7-12].
Terminology — The terminology for specific antibody deficiency or polysaccharide nonresponse is not standardized, and other names appear in the literature, including "impaired polysaccharide responsiveness" and "selective antibody deficiency with normal immunoglobulins." In this review, specific antibody deficiency refers to the condition in which polysaccharide nonresponse is the only identifiable abnormality. We use the descriptive term "polysaccharide nonresponse" to denote the immunologic defect, which may occur in a variety of disorders.