<unk>  is a form of hypogammaglobulinemia where the serum concentrations of one or more subclasses of<unk>  are diminished relative to other immunoglobulin isotypes, meanwhile total<unk>  concentration is noral.<unk>  is a laboratory finding that may be not associated with significant clinical presentations. The diagnosis of a clinically significant<unk>  needs evidence of antibody dysfunction in the form of recurrent infections and an inadequate response to vaccine challenge.
Most patients with<unk>  are usually asymptomatic. Symptoms of<unk>  may include the symptoms of recurrent sinopulmonary infections include otitis media, rhinosinusitis, and pneumonia or even more serious infections that can occur such as osteomyelitis, meningitis, septicemia, diarrhea, and skin infections.<unk>  has four subclasses:<unk> 1,<unk> 2,<unk> 3, and<unk> 4. It is possible to have either a global<unk> , or a<unk>  of one or more specific subclasses of<unk> .  Since<unk> 1 forms about 70 percent of total<unk>  patients with <unk>  are classified as common variable immunodeficiency (CVID), a diagnosis that also needs reduced levels of IgA and/or IgM.<unk> 2 subclass<unk>  is the main clinically relevant form of<unk>   and is more prevalent among children than adults and is one of the most frequently identified disorders in children with recurrent infections in children or may present as transient hypogammaglobulinemia of infancy (THI), and may occur with or without additional reduction in IgA or IgM.<unk>  is not usually encountered without other concomitant immunoglobulin<unk> es, and<unk>  is very common but usually asymptomatic.
The diagnosis of a clinically significant<unk>  needs evidence of antibody dysfunction in the form of recurrent infections and an inadequate response to vaccine challenge. Management consists of immunization with conjugate vaccines in patients who have not responded to polysaccharide vaccines, aggressive treatment of other conditions predisposing to recurrent sinopulmonary infections and appropriate antibiotic therapy for infections and the use of prophylactic antibiotics for patients with repeated sinopulmonary infections.
Intravenous or subcutaneous immune globulin replacement should be reserved for patients with clearly impaired responses to protein and/or polysaccharide antigens and/or if the use of prophylactic antibiotics does not cause fewer infections or in patients with persistent and symptomatic chronic rhinosinusitis .
IgG deficiency
Primary immunodeficiency
Immunoglobulin M deficiency
Selective immunoglobulin A deficiency
Natural killer cell deficiency
Complement deficiency
Leukocyte adhesion deficiency
Hyper-IgE syndrome