γ2 isotype deficiency

IgG sublass deficiency is clinically significant only if an impaired response to bacteria such as tetanus, diphteria, and pneumococcus occurs. Antipneumococcal antibodies for IgG2 should be checked if the titers for total Igs are normal and the patient is unable to produce antibodies to specific antigens. IgG2 deficiency may be associated with an inability to have a response to polysaccharides, leading to recurrent sinopulmonary infections with encapsulated bacteria such as H. influenza and S. pneumoniae. Asymptomatic cases of IgG2 deficiency have been reported, and some patients without IgG2 will not respond to polysaccharide antigens.