Key aspects for successful immunoglobulin therapy of primary immunodeficiencies.

Immunoglobulin (Ig) therapy is the mainstay for treatment in the majority of primary immune deficiencies. While B cell defects are the predominant conditions in man, other diseases in which T cell dysfunction is severe also require antibody replacement. In many medical practices the phenotypic overlap between immune deficiency and symptoms of asthma leads to both missed opportunities for diagnosing immune defects and inappropriate Ig treatment of asthmatic patients with normal B cell function. As steroid therapy can lower serum IgG levels, this finding alone is an insufficient indicator for Ig replacement. In the past 3 decades, there has a gradual increase in recommended and commonly used doses of parenteral immune globulin, often based on both IgG trough levels and clinical responses. Special attention to Ig doses is needed for growing children, in cases of weight loss or gain, pregnancy and for subjects in whom more rapid consumption of Ig is likely, including febrile patients or those with gastrointestinal or lung disease. While acute bacterial infections are much less common in Ig-treated subjects, a number of reports note continued evidence of inflammatory complications. Monitoring patients over time includes, at minimum, physical examination, blood counts and chemistry screening tests and IgG trough levels, at 6-12-month intervals. Other monitoring tools include spirometry and at wider intervals with those with lung disease, carbon monoxide diffusion capacity and chest computed tomography scans. With careful selection of patients and adequate therapy, an improved quality of life is possible.