Humoral Immunodeficiency and Immune Globulin Replacement Therapy (IGRT) Usage in DiGeorge Syndrome.

PURPOSE An analysis of patients in the United States Immunodeficiency Network (USIDNET) registry previously described a discordance in the reported prevalence of humoral immune deficiency in patients with DiGeorge syndrome (DGS) and its treatment. The primary purpose of this study is to evaluate the rates of humoral immunodeficiency and immune globulin replacement therapy (IGRT) use in patients with DiGeorge syndrome in the USIDNET registry as of September 2016, and to correlate IGRT use with prior infections and laboratory evidence of immune deficiency. METHODS Current patients in the USIDNET registry with DGS were identified. Patients who were treated with immune globulin replacement therapy (IGRT) were compared with those who were untreated with respect to their laboratory findings and clinical history. RESULTS Four hundred seventy-three patients were identified. The use of IGRT in patients with DGS has increased over time from 3 to 6.6%. IGRT was more common in patients with humoral immune deficiency (18.2% of those with hypogammaglobulinemia, 39.1% of those with documented low vaccine titers), but most patients with evidence of humoral immune deficiency remain untreated with IGRT. Patients treated with IGRT were more likely to have experienced episodes of pneumonia, sepsis, and bacterial skin infections (p < 0.01 for all). CONCLUSIONS Humoral immune deficiencies were more common among patients with DGS than previously reported. IGRT was used most commonly in patients with DGS who demonstrated frequent or severe bacterial infections. There is still a significant deficit between those with DGS who have laboratory evidence of a humoral immune deficiency and those being treated for it.