Immune system defects in DiGeorge syndrome and association with clinical course.

We evaluated 18 DiGeorge syndrome (DGS) patients and aimed to investigate the immunological changes in this population. DGS patients with low naive CD4+ T and CD8+ T cells were defined as high-risk (HR) patients, whereas patients with normal numbers of naive CD4+ and CD8+ T cells were defined as standard risk (SR) patients. Level of serum IgM, CD3+ T cell counts and percentages of class-switched memory B cells were significantly low in HR group compared to SR ones. Severe infections and persistent hypoparathyroidism were detected significantly higher in HR group. Patients with reduced percentages of class-switched B cells had earlier onset of infection, lower blood IgM, lower CD4+ and CD8+ T counts than patients with normal class-switched memory B cells. Decreased levels of IgM were associated with low numbers of naive CD4+ and recent thymic emigrants T cells. Monitoring the immune changes of patients with DGS would be useful to predict the severe phenotype of disease.