Kelesidis et al. in 2010 [49] published a review comprising 152 patients with Good’s syndrome and included the following defining aspects of immunodeficiency: hypogammaglobulinemia, low or absent B cells, variable defects in cell-mediated immunity with a CD4 T lymphopenia, an inverted CD4/CD8+ T-cell ratio and reduced T-cell mitogen proliferative responses. The gene discussed is CD4; the disease is lymphopenia.