CD4 and severe combined immunodeficiency: The key role of CD4+ T cells in protection from C. albicans overgrowth has become apparent through the increased frequency of severe and chronic forms of superficial C. albicans infections in individuals with inherited or acquired T cell deficiencies, such as severe combined immunodeficiency or acquired immune deficiency syndrome, respectively.20,21 Among CD4+ T cells, especially those secreting IL-17 are critical for control of C. albicans.