- Humoural (65%): B cell defects
- X-linked agammaglobulinemia
- Common variable immune deficiency (CVID)
- Transient hypogammaglobulinemia of infancy
- Hyper-IgM syndrome
- IgA deficiency
- Cell-mediated (5%): T-cell deficiencies
- DiGeorge syndrome
- Chronic mucocutaneous candidiasis
- Combined (15%): B- and T-cell deficiencies, often much more severe
- Severe combined immunodeficiency disease (SCID)
- Wiskott-Aldrich syndrome
- Ataxia-telangiectasia
- X-linked lymphoproliferative disease
- CD40 ligand deficiency
- Phagocytic (10%): neutrophil deficiencies
- Phagocyte deficiencies
- Chronic granulomatous disease (CGD)
- Leukocyte adhesion deficiency
- Complement (5%)