D81: Combined immunodeficiencies

Combined immunodeficiencies refer to a diverse group of diseases that are characterized by a severe disruption in the immune system. This makes the body more susceptible to infections from bacteria, viruses, fungi, and other harmful microorganisms. Genetic defects primarily cause these conditions—usually inherited from parents—and affect key components of the immune system. These defects typically impair both the body's ability to produce specific antibodies (which protects against bacteria and viruses), and its ability to generate T cells (which defend against a broad range of threats). Common symptoms often include recurrent, persistent, or severe infections that can affect various systems in the body such as the respiratory system or the digestive system. As these diseases progress, if left untreated, they can potentially become life-threatening due to an increased risk of severe infections and complications.