Immunodeficiency occurs when the body's immune system is weakened or doesn't function correctly, making individuals more susceptible to infections and other diseases. The causes can broadly be categorized into primary and secondary types.
Primary Immunodeficiency
Primary immunodeficiency disorders (PIDs) are conditions that are inherited, meaning they are passed down genetically from parents to children.
As stated in the reference, many primary immunodeficiency disorders are inherited — passed down from one or both parents. Problems in the genetic code that acts as a blueprint for producing the cells of the body (DNA) cause many of these immune system defects. These genetic defects can affect the development or function of various immune cells or proteins, such as antibodies, T cells, or complement proteins.
Examples of primary immunodeficiencies include:
- Severe Combined Immunodeficiency (SCID)
- Common Variable Immunodeficiency (CVID)
- X-linked Agammaglobulinemia (XLA)
- Chronic Granulomatous Disease (CGD)
Secondary Immunodeficiency
Secondary immunodeficiency, also known as acquired immunodeficiency, occurs later in life and is not inherited. It develops as a result of other external factors or underlying medical conditions.
Common causes of secondary immunodeficiency include:
- Infections: Certain infections, most notably the Human Immunodeficiency Virus (HIV), can severely damage immune cells.
- Medical Treatments:
- Chemotherapy and radiation therapy for cancer.
- Immunosuppressant medications used to treat autoimmune diseases or prevent organ transplant rejection.
- Malnutrition: Lack of essential nutrients can impair immune function.
- Certain Cancers: Cancers affecting the bone marrow (like leukemia or lymphoma) can disrupt the production of healthy immune cells.
- Other Chronic Diseases: Conditions such as diabetes, kidney disease, or sickle cell anemia can weaken the immune system over time.
- Aging: The immune system naturally becomes less effective with age.
Understanding the cause of immunodeficiency is crucial for proper diagnosis and management, guiding treatment strategies to either correct the underlying defect (in some primary cases) or manage the condition causing the immune system weakness (in secondary cases).
