Britannica
Sources used in this answer
- immune system disorder - Immune deficiencies
- autoimmune disease
- human disease - Immune deficiencies
- human disease - Allergies
- human disease - The immune response
- immune system disorder - Malignant transformation of lymphocytes
- immune system disorder
- immune system disorder - Cancers of the lymphocytes
- disease - Immunity
Which major categories of immune system disorders can cause disease?
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immune system disorder
False-color scanning electron micrograph of a T cell infected with HIV (human immunodeficiency virus), the agent that causes AIDS (acquired immunodeficiency syndrome).
Immune system disorders occur when the body's defense mechanisms fail or function inappropriately, leading to disease. These disorders are generally categorized into the following major groups:1
- Immune deficiencies: These result from a diminished or absent immune response, leaving the body unable to effectively resist infections. They can be inherited (genetic) or acquired through factors such as infectious agents (e.g., HIV), medical treatments, or other diseases like cancer.213
- Allergies: Also known as hypersensitivity, these occur when the immune system mounts an inappropriate, often harmful, response to normally harmless foreign substances in the environment, such as pollen or certain foods.41
- Autoimmune disorders: In these conditions, the immune system malfunctions and reacts against the body's own normal cells or tissues, treating them as foreign antigens.51
- Cancers of the lymphocytes: These arise when white blood cells, specifically lymphocytes, undergo malignant transformation and proliferate uncontrollably, resulting in conditions such as leukemias, lymphomas, and myelomas.617