Omenn Syndrome—Immune System and Disorders

Your immune system is a complex network of cells, tissues, and organs that work together to defend against germs. It helps your body to recognize these “foreign” invaders. Then its job is to keep them out, or if it can’t, to find and destroy them.

If your immune system cannot do its job, the results can be serious. Disorders of the immune system include

• Allergy and asthma – immune responses to substances that are usually not harmful
• Immune deficiency diseases – disorders in which the immune system is missing one or more of its parts
• Autoimmune diseases – diseases causing your immune system to attack your own body’s cells and tissues by mistake

NIH: National Institute of Allergy and Infectious Diseases

• Agammaglobulinemia (Medical Encyclopedia)
• Aging changes in immunity (Medical Encyclopedia)
• Chronic granulomatous disease (Medical Encyclopedia)
• Graft-versus-host disease (Medical Encyclopedia)
• Histiocytosis (Medical Encyclopedia)
• Hyperimmunoglobulin E syndrome (Medical Encyclopedia)
• Immune response (Medical Encyclopedia)
• Immunodeficiency disorders (Medical Encyclopedia)
• Selective deficiency of IgA (Medical Encyclopedia)

Omenn syndrome is an inherited disorder of the immune system (immunodeficiency). Omenn syndrome is one of several forms of severe combined immunodeficiency (SCID), a group of disorders that cause individuals to have virtually no immune protection from bacteria, viruses, and fungi. Individuals with SCID are prone to repeated and persistent infections that can be very serious or life-threatening. Infants with Omenn syndrome typically experience pneumonia and chronic diarrhea. Often the organisms that cause infection in people with this disorder are described as opportunistic because they ordinarily do not cause illness in healthy people.In addition to immunodeficiency, children with Omenn syndrome develop autoimmunity, in which the immune system attacks the body’s own tissues and organs. This abnormal immune reaction can cause very red skin (erythroderma), hair loss (alopecia), and an enlarged liver and spleen (hepatosplenomegaly). In addition, affected individuals have enlargement of tissues that produce infection-fighting white blood cells called lymphocytes. These include the thymus, which is a gland located behind the breastbone, and lymph nodes, which are found throughout the body.If not treated in a way that restores immune function, children with Omenn syndrome usually survive only until age 1 or 2.