Bare Lymphocyte Syndrome Type II – 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)

Bare lymphocyte syndrome type II (BLS II) is an inherited disorder of the immune system categorized as a form of combined immunodeficiency (CID). People with BLS II lack virtually all immune protection from bacteria, viruses, and fungi. They are prone to repeated and persistent infections that can be very serious or life-threatening. These infections are often caused by “opportunistic” organisms that ordinarily do not cause illness in people with a normal immune system.BLS II is typically diagnosed in the first year of life. Most affected infants have persistent infections in the respiratory, gastrointestinal, and urinary tracts. Because of the infections, affected infants have difficulty absorbing nutrients (malabsorption), and they grow more slowly than their peers. Eventually, the persistent infections lead to organ failure. Without treatment, individuals with BLS II usually do not survive past early childhood.In people with BLS II, infection-fighting white blood cells (lymphocytes) are missing specialized proteins on their surface called major histocompatibility complex (MHC) class II proteins, which is where the condition got its name. Because BLS II is the most common and best studied form of a group of related conditions, it is often referred to as simply bare lymphocyte syndrome (BLS).