Immune

Immunoglobulins (Igs) are the instrumental proteins of immunity. Immunity is a property of the lymphoid system which is made of organs (spleen, thymus, bone marrow) and of cells (lymphocytes). Circulating immunoglobulins are secreted in the blood by B lymphocytes and they thereby export far-away the specific biological functions of humoral immunity.

• Immunoglobulin M (IgM) is the first Ig to appear in response to an antigenic stimulus such as an infectious agent. In many cases, the antigen-specific IgM level subsequently falls and remains low as the IgG response appears.
• Immunoglobulin G (IgG) - the predominant serum immunoglobulin (75 % of Igs)- is of particular importance in the body’s long-term defense against infection; IgG serum levels are increased in response to chronic or recurrent infections or autoimmune diseases.
• Immunoglobulin A (IgA) is the major Ig found in secretions, playing a major role in the protection of the respiratory, genitourinary, and gastrointestinal tracts against infection.
• Immunoglobulin E (IgE) – IgE is associated with allergies, allergic diseases, and with parasitic infections. It is almost always measured as part of an allergy testing blood panel but typically is not included as part of a quantitative immunoglobulins test.
  
  

Immunoglobulins testing measures the total amount of each primary immunoglobulin class, IgA, IgM, and IgG, without distinguishing between subclasses. Separate testing can be performed to measure immunoglobulin subclasses and/or to detect and measure specific antibodies.