Antibodies are also known as Immunoglobulins. They're made by our immune system as a line of defence against foreign substances, such as bacteria, viruses and fungi. People with autoimmune diseases have antibodies that attack healthy cells in the body. The five major types of antibodies are: IgM, IgE, IgA, IgG and IgD.
As the body's first responders to an infection, IgM are found in the lymph fluid and blood. Though not the most common, IgM antibodies are the biggest. Normal IgM levels for adults are 55 to 375 milligrams per decilitre. High levels of IgM often indicate a new infection is present, since they are the first responders. People with low levels of IgM may have an inherited autoimmune disease or have Leukemia.
Known as the allergy responders, IgE antibodies are found in the lungs, mucous membranes and skin. They react against allergens such as spores, pet dander, pollen and fungi. Normal IgE levels in an adult are 4.2 to 592 units per millilitre. People with parasites or allergies have high levels of IgE. Those with low levels of IgE often have a rare inherited disease of the muscles, called ataxia-telangiectasia.
IgA antibodies are present in areas that first come into contact with foreign substances. They're found in the saliva, tears, nose, mouth, breathing passages, digestive tract and other 'front line' places. The normal IgA level range for adults is 85 to 385 milligrams per decilitre. Higher than normal levels of IgA are found in people with autoimmune disease and liver disease. Lower levels are found with people who have kidney disease, intestinal problems or Leukemia.
IgG antibodies are located in our bodily fluids. Because the antibodies are found in fluids, they're the only antibodies that can pass to a foetus through a mother's placenta. These are the most common antibody and are extremely important in terms of fighting off infection. Normal IgG levels in adults are from 565 to1765 milligrams per decilitre. High IgG levels are found in people who have chronic infections like HIV. Kidney damage and Leukemia are found in people with low levels of IgG.
The most mysterious of the antibodies, IgD are found in the tissue lining of the chest and stomach. The normal range of IgD levels for adults is less than 8 milligrams per decilitre. It is currently unknown how high or low levels of IgD may affect the human body.