The Lab Notebook

Antinuclear Antibodies and the IFA Test

Posted by Jon Richards on Mar 30, 2015 3:40:59 PM

ANARNP2-20-06-02Antibodies are produced in abundance by the human immune system. The white blood cells are responsible for their manufacture, including lymphocytes (T-cells and B-cells) and antigen presenting cells. Their job is to produce a coordinated response to foreign substances (antigens) as well as to destroy harmful pathogens such as bacteria and viruses. The human body contains vast numbers and varieties of normal and essential human proteins called autoantigens. In some situations the body’s immune system makes an error and recognizes the normally occurring autoantigens as “foreign,” binding to them in order to destroy and eliminate them from the body. A specific subset of antibodies that attack normal proteins found in the nucleus of the cell are called, not surprisingly, antinuclear antibodies, or “ANAs” for short. These misguided antibodies direct their attack against the cell’s nucleic acids and sometimes their associated proteins which are found in or near the nucleus of the cell. Elevated levels of ANAs have been associated with various rheumatic diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis, Sjögren's syndrome, scleroderma, polymyositis, dermatomyositis and various other systemic autoimmune diseases.

In 1957, ANAs were first demonstrated using indirect immunofluorescence (IF) by Holborow et al (1). Over the years the Indirect Immunofluorescence Assay (IFA) has been developed and used to detect and identify the ANA. The IFA is a laboratory test where specific antibodies in serum or other body fluids are bound to a fluorescent compound that gives a green glow when exposed to ultraviolet light, typically under a microscope. The IFA detection method has gained increasing acceptance by clinicians who use the information as an aid in the diagnosis and treatment follow‐up of ANA related diseases. Since 2009, The American College of Rheumatology has recommended the use of IFA to detect ANAs and it is still considered the “Gold Standard”. MBL International offers an ANA (Anti-Nuclear Antibody) Test System, an indirect fluorescent antibody assay utilizing HEp-2 tissue culture cells as a substrate for the qualitative and/or semi quantitative determination of antinuclear antibodies in human serum to aid in the diagnosis of certain autoimmune diseases. For more than 30 years we have been supplying a complete line of Autoimmune IFA products intended for semi quantitative detection of autoantibodies against various types of subcellular components including nucleic acids, nuclear proteins, and cytoplasmic proteins in human serum.

  1. Holborow EJ, Weir DM, Johnson GD. A serum factor in lupus erythematosus with affinity for tissue nuclei. Br Med J1957;2:732–40.