Pharmabiz
 

Autoimmune responses

Balram ParathWednesday, April 22, 2009, 08:00 Hrs  [IST]

When the immune system mistakes self tissues for non self and mounts an inappropriate attack, the result is an autoimmune disease. The autoimmune diseases affect the body in different ways. For instance, the autoimmune reaction is directed against the brain in multiple sclerosis and the gut in Crohn's disease. In other diseases, such as systemic lupus erythematosus (lupus), affected tissues and organs may vary among individuals with the same disease. Our immune system is a complex network of specialised cells and organs that has evolved to defend the body against attacks by "foreign" invaders. Autoimmune diseases typically feature inflammation of various tissues of the body. Anti nuclear antibodies (ANAs) are found in patients with a number of different autoimmune diseases such as systemic lupus erythematosus, Sjogren's syndrome, rheumatoid arthritis, polymyositis, scleroderma, Hashimoto's thyroiditis, juvenile diabetes mellitus, Addison disease, vitiligo, pernicious anaemia, glomerulonephritis and pulmonary fibrosis. ANAs can also be found in patients with conditions that are not considered classic autoimmune diseases like chronic infections and cancer. Conditions causing ANA's to get produce ANAs can be produced in patients with infections (virus or bacteria), lung diseases (primary pulmonary fibrosis, pulmonary hypertension), gastrointestinal diseases (ulcerative colitis, Crohn's disease, primary biliary cirrhosis, alcoholic liver disease), hormonal diseases (Hashimoto's autoimmune thyroiditis, Grave's disease), blood diseases (idiopathic thrombocytopenic purpura, hemolytic anemia), cancers (melanoma, breast, lung, kidney, ovarian and others) and skin diseases (psoriasis, pemphigus). Causes of autoimmune disorder To further understand autoimmune disorders, it is helpful to understand the workings of the immune system. The purpose of the immune system is to defend the body against attack by infectious microbes (germs) and foreign objects. When the immune system attacks an invader, it is very specific - a particular immune system cell will only recognise and target one type of invader. To function properly, the immune system must not only develop this specialised knowledge of individual invaders, but it must also learn how to recognise and not destroy cells that belong to the body itself. Every cell carries protein markers on its surface that identifies it in one of two ways: what kind of cell it is (e.g. nerve cell, muscle cell, blood cell, etc.) and to whom that cell belongs. These markers are called major histocompatibility complexes (MHCs). When functioning properly, cells of the immune system will not attack any other cell with markers identifying it as belonging to the body. Conversely, if the immune system cells do not recognise the cell as "self," they attach themselves to it and put out a signal that the body has been invaded, which in turn stimulates the production of substances such as antibodies that engulf and destroy the foreign particles. In case of autoimmune disorders, the immune system cannot distinguish between "self" cells and invader cells. As a result, the same destructive operation is carried out on the body's own cells that would normally be carried out on bacteria, viruses, and other such harmful entities. Symptoms Symptoms of autoimmune disease vary widely depending on the type of disease. A group of very nonspecific symptoms often accompany autoimmune diseases especially of the collagen vascular type and include: ●fatigue ●dizziness ●malaise (nonspecific feeling of not being well) ●fever, low-grade temperature elevations Autoimmune disease results in ●destruction of an organ or tissue resulting in decreased functioning of an organ or tissue (for example, the islet cells of the pancreas are destroyed in diabetes ) ●increase in size of an organ or tissue (for example, thyroid enlargement in Grave's disease) Note: Symptoms vary with the specific disorder and the organ or tissue affected. Diagnosis A number of tests are involved in the diagnosis of autoimmune diseases, depending on the particular disease; e.g. blood tests, cerebrospinal fluid analysis, electromylogram (measures muscle function), and magnetic resonance imaging of the brain. Usually, these tests determine the location and extent of damage or involvement. They are useful in charting progress of the disease and as baselines for treatment. "As more testing options become available, the demand for autoimmune disease diagnostics is likely to increase." remarks Balram Parath, country manager of Bio-Rad Laboratories India Pvt Ltd. "As laboratories consolidate to gain improved productivity and cost-efficiencies, demand for quick and efficient laboratory tests increase, thereby fueling market growth." Adds Balram Parath. The principle tool, however, for authenticating autoimmune disease is antibody testing. Such tests involve measuring the level of antibodies found in the blood and determining if they react with specific antigens that would give rise to an autoimmune reaction. An elevated amount of antibodies indicates that a humoral immune reaction is occurring. Since elevated antibody levels are also seen in common infections, they must be ruled out as the cause for the increased antibody levels. Antibodies can also be typed by classes. There are five classes of antibodies, and they can be separated in the laboratory. The class IgG is usually associated with autoimmune diseases. Unfortunately, IgG class antibodies are also the main class of antibody seen in normal immune responses. The most useful antibody tests involve introducing the patient's antibodies to samples of his or her own tissue, usually thyroid, stomach, liver, and kidney tissue. If antibodies bind to the "self" tissue, it is diagnostic for an autoimmune disorder. Antibodies from a person without an autoimmune disorder would not react to "self" tissue. Autoimmune disorders ●Systemic lupus erythematosus: A general autoimmune disease in which antibodies attack a number of different tissues. The disease recurs periodically and is seen mainly in young and middle-aged women. ●Rheumatoid arthritis: Occurs when the immune system attacks and destroys the tissues that line bone joints and cartilage. The disease occurs throughout the body, although some joints may be more affected than others. ●Good pasture's syndrome: Occurs when antibodies are deposited in the membranes of both the lung and kidneys, causing both inflammation of kidney glomerulus (glomerulonephritis) and lung bleeding. It is typically a disease of young males. ●Grave's disease: Caused by an antibody that binds to specific cells in the thyroid gland, causing them to make excessive amounts of thyroid hormone. ●Hashimoto's thyroiditis: Caused by an antibody that binds to cells in the thyroid gland. Unlike in Grave's disease, however, this antibody's action results in less thyroid hormone being made. ●Pemphigus vulgaris: A group of autoimmune disorders that affect the skin. ●Myasthenia gravis: A condition in which the immune system attacks a receptor on the surface of muscle cells, preventing the muscle from receiving nerve impulses and resulting in severe muscle weakness. ●Scleroderma: Also called CREST syndrome or progressive systemic sclerosis, scleroderma affects the connective tissue. ●Autoimmune hemolytic anemia: Occurs when the body produces antibodies that coat red blood cells. ●Autoimmune thrombocytopenic purpura: Disorder in which the immune system targets and destroys blood platelets. ●Polymyositis and Dermatomyositis: Immune disorders that affect the neuromuscular system. ●Pernicious anemia: Disorder in which the immune system attacks the lining of the stomach in such a way that the body cannot metabolize vitamin B12. ●Sjögren's syndrome: Occurs when the exocrine glands are attacked by the immune system, resulting in excessive dryness. ●Ankylosing spondylitis: Immune system induced degeneration of the joints and soft tissue of the spine. ●Vasculitis: A group of autoimmune disorders in which the immune system attacks and destroys blood vessels. ●Type I diabetes mellitus: May be caused by an antibody that attacks and destroys the islet cells of the pancreas, which produce insulin. ●Guillain-Barre syndrome: Also called infectious polyneuritis. Often occurring after an infection or an immunization (specifically Swine flu), the disease affects the myelin sheath, which coats nerve cells. It causes progressive muscle weakness and paralysis. ●Multiple sclerosis: An autoimmune disorder that may involve a virus affects the central nervous system, causing loss of coordination and muscle control. Autoimmune diagnostic market Autoimmune disease diagnostics have been vastly undervalued by patients and healthcare practitioners. Now, however, rising awareness of the clinical and financial benefits of autoimmune tests is boosting their deployment. The worldwide autoimmune marketplace is comprised of approximately 30 key manufacturers and over 200 distribution outlets worldwide. Using current growth rate (5-10 per cent) along with historical market data, autoimmune market can be estimated at $220-$240 million. Market is Growing @ 25 per cent for Asia Pacific, North America @ 40 per cent, Europe 25 per cent. Technology split is 60 per cent IFA, 30 per cent EIA, 10 per cent automation. According to the Market Scenario, transition will be towards Immuno Assay Analyzer @ 30 per cent, IFA @ 40 per cent, EIA @ 20 per cent, Manual Luminex @ 5 per cent, Other Alternate Tech (WB) @ 5 per cent. Frost & Sullivan estimates that the total European autoimmune disease diagnostics market was worth USD 440 million in 2004 and is forecast to reach USD 700 million in 2011. Diagnostics for thyroid diseases accounted for over half of overall market revenues in 2004 So far, lack of patient knowledge about autoimmune diseases has been compounded by the limited understanding of healthcare professionals regarding the range and utility of available autoimmune tests. The key challenge for autoimmune testing companies has, therefore, been to develop effective communication channels that emphasis the importance of diagnostic information and the role they play in lowering treatment costs through early diagnosis and intervention. "Promoting the concept of better usage of diagnostic tests resulting in more targeted treatments, better patient care and reduced costs to the healthcare continuum, is set to support uptake," says Dr V. Luxami, Head, Dept of Microbiology, Nizam's institute of Medical Sciences, Hyderabad. "Developing closer relationships with the various patient groups and undertaking pharmacoeconomic studies that highlight the overall clinical and cost benefits of autoimmune diagnostics are also poised to encourage market growth," says Dr Lata Bichelle, consultant rheumatologist, head, Dept of Medicine, Chief - Rheumatology Division , Seth GS Medical College & KEM hospital, Mumbai. New analysis from Frost & Sullivan, US autoimmune disease diagnostics markets, reveals that the market generated revenues of $202.3 million in 2006 and estimates this to reach $326.3 million in 2013, as testing increases for autoimmune diseases. "With medical research suggesting that certain autoimmune diseases are more prevalent than previously believed, companies like Bio-Rad can aggressively pursue the available opportunities." Says Siddharth Puranik , marketing manager, Bio-Rad India. Bio-Rad have a strong presence in the market as it has both EIA and IFA technology available, of which the IFA method is considered a gold standard in India. Another advantage with Bio-Rad is the availability of dedicated PhD Automation. Moreover Bio-Rad is the key manufacturer of Autoimmune diagnostic Kits ,enjoying the world wide Leadership Position. Additionally all of its kits are FDA cleared. "The PhD™ system from Bio-Rad is designed to provide flexibility in autoimmune testing. Each workstation can be changed from EIA to IFA in 30 seconds, and a single computer can control one to 10 workstations, whether each is running EIA or IFA and using micro plates or slides. One work list programmed manually or via bar-code scanner, can accommodate eight EIAs or four IFAs. Today clinical laboratory environment demands the highest level of reliability, efficiency, and accuracy, we have coupled all the three while developing our diagnostics kits - Bruno Larida, marketing manager, Autoimmune Division, Bio-Rad - US. " Our new IFA product line provides our customers with accurate and reliable results in the most critical area of autoimmune testing like vasculitus and intolerance testing ". "As awareness levels rise, autoimmune disease diagnostics is poised to emerge as one of the fastest growing segments in the Indian diagnostics market. A rapidly expanding range of Diagnosing Kits and automated processing platforms are expected to provide momentum to uptake of autoimmune diagnostics" adds divisional manager, Bio-Rad India. (The author is with Bio-Rad Laboratories India Pvt Ltd)

 
[Close]