Chapter 8 Immune Tests. Immuno diagnostic Studies. Studies antigen-antibody reactions for diagnosis of infectious disease, autoimmune disorders and immune allergies. Also Blood groups and types , tissue graft transplant matching and cellular immunology. Antibodies.
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Studies antigen-antibody reactions for diagnosis of infectious disease, autoimmune disorders and immune allergies.
Also Blood groups and types , tissue graft transplant matching and cellular immunology.
Are proteins produced by the bodies immune system in response to an antigen or antigens. The antigen-antibody response is bodies natural response to invading organisms
Are substances that stimulate and subsequently react with the products of immune response.
They may be enzymes, toxins, microorganisms (bacteria,fungus,virus etc.) tumors or autoimmune factors
Autoantibodies, that is antibodies against self
Exhibit a lack of one or more components of the immune system, which includes B, T lymphocytes, phagocytic cells, and the complement system.
Primary(congenital DiGeorg’s syndrome) and Secondary(AIDS)
Burton’s agammaglobulinemia B cell deficiency (asociated with recurrent bacterial infections after 6 months)
Thymic aplasia (Di george’s syndorme) T cell deficiency (recurrent parasitic,viral and protozoal infections)Chronic Muco-cutaneous candidiasis T cell dysfunction specifically for candida albicans.
Autoantibodies are directed towards nuclear material (ANA’s) or to cytoplasm. Many abnormal antibodies are present with autoimmune (rheumatic) disease.
ANA is a group of protein antibodies that react against cellular nuclear material, it is sensitive for detecting SLE (95%) , but also detected in other rheumatic disorders , therefore it is not specific.
Homogenous pattern Diffuse SLE
Outline pattern SLE
Speckled pattern non-specific
Nuclear pattern Scleroderma, polymyositis
This test is used when autoimmune disease is suspected (particularly systemic lupus erythematosus).
This test can also be performed when a patient has unexplained symptoms such as arthritis, rashes, or chest pain.
Appear is 90% of CREST syndrome (variant of scleroderma)
Scleroderma: Excessive fibrosis and collagen deposition throughout the body, affecting skin , cardiovascular , kidney and GI systems
1-Diffuse scleroderma (skin and viscera)
2-C(calcinosis) R(Raynauds phenomenon) E(esophageal dysmotility) S (sclerodactyly) T(telangiectasia)
common in females, 80% have positive Rheumatoid Factor (anti-IgG Ab)
Classic presentation : morning stiffness improving with use , symmetric joint involvement and systemic symptoms : fever, fatigue, pleuritis, pericarditis.
2-Arthritis in 3 or + joints (PIP-MCP-wrist-elbow-knee-ankle-MTP
3-Arthritis in hand
6-Serum rheumatoid factor
4 of seven criteria . 1-4 for 6 weeks
Loss of bone in periarticular areas
Erosion (loss of bone in margins)
Joint space narrowing
(due to cartilage loss)
The RF test is used mainly in the diagnosis of rheumatoid arthritis, although the test result can be positive in many other diseases as well as in healthy people.
RF is an antibody that attaches to immunoglobulin G (IgG), forming a molecule known as an immune complex. This immune complex can activate various inflammatory processes in the body.
About 80% of patients with rheumatoid arthritis have positive RF tests.
Carcinoembryonic antigen (CEA) is a family of glycoproteins encoded on chromosome 19.
It was first observed in extracts of colonic carcinoma tissue.
Elevated levels are found in serum from patients with a wide variety of tumor types including GI, lung, breast, ovary, and uterus.
CEA is most useful in monitoring patients for tumor recurrence and therapeutic efficacy. Levels will usually fall following successful treatment and remain stable. Rising levels in these patients may indicate recurrence.
The antiphospholipid antibody syndrome (APAS) is currently recognized as a common risk factor for arterial or venous thromboembolic disease.
These antibodies have also been associated with a range of clinical conditions including fetal loss, endocarditis, stroke, heart attack, and hemolytic anemia.
It is a standard practice in most clinical laboratories to measure and report:
both IgG and IgM
antiphospholipid antibody levels.
Anticardiolipin antibodies (aCL) are a heterogeneous group of antibodies (IgG, IgM, and IgA classes). that react with negatively charged phospholipids.
autoantibodies directed against cardiolipin is frequently found in systemic lupus erythematosus (SLE) patients.
Levels of thyroglobulin antibodies in serum can also be useful in the assessment of a number of thyroid disorders. 90 percent of patients withMore than autoimmune thyroiditis (Hashimoto\'s thyroiditis) have thyroglobulin or thyroid microsomal antibodies. While not diagnostic, the detection of thyroglobulin antibodies can aid: 1) in predicting progression of clinical thyroiditis, 2) in further substantiating thyroid disease in patients with non-thyroidal illness, and 3) in predicting postpartum thyroiditis.
levels of TPO antibodies in serum can be useful in the assessment of a number of thyroid disorders. More than 90 percent of patients with autoimmune thyroiditis (Hashimoto\'s thyroiditis) have thyroglobulin or TPO antibodies.
Antibodies to TPO have also been found in most patients with idiopathic hypothyroidism (85%) and Graves\' disease (50%), and less frequently in patients with other thyroid disorders. Low titers may also be found in 5-10 percent of normal individuals.
Antimitochondrial AntibodyPrimarily used when there are symptoms of liver or other organ damage, to confirm a medical diagnosis, or help to identify possible causes of tissue damage.The antimitochondrial antibody test is positive in up to 94% of people with biliary cirrhosis. It is positive in less than 1% of normal people..
Titers (blood levels) of more than 1:160 are generally found only in biliary cirrhosis.Antimitochondrial antibodies are helpful in distinguishing biliary (bile system) cirrhosis from liver problems due to obstruction outside of the liver, viral hepatitis, and alcoholic cirrhosis
Autoimmune liver disease panel (Test)DefinitionAn autoimmune liver disease panel is a series of tests performed when autoimmune liver disease is suspected. These tests include anti-smooth muscle (ASA)antibodies, anti-mitochondrial antibodies(AMA),anti-nuclear antibodies(ANA).
ANTIPARIETAL CELL ANTIBODIESA serologic blood test which measures the presence of antibodies to gastric parietal cells. Less than 2% of the general population will be antibody positive (in the elderly this can be higher).
Approximately 90% of individuals with pernicious anemia will be antibody positive. A positive result may also be seen in atrophic gastritis, gastric ulcer, thyroid disease, iron deficiency anemia, and diabetes.
Antibodies to parietal cells are present in 80% of adults with pernicious anemia and chronic gastritis; they may participate in the early pathogenesis of parietal cell destruction. They are also present in occasional patients with gastric ulcer or gastric cancer With time, the titer of parietal cell antibodies will decline in some patients with pernicious anemia (possibly related to loss of parietal cells) whereas intrinsic factor antibodies persist.
Use Detect the presence of circulating glomerular basement membrane-specific antibodies in Goodpasture syndrome; quantitation may be useful in monitoring treatment.
This test is often used in conjunction with the antineutrophil cytoplasmic antibody (ANCA) test for Wegener granulomatosis and vasculitis.
Pulmonary hemorrages , renal lesions, hemautria,crescentic glomerulonephritis
The glomerular basement membrane of this glomerulus is brightly illuminated in yellow by the anti-GBM antibodies that are bound to it.
Autoantibodies to postsynaptic acetylcholine receptors are responsible for the muscle weakness and fatigabilities of myasthenia gravis. These antibodies are detectable in the serum of 80 - 90 % of patients with generalized myasthenia gravis and in 55 - 70 % of patients with ocular myasthenia.
The receptor antibody titers tend to be higher in females. A good correlation is observed between antibody titers and muscle weakness in individual patients , therefore it is a highly specific and sensitive test for use in the diagnosis and management of myasthenia gravis. Receptor antibody titers tend to rise several weeks before exacerbations in patients with established myasthenia gravis.
ANTI-INSULIN ABIf IgG and IgM antibodies against insulin are elevated, your body reacts as if the insulin is foreign -- this may make insulin less effective or neutralize it. IgG: is the most common type of anti-insulin AB.IgM: may cause insulin resistance(> daily insulin requirement 200U)IgE may be responsible for allergic reactions
Why the test is performedThis test is performed if you are a diabetic and the insulin no longer seems to control your diabetes, or you appear to have an allergic response to the insulin.This test measures your immune system\'s response to insulin and the different types of cells present.
Anti Gliadin Antibody(AGA) is a marker of Celiac disease associated with Gluten-Sensitive Enteropathy or Dermatitis Herpetiformis. Adherence to a gluten-free diet will result in decreased AGA in 2-6 months. AGA is present at the following frequencies: Gluten-Sensitive Enteropathy 90%, Dermatitis Herpetiformis 30%-60%, Crohn\'s Disease 15%, and Atopic Dermatitis 10%. The presence of both IgG and IgA Anti-Gliadin antibody indicates a high probability of Celiac disease.
Antibodies to gliadin (wheat protein) have been shown conclusively to be the toxic agent in celiac disease.
Recently serologic testing has been strongly suggested for screening patients with suspected gluten-sensitive enteropahty as well as for monitoring dietary compliance
The gliadin assay has a sensitivity of 95% for active, untreated celiac patients when both IgG and IgA are used. The test has an overall specificity of 90%
AGA is less sensitive but more specific than IgG Anti-Gliadin antibody (GGA).
ANCA (antineutrophil cytoplasmic Antibodies) –The neutrophil contains two main kinds of granules, the primary (alpha or azurophilic) granules and the secondary (specific) granules. The main azurophilic granule proteins are the enzyme myeloperoxidase (MPO) and the serine proteases, elastase, cathepsin-G, and proteinase 3 (PR3)
proteinase 3 (PR3)
The main antigen associated with the c-ANCA fluorescence pattern is PR3 There is a high correlation between c-ANCA positive sera and antibodies to PR3 in patients with Wegener\'s granulomatosis and other forms of systemic vasculitis, although this is not a 100% correlation. In most cases, binding of the antibody to PR3 results in loss of enzyme activity.
c-ANCA positive sera and antibodies to PR3 in patients with Wegener\'s granulomatosis.p-ANCA (perinuclear pattern of antineutrophil cytoplasmic antibodies) in patients with polyarteritis Nodosa PAN).
PAN= polyarteritis Nodosa