SECTION 2: IFA KITS

Multiple Test Systems

The utilisation of fluorescent autoimmune antibody screening tests allows the simultaneous detection of circulating nuclear (ANA), mitochondrial (MA), parietal cell (PCA), smooth muscle (SMA) and LKM by indirect immunofluorescence. All necessary tissue substrates are contained in each slide well of this system to perform the above antibody screening.

MITOCHONDRIAL ANTIBODY TEST SYSTEM (MA)

Mitochondrial antibody (MA), a circulating autoantibody in chronic liver disease, is of great clinical importance in differentiating chronic active hepatitis (CAH). It is particularly useful in the diagnosis of primary biliary cirrhosis (PBC). Tests for the detection of mitochondrial antibodies are recommended as an alternative to surgical exploration as the presence of high titre MA can provide confirmatory evidence for the diagnosis of PBC. Both CAH and PBC have many overlapping immunological features and may represent a continuum of single disease entity. MA titres in PBC do not appear to have any correlation with clinical activity since they do not vary with the severity of progression of the disease and cannot serve as a monitor of response to therapy or provide prognostic information. MA are present in sera of patients with a variety of liver disorders but are only present in high titres in the majority of patients with PBC. The detection of MA by the indirect immunofluorescent technique is most useful in differential diagnosis of extra hepatic obstruction. Rat or mouse kidney substrates and HEp-2 cells are utilised for MA.

ANTI-PARIETAL CELL ANTIBODY TEST SYSTEM (PCA)

Gastric autoimmune disease has been classified into Type A and Type B gastritis based on the morphological changes of the fundus and antral portion of the stomach. Patients with antibodies to parietal cells (PCA) or intrinsic factor (or both) have atrophy of the fundal mucosa (type A) and a very high rate of pernicious anaemia, often associated with other autoimmune endocrine disorders. A positive PCA in the presence of a megaloblastic anaemia makes pernicious anaemia or other autoimmune endocrine disorders likely. The incidence of PCA in patients with pernicious anaemia is 39%. Conditions other than pernicious anaemia may give positive PCA results.

ANTI-SMOOTH MUSCLE ANTIBODY TEST SYSTEM (SMA)

Smooth muscle antibodies can be demonstrated in patients with acute and chronic hepatitis, the highest titres occurring in chronic active hepatitis (CAH). All of the various forms of chronic liver disease show SMA titres less than 1:160, except for CAH where titres up to 1:1280 are found. The differential diagnosis of CAH in patients with chronic liver disease is facilitated by titration of SMA using indirect immunofluorescence method with rat or mouse stomach mascularis mucosa. SMA test have been found helpful in confirming the diagnosis of approximately 70% of cases of CAH. A positive SMA test rules out Systemic Lupus Erythematosus since the SMA test is generally negative in SLE. It is also found in approximately 50% of patients with primary biliary cirrhosis (PBC) and in up to 28% of patients with cryptogenic cirrhosis. High incidences of SMA have also been reported in serum of patients with infective mononucleosis. Diseases including carcinoma of the breast, malignant melanoma and ovarian carcinoma have been reported to contain SMA. Rat or mouse stomach is utilised for the SMA detection in this test system.

SMA testing on HEp-2 substrates aids in differentiation of SMA antibodies such as actin, desmin, vimentin and reticulin.

LIVER / KIDNEY MICROSOMAL ANTIBODIES (LKM)

The LKM antibody is quite rare but can be seen in patents with various types of hepatitis. The antibodies are usually found in autoimmune chronic active hepatitis and viral hepatitis. The diseases can be divided into groups depending on the IFA pattern. The antibodies give different staining patterns on the tissue block but all stain the liver and the proximal renal tubes of the kidney.

CARDIAC MUSCLE ANTIBODY (CMA) TEST SYSTEM

Demonstration of cardiac muscle antibody (CMA) by indirect immunofluorescence antibody method enables assessment and possible detection of cardiac disease. The presence of a (histologically defined) circulating antibody to one or more of the cardiac muscle antigens can aid in the patient diagnosis and prognosis of such diseases as rheumatic fever, myocardial infarction and a variety of post cardiotomy states.

ANCA KITS

Standard IFA methods allow the observation of several different patterns. Two patterns that have been well defined are C-ANCA (Cytoplasm) and P-ANCA (Perinuclear). The C-ANCA pattern shows an uneven granular staining of the cytoplasm. The P-ANCA has a perinuclear/nuclear staining pattern. During the 2nd International ANCA Workshop, it was agreed that these two different patterns should be used to subclassify the antibodies.

ANTI-ADRENAL ANTIBODY TEST SYSTEM

Adrenal antibodies are against particular components of the cytoplasm producing a granular pattern on IFA. These patients are predominantly microsomal but may also be mitochondrial in adrenal sections. They are precipitins, can fix complement and can be demonstrated by IFA. Adrenal Antibody is associated with the idiopathic form of Addison's disease and is more common in males than females. The antibody tends to persist for years following medical treatment. A very low incidence of AD antibody is found in the normal population and as well as in other autoimmune diseases, such as ovarian failure. Patients with idiopathic Addison's disease are prone to a variety of other autoimmune disorders.

ANTI-GLOMERULAR BASEMENT MEMBRANE TEST SYSTEM

Demonstration of Glomerular Basement membrane antibodies (GBM) by primate kidney IFA may enable serological assessment and possible detection of kidney disease. The presence of histologically defined circulating antibody to the glomerular basement membrane can aid in the patient diagnosis and possible prognosis of Goodpasture's syndrome. A linear fluorescence along the Glomerular Basement Membrane can be observed in most Goodpasture's patients. A rapid and quantitative ELISA method and QuickCard are also available for GBM detection.

ISLET CELL ANTIBODY (ICA) TEST SYSTEM

Islet cell antibodies have been associated with a group of 'autoimmune' endocrine disorders, more specifically with insulin dependent diabetes. An organ-specific autoimmunity, characterised by the presence of antibodies in patients, can be detected years before the onset of clinical symptoms. These antibodies are useful monitors well before metabolic testing can detect hormonal deficiencies. The situation becomes far more complex in the case of 'stimulating' antibodies that produce hormonal excess and hormonal receptor antibodies. Patients with autoimmune thyroiditis, adrenalitis or gastritis have an increased risk of developing insulin dependent diabetes at any age. Overlapping of antibodies is one of the most important features in this group of disorders, the extreme being 'polyendocrine' syndromes where all the endocrine glands may be involved in the same patient. Since the discovery of the islet cell antibodies in insulin dependent diabetes (IDDM), there has been a growing interest in their significance.

ANTI-OVARY & ANTI-SPERM ANTIBODY TEST SYSTEM

Ovarian and testicular antibodies are found in cases of dysfunction and are common in idiopathic Addison's disease. In the ovary, the antigen is found in the theca cells of the corpus luteum. In the testes, the antigen can be either components of testicular structure or sperm. Anti-leydig cell antibodies are observed in steroid defects.

ANTI-SKIN ANTIBODY TEST SYSTEM (ASA)

The detection of skin antibodies by IFA technique has been established as an aid in the diagnosis of skin and systemic diseases. Monkey oesophagus is utilised for the detection of both basement membrane and intercellular substance antibodies. Intercellular substance antibody has been associated with a variety of pemphigus autoimmune disorders of the skin. The detection of the basement membrane antibody has been associated with the presence of a variety of bullous pemphigoid autoimmune disorders.

ANTI-ENDOMYSIAL ANTIBODY TEST SYSTEM

The detection of anti-endomysial antibodies is an established screening method for coeliac disease. Endomysial IgA antibodies react with the reticulin component of the endomysium of the smooth muscle in primate oesophagus tissue. These antibodies can be found in a high proportion of patients with dermatitis herpetiformis on a non-restricted diet and in almost all patients with coeliac disease and gluten-sensitivity enteropathy with partial or subtotalling villous atrophy.

ANTI-STRIATED MUSCLE ANTIBODY TEST SYSTEM

Substrate: primate striated muscle. Antibodies to both skeletal (voluntary) muscle, and cardiac muscle (myocardium) appear as striped or striated staining on longitudinal muscle fibres. In myasthenia gravis, the antibody is a muscle binding, complement fixing IgG. Two types of reactivity are found, one is organ specific(s), the other non-specific (SH) reacting with both skeletal and heart muscle and are non-complement fixing.

ANTI-SUBMAXILLARY ANTIBODY TEST SYSTEM

In Sjögren's Syndrome, antibodies to salivary duct can be detected with primate salivary tissue substrates. This syndrome also involves the salivary and lacrimal glands. It is a chronic inflammatory disease with widespread manifestations with one of the connective tissue diseases often present. Sjögren's is characterised by a dryness of the mouth and eyes, frequently involving the respiratory tract, ears and vaginal mucosa (i.e. mucosa membranes) and with a higher incidence in women. Antibodies are often found, but are not necessarily a factor in pathogenesis of the disease.