Autoimmune, SLE Test, Systemic Lupus Erythematosus Testing, ANA testing, Autoantibody Testing
Question 1. What is autoimmune antibody testing?
Autoimmune antibody testing is performed on blood samples to screen for evidence of autoimmune disorders or diseases of immune system. Hundreds of different autoimmune antibodies (autoantibodies) have been described but not all of them are involved in disease. Auto-antibodies are classified into two broad categories; those directed to one tissue/cell type (organ-specific) and those reacting to multiple tissue types (non-specific) or may be produced in response to the disease initiated by another event or cause. In either case, these autoantibodies can be measured as an indicator of a particularly autoimmune disease process. Auto-antibodies are either cause of the disease and carry out the damage that a patient develops.
Question 2. What are autoimmune diseases?
Autoimmune diseases are illnesses in which the immune system produces antibodies (auto-antibodies) and specific white cells (lymphocytes) to attack the body's own cells or tissues as though they were harmful foreign substances. Auto-antibodies, hence autoimmune immune diseases affect a single organ (organ specific) or may be more widespread (systemic) destroying multiple organ systems (organ non-specific) at the same time. In both, auto-antibodies are produced in response to injury, inflammation, or other stimulus. Examples include those breaking down red cells (autoimmune haemolytic anaemia), destroying pancreatic cells (type I diabetes mellitus), and causing muscle damage (myasthenia gravis) and affecting all organ system (rheumatoid arthritis & systemic lupus erythematous, SLE).
Question 3. What are the symptoms of autoimmune Diseases?
Autoimmune diseases are generally difficult to diagnose. Individuals can exhibit very different symptoms; yet have the same underlying disease. Patients present with variety of different complaints at different times and for health workers, this can be a nightmare. Patients often visit many different doctors or clinics and correct diagnosis may take months or even years to be known. Knowledge and awareness on the part of the doctor and effective communication between doctor and patient, including a complete and accurate medical history, together with a thorough physical examination and carefully chosen laboratory tests, are essential to the process.
Below are some of the symptoms that may be associated with autoimmune diseases. If you have combinations of any of these symptoms underlying autoimmune disease process should be suspected and you should be appropriately investigated.
Joint pain and swelling (usually multiple joint involvements)
Skin rash/redness especially over the face (butterfly rash)
Easy sun-burn/photosensitivity
Chronic/recurrent dry /red eyes
Headache, fever, and vomiting
Pallor/Anaemia of unknown cause
Psychosis/Fitting for unknown reason
Fatigue and weight loss for unknown reasons
Thickening /tightness of skin
Kidney failure without a known cause
Passing Dark urine with Anaemia
Painful tips of fingers or toes
Pain or numbness or tingling fingers/toes on exposure to cold
Multiple muscle pains or tender or soreness all over body
Sharp chest wall pain
recurrent miscarriage/foetal death/abortion
Menstrual problems
Chronic Abdominal pain
Chronic Diarrhoea
Easy bruising/Bleeding tendency
Questions 4. How is the test performed?
For all autoimmune disease tests, a blood sample is required, usually taken from a vein on the back of the hand or the inside of the elbow via venepuncture. The nurse or phlebotomist collecting the sample should observe universal precautions for the prevention of transmission of blood-borne pathogens. Generally, blood samples that are grossly haemolysed or lipemic are unacceptable.
Autoimmune antibody tests are done on more advanced testing platform as ELISA machine or an expensive immunochemistry analyser. This testing service as of December 2020 isn’t readily available in almost all hospitals in PNG.
Question 5. How is the tests interpreted?
The test results should be interpreted by experienced doctor. Below are some general guide to autoimmune antibodies (autoantibodies) and commonly associated diseases.
Factor Rheumatoid (RF)–nonspecific elevated in rheumatoid arthritis, SLE, chronic infections, connective tissue diseases and many autoimmune diseases.
Anti-Nucleic Antibody (ANA) - non-specific tests raised in all patients with autoimmune diseases (SLE, RA, and vasculitis)
Anti-double stranded DNA Antibodies (anti-dsDNA)–Raised in SLE
Anti-neutrophilic Cytoplasmic Antibodies (ANCA)- Raised in autoimmune vessel inflammation (vasculitis ) such as Wegener’s granulomatosis, polyarteritis nodosa and a type of kidney inflammation (crescent glomerulonephritis)
Perinuclear anti-neutrophilic cytoplasmic antibodies (pANCA) - Inflammatory Bowel Disease /Ulcerative colitis
Cyclic Citrullinated Peptide (CCP) antibodies– Specific tests for rheumatoid joint disease /arthritis and raised in 70% of patients
Anti-mitochondrial Antibodies –Autoimmune liver disease/primary biliary liver disease/liver failure
Anti-phospholipid Antibodies/ Cardiolipin Antibodies– Autoimmune disease causing recurrent abortions/thrombus
Thyroid antibodies (TSI, Anti-thyroglobulin, & anti-peroxidase) – Autoimmune thyroid diseases/Graves’s Disease/Hashimoto’s
Insulin Antibodies –Elevated in Type I Diabetes Mellitus
Cryoglobulin Tests and Cold Agglutinin Test—autoimmune diseases causing symptoms with cold temperature/Raynaud’s phenomenon/hemolysis)
Anti-nuclear Antibodies Test:
More than 95% of people with SLE have a positive ANA test. However, this test is also raised /positive in few other autoimmune diseases and used as an initial screening test for autoimmune diseases. For example, ANA is also positive in scleroderma (60%), Sjögren's disease (50%), and rheumatoid arthritis (25%). When ANA is positive a more specific tests should be requested. Positive tests for anti-double stranded (ds) DNA or anti-Sm (Smith's) antibodies are definitive for SLE. Identification of anti-RNPs is positive for mixed connective tissue disease (MCTD) as well as SLE
Anti-mitochondrial Antibody Test-
Positive in 94% of patients with primary biliary cirrhosis.
Anti-phospholipid Antibody Test (APLA)-
Prevalence of APLA in SLE patients is 40%. Positive APLA is also seen in over 75% of patients presenting with spontaneous abortions.
Cold Agglutinins Test
Increase is associated with autoimmune haemolytic anaemia, mycoplasma pneumoniae infections (60%) and EBV infections.
Rheumatoid Factor Test
Normal Rheumatoid Factor titre for adults is < 1:80. A positive test may result with chronic hepatitis, chronic viral infection, dermatomyositis, infectious mononucleosis, leukemia, rheumatoid arthritis, scleroderma, or SLE. Adult Still's disease, chronic infection, juvenile rheumatoid arthritis, nephrotic syndrome, and Sjögren's syndrome may also give positive results.
Question 6. Is the test available in PNG?
No. Currently tests can only be done overseas. However, you can arrange for the test through any private hospitals in major towns. In Port Moresby, Port Moresby International Hospital does assist patients sending tests overseas so enquire at their reception.
Questions 7. What is the cost of requesting these tests?
Cost generally depends on type of antibody requested for the suspected autoimmune disease. In general tests cost should be less than K500 to send to Australia.
Question 8. Can medicines interfere with autoimmune Tests?
Yes. Certain drugs, including antibiotics, oral contraceptives, procainamide, tranquilizers, steroids, thiazide diuretics, and some antihypertensive drugs give a false positive result in the ANA test, and the patient should be advised to stop taking these before the test. For the anti-mitochondrial antibody and cryoglobulin tests, fasting for six hours or overnight before the test may be required. No special preparations or diet changes are required for the anti-phospholipid, Cold Agglutinin, or Rheumatoid Factor Tests.
Question 9. What is the treatment for autoimmune Disease?
Always get expert help for assistance on treatment. The aim of treatment is (1) to relief symptoms such as pain, swelling, skin rash etc., by using pain-killers (paracetamol) and anti-inflammatory drugs (ibuprofen, steroid creams) and (2) to specifically cure underlying autoimmune disease with specific drug regimens. Some of these drug combinations may include steroids (prednisolone) and strong immune suppressive agents (hydroxychloroquine, methotrexate). Treatment is usually long term and you will have regular follow-up and blood checks to monitor response as well as emergence of complications early.
