ENA Screen:
Why ENA - Screen Test?
CLINICAL INFORMATION
Connective tissues (collagen-rich tissue eg skin) are found throughout the body, which is composed of cells, rigid fibers like collagen and elastic fibers. Its function is to envelop (eg. Liver, kidney etc) and it separates as well as protects them from other body tissues (i.e strengthens joints, tendons, ligaments also supports smaller blood vessels etc). The immune system is responsible for defending the body against foreign cells - like harmful micro-organisms. But, Autoimmune diseases may be caused when those when antibodies are rarely, by mistake are mis-read as foreign (against self-antigens) and antibodies attacks of our healthy body cells. Extractable Nuclear Antigens (ENAs) are over hundreds of different soluble cytoplasmic and nuclear antigens, hence collectively called as Extractable Antigens. The term ‘Extractable’ means that they can be detached from the cell nuclei using saline (Saline-Extracted Antigens). For example, there six main proteins such as - Ro, La, Sm, RNP, Scl-70 (also called as Anti-Topoisomerase), Jo1 (to name a few). But Anti-ENA Antibodies Panel also include tests for Chromatin, Centromere, Histone (Anti-Histone antibodies are associated with drug-induced type of SLE), and moreover Anti-Histone antibodies are also found in celiac disease ie has auto-antibodies known as ‘Endomysial Antibodies’, (that attack healthy cells i.e inner lining of the intestines causing irritation and swelling) in the blood towards Gluten (where immune system responds abnormally against Gluten protein), hence known as Celiac Disease (auto-immune disease), RNA Polymerase-III etc, for the presence of auto-antibodies. Most ENAs are part of Spliceosomes or Complexes of Nucleosomes – and are a type of small Nuclear Ribo-Nucleoprotein (SnRNPs). These ENAs are usually associated with RNAs and proteins (i.e for eg Polymerases Enzymes). Examples of some diseases are Sjogren syndrome (where it shows the presence of Anti-SSB Antibodies or also called Anti-La and/or Anti SSA Antibodies or also called as Anti-Ro), Systemic Lupus Erythematosis (SLE) – which shows the presence of Anti-SM antibodies, MCTD – Mixed Connective Tissue Disease is associated with Anti-RNP, Scleroderma – associated with Anti-Scl70, polymyositis or dermatomyositis. Therefore ENA (Extractable Nuclear Antigens) panel test, aims for the presence of all those autoantibodies in the blood, generally performed along with Anti-Nuclear Antibody (ANAs occur in both systemic and organ-specific autoimmune diseases) Test (is always performed in conjunction with Clinical Examination), when suspected patients exhibit symptoms of autoimmune disorders associated with connective tissues and also in prognosis (to monitor the progression of disease in confirmed patients) and moreover to distinguish between autoimmune disorders. Additional tests for second-order testing are ordered for more supporting evidence (in overlapping clinical manifestations or test results) to arrive at a definitive diagnosis).Therefore ENA (Extractable Nuclear Antigens) screening test, aims for the presence of all those autoantibodies in the blood, generally performed along with Anti-Nuclear Antibody (ANAs occur in both systemic and organ-specific autoimmune diseases) Test (is always performed in conjunction with Clinical Examination), when suspected patients exhibit symptoms of autoimmune disorders associated with connective tissues and also in prognosis (to monitor the progression of disease in confirmed patients) and moreover to distinguish between autoimmune disorders (additional tests for second-order testing is ordered for more supporting evidence (in overlapping clinical manifestations or test results) to arrive at definitive diagnosis). Examples of few Auto-Antibodies belonging to- ENA Panel tests include Anti-RNP Test also known (in reporting name as) Anti-U(1)RNP or Anti-Ribo-nucleoprotein Test, Anti-Sm Test also known (in reporting name as) Smith Antibody, Anti-SSA /Ro Test also known (in reporting name as) Anti-Sjogren Syndrome-A, Anti-SSB /La Test also known (in reporting name as) Anti-Sjogren Syndrome-B, Anti Scl-70 Test also known (in reporting name as) Scleroderma Antibodies or Anti-Topoisomerase, and Anti Jo-1 Test also known (in reporting name as) Anti-Histidyl Transfer RNA Synthase Antibodies (Anti-Jo 1is associated with autoimmune patients associated to myositis). Hence this test helps in the diagnosis of Autoimmune Connective Tissue Disorders (CTDs). Clinical Manifestations (Signs and Symptoms of Autoimmune disorder include – Fever, persistent fatigue, Muscle Pain, Pain and swelling in the joints, Skin rash, hair loss or loss of scalp hair, Sensitivity to UV light, Raynaud phenomenon, protein in urine, hemolytic anemia (low RBC Count), Leukopenia (low WBC Count) and Neurologic symptoms such as seizures, depression, psychoses etc. Additions tests include IFA, EIA, double immuno-diffusion (Ouchterlony – immuno-blotting), counter immuno-electrophoresis. Other tests include passive hemagglutination, ELISA, Western blotting etc, can be used to identify ENAs and its association with specific autoimmune diseases. Other associated similar autoimmune antibodies are Anti-Nuclear Antibodies – PBC (Anti-gp210, Anti-p62, Anti-sp100), Anti-dsDNA. Anti-Mitochondrial Antibodies (Anti Cardiolipin), Anti-Cytoplasm Antibodies (Anti-Neutrophil Cytoplasmic: C– ANCA, P– ANCA) and Anti-Smooth Muscle (Anti-Actin), as well as Anti-TPO, also called Anti-microsomal, Anti-Cell Membrane (Anti-Ganglioside, Anti-GBM, Anti-Glutamate etc), Anti-Extra Cellular (Anti-thrombin, Lupus Coagulant, Coeliac disease (Anti-Transaminase , Anti-Gliadin), RA (Rheumatoid Factor – Anti-Citrullinated Peptide), Antibodies against Multiple locations (Anti-Phospholipid, Anti- Apolipoprotein etc).
General Instructions:
Sample Requirement: Specimen – As guided by the physician. Test Preparation: None.
NOTE - Sample for specimen collections may vary based on the patient’s condition/cases according to the patient’s presenting complaints/signs or symptoms:
SPECIMEN REQUIREMENT (Special or Rare Cases) - As instructed and guided by Physician / Clinician / Pathologist / as per Laboratory’s requirements, according to procedures and protocols.
This Multi-Specialty Clinical Referral Laboratory RTDIAGNOSTICS provides precise and accurate tests with an extensive range of testing services to the medical centres to help in the diagnosis and identification of pathology in the test specimens for infectious diseases and also to evaluate the function of organ systems of the patient. It prevents further complications and helps to stabilize and restore health to near normalcy at the earliest without delay.
