ENA Screening IgG
Enzyme ImmunoAssay (ELISA) for the qualitative determination of IgG auto-antibodies to SSA, SSB, Sm, RNP68, Scl-70, Jo-1, in human plasma and sera.
Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which allows an immune response against its own cells and tissues. Any disease that results from such an aberrant immune response is termed an Autoimmune Disease.
Rheumatoid autoimmune diseases are often associated with auto-antibodies to Nuclear Antigens. We can to distinguish between Anti Nuclear Antibodies (ANA), associate with autoimmune systemic diseases as SLE (Systemic Lupus Erythematosus), RA (Reumatoid Arthritis), Scleroderma, MCDT (Mixed Connective Tissue Disease) and Sjogren’s Syndrome; and Extractable anti Nuclear Antibodies (ENA), associate with autoimmune systemic disease as Polymyositis, SLE, MCDT and Sjogren’s Syndrome.
The serological detection of extractable antinuclear antibodies (ENA) in patient with suspected autoimmune disorders is common practice in every immunological laboratory. When this first diagnostic step is performed with positive results, we can go along with the isolate detection and quantification of the individual antibodies.
Microplates are coated with recombinant antigens SSA52&60KDa, SSB, Sm, RNP68, Scl-70, Jo-1.
In the 1st incubation, the solid phase is treated with diluted samples and ENA IgG are captured, if present, by the solid phase.
After washing out all the other components of the sample, in the 2nd incubation bound anti nuclear IgG are detected by the addition of anti hIgG antibody, labeled with peroxidase (HRP).
The enzyme captured on the solid phase, acting on the substrate/chromogen mixture, generates an optical signal that is proportional to the amount of ENA IgG antibodies present in the sample. The presence of IgG in the sample may therefore be determined by means of a cut-off value able to discriminate between negative and positive samples.
- Int J Pathology. Dec 2007; 5(2):67-71. Pattern of anti-ENA (extractable nuclear antigens) antibodies in different clinical desorders; a clinical laboratory based study. I Siddiqui, J Farooqi, F Ghani, A Habib, DA Shariff.
- Journal of Clinical Pathology. 2001, 54:413; doi:10.1136/jcp. It is useful to test for antibodies to extractable nuclear antigens in the presence of a negative antinuclear antibody on Hep-2 cells? KF Thomson, A Murphy, MJD Goodfield, SA Misbah.
- Modern Medical Laboratory. Vol 31, N°6, Page 495 -499 (2003). Immunity. The measuring method of anti-ENA antibody. Sakai, Hiroshi.
- Annals of the New York Academy of Sciences. 2005, vol. 1050, pp. 327-339. Comparison of different test systems for simultaneous autoantibody detection in connective tissue diseases. P Eissfeller, M Sticherling, D Sholz, K Hennig, T Luttich.