The United States Biological Extractable Nuclear Antigen, Human, IgG, BioAssay ELISA Kit is designed to detect IgG class antibodies to Jo-1, Sm, Sm/RNP, SSA(Ro), SSB(La), and Scl-70 in human serum. Wells of plastic microwell strips are sensitized by passive absorption with immobilized antigens. In recent years it has become clear that autoantibodies to a number of nuclear constituents have proven to be useful in the diagnosis of various connective tissue diseases. The Jo-1 autoantibody is one of a family of characteristic autoantibodies seen in myositis patients. They are all specifically found in patients with myositis, and are all associated with a high incidence of accompanying interstitial lung disease. Antibodies directed against the Sm marker are highly specific for patients with SLE and are considered a diagnostic criterion for SLE. The presence of high level RNP antibodies alone are considered diagnostic of mixed connective tissue disease (MCTD) and are usually associated with a more benign disease course, while patients with low levels of RNP antibodies, together with other autoantibodies, may be observed in the serum of patients with progressive systemic sclerosis, Sjögren's Syndrome, and rheumatoid arthritis. The presence of RNP antibodies in the serum of SLE patients is usually associated with a lower incidence of renal involvement and a more benign disease course. To the contrary, patients with Sm antibodies experience a higher frequency of renal and central nervous system complications. Autoantibodies directed against SSA and SSB may be observed in patients with SLE and Sjögren's disease. SSA antibodies are frequently present in the serum of ANA negative SLE patients, such as subacute cutaneous lupus erythematosus, a lupus-like syndrome associated with a homozygous C2 deficiency, and in a subset of patients who lack anti-dsDNA antibodies. Scl-70 antibodies are highly specific for scleroderma. They are also observed in a minority of SLE patients. Scl-70 positive scleroderma patients tend to have a more severe disease course, more internal organ involvement and diffuse rather than limited skin involvement. Scl-70 antibodies are rarely found in other autoimmune diseases, and thus, their detection in a patient with the recent onset of Raynaud's phenomenon is highly significant. The relative frequency of these autoantibodies in association with SLE and other connective tissue diseases either singly, or as multiple autoantibodies, requires an autoantibody profile assessment of each patient's serum in order to obtain the highest degree of clinical relevance in the laboratory workup of these types of patients. Until recently, autoantibodies were tested individually by indirect immunofluorescence, Ouchterlony gel diffusion, hemagglutination, radioimmunoassay, or ELISA. Although the exact etiology of autoimmune diseases is unknown, and the specific role played by autoantibodies in the onset of various autoimmune connective tissue diseases is obscure, the association and frequency of detection of these antibodies, particularly those of the IgG class, by the Extractable Nuclear Antigen, Human, IgG, BioAssay ELISA Kit, offers an efficient test procedure for the research of various connective tissue diseases. Kit Components: 1. Microtiter Plate: 1X96wells2. IgGy, Goat x human (HRP): 1X15ml3. Positive control: 1X350ul4. Calibrator: 1X500ul5. Negative Control: 1X350ul6. Sample Diluent: 1X30ml7. Tetramethylbenzidine (TMB): 1x15ml8. Stop Solution:1X15ml (1N H2SO4)9. Wash Buffer, 10X: 1X100ml Storage and Stability:Store all components at 4°C. Stable for 6 months. For maximum recovery of product, centrifuge the original vial prior to removing the cap.