IgG anti Sm
The device SM.CE is an Enzyme ImmunoAssay (ELISA) intended to be used for the quantitative determination of IgG autoantibodies against Sm autoantigens 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 the occurrence of autoantibodies against several nuclear or cytoplasmatic 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 Polymyositis, SLE, MCDT and Sjogren’s Syndrome.
Antibodies direct to Sm (Smith) antigens are present in about 40% of patients with systemic lupus erythematosus (SLE) and they are considered really specific marker for this disease.
Microplates are coated with a preparation of purified Sm antigen. In the 1st incubation, the solid phase is treated with diluted samples and anti-Sm 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-Sm are detected by the addition of anti hIgG antibody, labelled 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 anti-Sm IgG antibodies present in the sample. IgG in the sample may be quantitated by means of a standard curve calibrated in arbitrary units per milliliter (arbU/ml) as no international standard is available.
- Specificity of anti-Sm antibodies by ELISA for systemic lupus erythematosus: increased sensitivity of detection using purified peptide antigens. M Field, D G Williams, P Charles, and R N Maini. Ann Rheum Dis. 1988 October; 47(10): 820–825.
- Development of antigen-specific ELISA for circulating autoantibodies to extracellular matrix protein 1 in lichen sclerosus. Noritaka Oyama1,2,3, Ien Chan1, Sallie M. Neill2, Andrew P. South1, Fenella Wojnarowska4, Yoshio Kawakami3, David D’Cruz5, Kirti Mepani5, Graham J. Hughes5, Balbir S. Bhogal2, Fumio Kaneko3, Martin M. Black2 and John A. McGrath1 . J. Clin. Invest. 113(11): 1550-1559 (2004). doi:10.1172/JCI20373
- Anti-Sm-RNP activity in sera of patients with rheumatic and autoimmune diseases. M. Abu-Shara, M. Krup, H. Slor and Y. Shoenfeld. Clinical Rheumatology. Volume 9, number 3/September 1990.