Antibodies directed against native deoxyribonucleic acid (nDNA) were first detected in the serum of patients with systemic lupus erythamatosus (SLE) in the late 1950’s. The presence of anti-nDNA autoantibodies is one of the four highly specific serological markers included in the 1982 American College of Rheumatology revised criteria for the classification of SLE. The detection of elevated levels of anti-nDNA antibodies and decreased serum levels of complement component C3 have been found to be 100% specific for SLE.

High levels of autoantibodies to nDNA are universally regarded as disease specific markers for SLE. In most cases their level is proportional to the clinical disease activity. Early recognition is vital coupled with early treatment. In these cases, drug combinations can lower the anti-nDNA level thereby avoiding long-term risks such as renal and central nervous system involvement.

The two most common methods for detecting anti-nDNA antibodies is indirect immunofluoresence (IFA) and enzyme-linked immunosorbent assays (ELISA).

Both IFA and ELISA products are available, please select the option that best suits your laboratory.

The assay is available in two differing formats, these are MELISA™ and AUTOZYME™. Both formats are based on the sandwich ELISA principle and are:

• calibrated to World Health Organisation standard WO/80.
• show no cross reaction with ssDNA, histones or RF.
• Acuracy, reproducability and specificity.
• Sensitive and fully quantitative for both IgG and IgM antibodies.

MELISA™ stands for Micropin Enzyme-Linked Immunosorbent Assay. In contrast with conventional ELISA technology in which the immunological reaction takes place on the surface of microwells, MELISA™ uses a transferable solid phase system – micropins. All reaction steps are performed in separate microwells. The immunological reaction and the enzyme substrate reaction occur on the surface of the micropin. Thus, incubations are simultaneous and as a result there is no possibility of "drift".

This assay has been designed for the modern laboratory with flexibility in mind. It can be used in manual mode or with automated instrument systems. The AUTOZYME™ system employs ready-to-use colour coded reagents resulting in less "hands on" time. Break-a-well strips ensure flexibility and economic use for any batch size so that patient turn around time can be speeded up. Kit controls coupled with high purity antigens ensure the method is valid and specific.