Lupus is characterized by a large production of autoantibodies that are directed against membrane antigens, including anti-Ro/SSA. Anti-Ro/SSA antibodies may be found in the blood prior to the other lupus-related autoantibodies.  

According to Ángel Maquieira, researcher at the Universitat Politècnica de València (UPV), belonging to the Institute of Molecular Recognition and Technological Development (IDM), the immunological tests currently used are based on the determination of autoantibodies using the ELISA technique.  These tests are not very sensitive, which limits the determination of extremely low concentrations of antibodies that may be present in the early stages of the disease.

To address this deficiency, researchers from the Universitat Politècnica de València, the Universitat de València and the Hospital Universitari i Politècnic La Fe have developed, on a laboratory scale, new highly sensitive and low-cost biosensors that allow early detection of autoantibodies in very early stages of the disease.  
From a sample of a few microliters of blood or saliva, the system (patented by UPV, UV and HUP La Fe) is able to detect the presence of anti-Ro/SSA antibodies characteristic of each disease.

"The developed biosensor represents a new paradigm within the biosensing industry, because not only do we detect the concentrations of the target antibodies but we can even identify the way in which they interact.  In this way, diagnosis can be made using the mechanistic fingerprints of each disease, while prognosis is achieved by using the concentration of the target antibodies. It is therefore a two-in-one system (diagnosis + prognosis), which ostensibly reduces the number of false positives and negatives. The current biosensors only quantify concentrations", explains David Giménez, professor at the University of Valencia.

At the same time, Maquieira adds: "Each autoimmune disease creates its own anti-Ro/SSA antibodies with a particular fingerprint, and such fingerprints are distinguished by our biosensor.  Furthermore, our detector effectively quantifies anti-Ro/SSA antibodies at very low concentrations, which makes it possible to evaluate the symptomatology presented by the patient extraordinarily early", explains Maquieira.  

As proof of concept, previous assays showed a sensitivity of 1.51 U/ml of autoantibodies, two orders of magnitude more sensitive than current commercial ELISA techniques.

The researchers already have a biosensor that could be used in clinical practice. The last results of the work developed by the researchers of the UPV, the UV and the HUP La Fe have been published in the magazines Biosensors and Bioelectronics and Analytical and Bioanalytical Chemistry.

Doctor José Andrés Román, director of the Clinical Area of Rheumatological Diseases of the Hospital La Fe, points out that the results obtained from comparing this technique to evaluate the symptoms presented by the patients and their activity, in more than 150 patients with lupus and a group of people with a healthy control population, "have confirmed this high sensitivity of the new technique studied".