Multiple sclerosis is a severe, incurable disease of the nervous system, in which pathogenic antibodies begin to attack the myelin sheath of nerve cells. It is responsible for the integrity of nerve cells and effectiveness of the signal flow through the nerve endings. Violation of this process can lead to various consequences ranging from mild numbness to paralysis and blindness. The destruction of myelin proceeds gradually, consequently, the disease does not manifest itself for a long time, doing so most often at the age of 15-40.
      Early diagnosis and timely treatment can slow the disease development and improve the patient's life. At present, the methods for determining multiple sclerosis are complicated and not always available. Magnetic resonance tomography and cerebrospinal fluid analysis which are currently used to identify and confirm the diagnosis, are expensive, complicated, and time-consuming.
      Scientists of the Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences in collaboration with colleagues from the Institute of Fundamental Medicine and Chemical Biology of the Siberian Branch of the Russian Academy of Sciences and V.F. Voyno-Yasenetsky Krasnoyarsk State Medical University suggested identifying multiple sclerosis using RNA aptamers and bioluminescent proteins. The disease can be diagnosed by performing a blood test, which makes this method easy, fast, inexpensive and available.
     Aptamers are the laboratory-synthesized DNA or RNA molecules capable of recognizing and combining with specific target molecules. In this analysis, the target is represented by pathogenic autoantibodies that attack the myelin. When an aptamer finds a target cell in the patient's blood, it binds with it. As it is, the complex of the bound aptamer and target does not manifest itself. To identify the resulting complexes, it was proposed to preliminarily “label” (tag?) the aptamer with a bioluminescent protein -  obelin, which is able to glow. If the target was not detected, no glowing occurs.
     The study was carried out on 177 blood samples of healthy and ill people with a confirmed diagnosis. The fusion of the aptamer and bioluminescent protein allows the molecules to be more sensitive to the target and to detect it faster. Recognition of healthy patients with negative indicators is performed with the accuracy of 96% while the probability that patients with positive results actually have the disease is 52%. The test does not allow one to distinguish the stages of the disease.
     “We believe that in the future, further improvements of the method will make it be possible to recognize multiple sclerosis, monitor the disease course and evaluate the effectiveness of the treatment. Currently, complicated and expensive methods are used for this purpose. In contrast, blood tests are much simpler, faster and less expensive. MRT, of course, will remain the main method of diagnosis, we are not going to replace it. Our analysis will be a convenient additional tool, suitable for a wide primary examination of patients, ”says Vasilisa Krasitskaya, Candidate of Biological Sciences, research associate at the Institute of Biophysics, KSC SB RAS.
      The study was conducted with the support of the Russian Foundation for Basic Research.