Antibodies to neurotransmitters - possible biomarkers of Alzheimer's disease and depressive disorders

Background. An important role in the development of technologies for personalized prevention, in particular the search for biomarkers of neuropsychiatric diseases, is played by the study of molecular neuroimmune mechanisms of their development. According to modern data, one of the leading links in the neurochemical mechanisms in their development are disorders of the neurotransmitter systems of the brain. At present, a close relationship has been revealed between the dysfunction of neurotransmitter systems and the induction of autoantibodies to them in various forms of CNS pathology. Objective: to analyze the content of antibodies to dopamine, serotonin and glutamate in the blood sera of patients with AD in comparison with the level of these antibodies in patients with depressive disorders. Materials and Methods. The study was performed on samples of 75 blood sera from women aged 65-85 years with a verified diagnosis of Alzheimer's disease, 32 blood sera from women aged 45-55 years with a verified diagnosis of depressive disorders, and 59 blood sera from apparently healthy women who underwent medical examination. Antibodies to the neurotransmitter’s dopamine, serotonin, and glutamate were determined by solid-phase ELISA. Conjugates of the neurotransmitter with bovine serum albumin (BSA) were used as test antigens. Conjugated antigens of dopamine and serotonin with BSA were synthesized using diazotized protein. Glutamate-BSA conjugate was synthesized using glutaraldehyde. The data obtained were statistically processed using the nonparametric Mann-Whitney test. Results. In the blood sera of patients with Alzheimer's disease, an increased content of autoantibodies to dopamine, serotonin, and glutamate was found compared to their content in control blood sera from apparently healthy women, as well as in blood sera from patients with depressive disorders. The combination of Alzheimer's disease with depressive disorders leads to an increase in the level of autoantibodies to dopamine, serotonin and glutamate in blood serum compared to their content in depressive disorders. Conclusion. The results obtained allow us to consider autoantibodies to dopamine, serotonin and glutamate as neuroimmune markers of Alzheimer's disease.