B cells in the peripheral blood in Parkinson's disease. Clinical and experimental data

Chronic inflammation is found to play a key role in the pathogenesis of Parkinson's disease that is associated with alterations in the composition of peripheral immunocompetent cells. At present CD19+В cells, which are known to be involved in adaptive immune responses and the development of multiple CNS disorders, generate a growing interest. However, studies on B cell changes in PD are lacking and produce conflicting results. The aim of the study is to analyze the content of B cells and their subpopulation of CD19+CD25+ В regulatory cells (В-regs) in the peripheral blood of patients with PD and in transgenic А53Т mice with a-synucleinopathy. Verification of idiopathic form of PD and its stage is performed according to the UK Parkinson’s Disease Society Brain Bank Clinical Diagnostic Criteria and Modified Hoehn and Yahr Scale of disease stages. A53T mice with overexpression of the mutant form of human a-synuclein are used as an experimental model of PD with WT mice served as a control. B-lymphocytes and В-regs are determined by flow cytometry using labeled monoclonal antibodies. There are no differences in the blood content of CD19+ B cells between the total group of PD patients (men and women) and healthy subjects, while their number in women is higher than in men. The content of CD19+CD25+ В-regs is increased in patients in the total group in comparison with healthy subjects and depends on the stage of the disease with the most significant increase found in patients at stage III. In 10-month-old A53T mice, showing PD signs, the number of both CD19+ B cells and CD19+CD25+ B-regs in peripheral blood does not differ from that of WT mice. Thus, our data indicate that while the levels of B cells in PD patients remain unchanged, the content of their subpopulation of B-regs increases with PD progression. It is suggested that B-regs, which produce anti-inflammatory cytokines, are involved in the neuroprotective mechanisms during development of PD.