[Leptomeningeal B-cell follicles in multiple sclerosis: a role in the pathogenesis and prognostic value]

B-lymphocytes play an important role in the development and maintenance of the inflammatory process in multiple sclerosis. Recently special attention has been paid to cell formations that are found in the meninges in patients with multiple sclerosis - the so-called leptomeningeal follicle-like structures that contain not only B-lymphocytes, but also other immunocompetent cells, creating a special environment for clonal expansion, selection and further proliferation of B-lymphocytes. Magnetic resonance imaging (MRI) of the brain with gadolinium-based contrast agents reveals local subarachnoid space contrasting that corresponds to the accumulation of the contrast agent by large lymphoid follicles. This phenomenon is called leptomeningeal contrast enhancement and according to some literature data, its severity correlates with the rate of progression of the disease and functional disability. The review presents the available literature on leptomeningeal follicle-like B-cell structures, as well as prospects of using leptomeningeal contrast enhancement on MRI as a potential biomarker for predicting disease severity in patients with multiple sclerosis.