We present a mathematical study for the development of Multiple Sclerosis in
which a spatio-temporal kinetic model describes, at mesoscopic level, the
dynamics of a high number of interacting agents. We consider both interactions
among different populations of human cells and motion of immune cells,
stimulated by cytokines. Moreover, we reproduce the consumption of myelin
sheath due to anomalously activated lymphocytes and its restoration by
oligodendrocytes. Successively, we fix a small time parameter and assume that
the considered processes occur at different scales. This allows to perform a
formal limit, obtaining macroscopic reaction-diffusion equations for the number
densities with a chemotaxis term. A natural step is then to study the system,
inquiring about the formation of spatial patterns through a Turing instability
analysis of the problem and basing the discussion on microscopic parameters of
the model. In particular, we get spatial patterns oscillating in time that may
reproduce brain lesions characteristic of different phases of the pathology