  We prove that the fluctuations of mesocopic linear statistics for orthogonal
polynomial ensembles are universal in the sense that two measures with
asymptotic recurrence coefficients have the same asymptotic mesoscopic
fluctuations (under an additional assumption on the local regularity of one of
the measures). The convergence rate of the recurrence coefficients determines
the range of scales on which the limiting fluctuations are identical. Our main
tool is an analysis of the Green's function for the associated Jacobi matrices.
As a particular consequence we obtain a Central Limit Theorem for the modified
Jacobi Unitary Ensembles on all mesosopic scales.
