  Let M be an open, connected manifold. A classical theorem of McDuff and Segal
states that the sequence of configuration spaces of n unordered, distinct
points in M is homologically stable with coefficients in Z: in each degree, the
integral homology is eventually independent of n. The purpose of this note is
to prove that this phenomenon also holds for homology with twisted
coefficients. We first define an appropriate notion of finite-degree twisted
coefficient system for configuration spaces and then use a spectral sequence
argument to deduce the result from the untwisted homological stability result
of McDuff and Segal. The result and the methods are generalisations of those of
Betley for the symmetric groups.
