  I will present predictions from chemical evolution model aimed at a
self-consistent study of both optical (i.e. stellar) and X-ray (i.e.gas)
properties of present-day elliptical galaxies. Detailed cooling and heating
processes in the interstellar medium (ISM) are taken into and allow a reliable
modelling of the SN-driven galactic wind. SNe Ia activity, in fact, may power a
galactic wind lasting for a considerable amount of the galactic lifetime, even
in the case for which the efficiency of energy transfer into the ISM per SN Ia
event is less than unity. The model simultaneously reproduces the
mass-metallicity, the colour-magnitude, the L_X - L_B and the L_X - T
relations, as well as the observed trend of the [Mg/Fe] ratio as a function of
sigma, by adopting the prescriptions of Pipino & Matteucci (2004) for the gas
infall and star formation timescales. The "iron discrepancy", namely the too
high predicted iron abundance in X-ray haloes of ellipticals compared to
observations, can be solved by taking into account the existence of dust. I
will make predictions on several abundance ratios in the ISM and compare them
with the most recent observations.
