  A correct general formula for the spin current through an interacting quantum
dot coupled to ferromagnetic leads with magnetization at an arbitrary angle
$\theta$ is derived within the framework of the Keldysh formalism. Under
asymmetric conditions, the spin current component J_{z} may change sign for
$0<\theta<\pi$. It is shown that the spin current and spin tunneling
magnetoresistance exhibit different angle dependence in the free and Coulomb
blockade regimes. In the latter case, the competition of spin precession and
the spin-valve effect could lead to an anomaly in the angle dependence of the
spin current.
