  We demonstrate that a quantum spin Hall current, spontaneously generated at
the edge of a two-dimensional topological insulator, acts as a source of
spin-pumping for a magnetic impurity with uniaxial anisotropy. One can then
manipulate the impurity spin direction by means of an electrical current
without using either magnetic electrodes or an external magnetic field.
Furthermore we show that the unique properties of the quantum spin Hall
topological state have profound effects on the inelastic electron tunneling
spectrum of the impurity. For low current densities inelastic spin-flip events
do not contribute to the conductance. As a consequence the conductance steps,
normally appearing at voltages corresponding to the spin excitations, are
completely suppressed. In contrast an intense current leads to spin pumping and
generates a transverse component of the impurity spin. This breaks the
topological phase yielding to the conductance steps.
