  An argument is made on the existence of a low-temperature itinerant
antiferromagnetic (AF) spin alignment, rather than persistent helical (PH), in
the ground state of a two dimensional electron gas in a semiconductor quantum
well with linear spin-orbit Rashba-Dresselhaus interaction at equal coupling
strengths, $\alpha$. This result is obtained on account of the opposite-spin
single-particle state degeneracy at $\mb k = 0$ that makes the spin instability
possible. A theory of the resulting magnetic phase is formulated within the
Hartree-Fock approximation of the Coulomb interaction. In the AF state the
direction of the fractional polarization is obtained to be aligned along the
displacement vector of the single-particle states.
