High-energy Operator Product Expansion is a formalism to study scattering amplitudes at high-energy (Regge limit) in perturbation theory. When it is applied to the product of two electromagnetic currents, we may write the unpolarized DIS amplitude as a convolution of coefficient functions and matrix elements of Wilson lines. The energy dependence of the cross-section is encoded in the Balitsky-Kovchegov evolution equation. To study polarized scattering processes one has to include sub-eikonal corrections into the OPE formalism.
I will discuss the OPE of two electromagnetic currents with sub-eikonal terms: I will present new impact factors, matrix elements of new operators which are parametrized by new quark and gluon distributions, and present new high-energy evolution equations.