  A new method is developed that permits the simple evaluation of two-loop
response functions for fermions coupled to a gauge field. We employ this method
to study the gauge-invariant response functions in the Algebraic Fermi liquid,
a non-Fermi liquid state proposed to describe the pseudogap phase in the QED3
theory of cuprate superconductors. The staggered spin susceptibility is found
to exhibit a characteristic anomalous dimension exponent \eta_4, while other
correlators show behavior consistent with the conservation laws imposed by the
symmetries of the underlying theory.
