  We demonstrate that theoretical predictions using current resummation
techniques for the lepton pair production (LPP) rapidity and $x_F$
distributions can be inconsistent with data in high rapidity and $x_F$
kinematic regions by observing their effect in global fits of parton
distribution functions (PDFs). We present an enhanced resummation technique for
the LPP rapidity and $x_F$ distributions that agrees with LPP data. The
enhanced resummation method is used in conjunction with threshold resummation
in deep inelastic scattering (DIS) to perform two global fits of PDFs using the
minimal and Borel prescriptions. The results are analyzed to determine the
effect of threshold resummation on global fits of PDFs.
