From pros and anatithemai; to lay up in addition, i.e. (middle voice and figuratively) to impart or (by implication) to consult -- in conference add, confer.
KJV: But of these who seemed to be somewhat, (whatsoever they were, it maketh no matter to me: God accepteth no man's person:) for they who seemed to be somewhat in conference added nothing to me:
NASB: But from those who were of high reputation (what they were makes no difference to me; God shows no partiality)-- well, those who were of reputation contributed nothing to me.