Mpl isoform evolution in a single patient. (A) Immunoblots after 1-dimensional electrophoresis of patient platelet lysate obtained at diagnosis in May 1997 and again in January 1999 were probed with the Mpl C-terminal antiserum. The immunoblot was reprobed with the glycoprotein IIb antiserum to verify equal protein loading. (B) Two-dimensional gel electrophoresis of the platelet lysates shown in (A) were probed with the C-terminal antiserum.