DLI response in three patients (A, B, and C). Results of four different techniques are displayed in parallel relative to time. The shaded areas indicate the critical switch period. DNA-C: DNA chimerism by multiplex PCR ([▪] recipient DNA chimerism; [□] mixed recipient/donor DNA chimerism; [▨] donor DNA chimerism). PCR: qualitative RT-PCR results ([•] positive; [○] negative). QPCR: quantitative RT-PCR results (▴). FISH: fluorescent in situ hybridization ([⧫] absolute granulocyte counts, left Y-axis; [▾] donor granulocytes as a percentage as determined by percentage of CD15⁺ donor cells, right Y-axis); GVHD, onset of GVHD; HU, hydroxyurea treatment; IFN, IFN treatment.