At the time of buccal sampling no signs of mucositis or oral GvHD were present (except where noted). At the time of buccal sampling all patients revealed complete donor chimerism in blood (blood chemerism analysis in patients B1, B2, and B3 was done at day 30).

Chemo indicates chemotherapy; HCT, hematopoietic cell transplantation; GvHD, graft-versus-host disease; ALL, acute lymphatic leukemia; Allo, allogeneic HCT; TBI/VC, total body irradiation (12 Gy), etoposide phosphate, cyclophosphamide; S, stable microsatellites; AML, acute myeloid leukemia; BuCy, busulphan, cyclophosphamide; FBM, fludarabine, carmustine, melphalan (reduced intensity conditioning); NHL, non-Hodgkin lymphoma; Flu/TT, fludarabine, thiotepa (reduced intensity conditioning); NE, not evaluable; ND, not done; NA, not applicable; MDS, myelodysplastic syndrome; CML, chronic myeloid leukemia; MSI, microsatellite instability; MPS, myeloproliferative syndrome; Auto, autologous HCT; CarTh, carmustine, thiotepa; MM, multiple myeloma; HDMEL, high-dose melphalan; BEAM, carmustine, cytosine arabinoside, etoposide phosphate, melphalan; HD, Hodgkin disease; Ca, cancer; VIC, etoposide phosphate, carboplatin, ifosfamide.

History of multiple (≥ 3) myelosuppressive chemotherapies before HCT

Day after HCT or last chemotherapy

Occurrence of graft-versus-host disease (GvHD) any time after HCT, maximal grade; 0 indicates no GvHD; I-IV, grade acute GvHD; Lim, limited chronic GvHD; Ext, extensive chronic GvHD

At the time of buccal sampling, signs of mucositis or oral GvHD were present

These subjects had a history of oral GvHD. Subjects B16 and B24 developed secondary squamous cancers (see Table 3)