Background:    Oral graft-versus-host disease (GVHD) is a significant complication after allogeneic stem cell transplantation (SCT) and there is no consistent information about its characteristics in patients after reduced-intensity conditioning regimen FLU/MEL (fludarabine 120 mg/m2 and melphalan 140mg/m2).
    Material/Methods:    This was a single-centre prospective observational study of patients after allogeneic SCT with FLU/MEL conditioning performed during the period 1/2005-12/2007. Characteristics of oral GVHD were observed in 71 patients. The observation was discontinued due to death, donor lymphocyte infusion (DLI) or new chemotherapy administration.
    Results:    In 10/2010, the median duration of the observation of the cohort of the patients was 13 (0.2–69) months, and 42 (35–69) months in the still-ongoing 20/71 (28%) patients. Oral acute GVHD had sporadic 7% incidence, whereas oral chronic GVHD was observed in 33% of patients and persisted with median duration of 188 (11–665) days. Clinical and histopathological features were similar in both acute and chronic oral GVHD and included mucosal lichenoid changes, erythema, ulcerations and pseudomembranes, satellite necrosis, apoptotic bodies and lichenoid interface inflammation.
    Conclusions:    It is necessary to consider complex clinical symptomatology and pathological correlations when classifying the oral GVHD, because local oral symptoms and histopathological features in both acute and chronic oral GVHD forms can be similar. Even though the oral chronic GVHD was mild in the majority of patients, it can be considered as clinically significant due to its incidence, duration and symptomatology. The FLU/MEL conditioning regimen should not be considered as low-risk protocol in this context.

Keywords: Stem Cell Transplantation - adverse effects, Mouth Diseases - pathology, Melphalan - therapeutic use, Graft vs Host Disease - pathology, Chronic Disease, Adult, Acute Disease, Transplantation Conditioning - adverse effects, Transplantation, Homologous, Vidarabine - therapeutic use, young adult