The objective of this study was to test the relationship between histological changes in minor salivary glands (MSG) and chronic GVHD (cGVHD) severity and OS of hematopoietic SCT (HSCT) patients, and to discriminate the participation of events preceding HSCT that damage MSG, from those linked to cGVHD. The MSG of 57 HSCT patients who were divided into two groups-oral cGVHD (36 cases) and non-cGVHD (21 cases)-were compared with the MSG of a control group of 19 non-HSCT individuals. cGVHD changes were assessed according to National Institutes of Health (NIH) consensus and the systems of Horn et al. Acinar areas and mononuclear cell subsets were set through morphometry. Horn's 'periductal lymphocytic infiltrate' correlated with an extensive form of cGVHD and NIH 'periductal lymphocytes with exocytosis into duct' correlated with global survival. Measurements of the acinar area differed between the three groups, being the lowest in cGVHD patients, but also reduced in non-cGVHD patients. Significant differences among CD45, CD45RO, CD4 and CD8 immunomarked cells/mm(2) were found by comparing the two groups of HSCT patients. In brief, periductal lymphocytic infiltrate and exocytosis implies inflammatory activity and, consequently, might reflect the cGVHD status and influence survival. Acini loss in non-cGVHD patients may be due to pre-transplant events, but massive lymphocyte infiltrate is part of the cGVHD process.