Microchimerism in labial salivary glands of hematopoietic stem cell transplanted patients

Oral Diseases (2011) 17 , 484–488 Objective: Microchimerism has been extensively investigated in autoimmune diseases, which display similarities with graft‐vs‐host disease. This study was conducted to investigate the presence of microchimerism in minor salivary glands of hematopoietic stem cell transplanted patients, one of the targets of graft‐vs‐host disease. Methods: Labial salivary glands biopsy specimens from 11 stem cell transplanted patients were analysed. The samples were grouped in control (five specimens from a female‐to‐female transplantation) and study group (five glands from male‐to‐female transplantation). One male transplanted patient was used as a positive control. Fluorescence in situ hybridization with Y‐chromosome probe and immunofluorescence with anticytokeratin AE1/AE3 and CD45 were used to identify Y‐chromosome positive glandular epithelial cells from allogeneic hematopoietic stem cell transplanted patients. Results: In the study group, all samples were positive to Y‐chromosome and cytokeratin AE1/AE3, in agreement with the pattern exhibited by male labial salivary gland. None of the samples from control group were positive to Y‐chromosome despite being positive to cytokeratin AE1/AE3. Positivity to CD45 was not relevant. Conclusion: Microchimerism in the labial salivary glands of sex‐mismatched stem cell transplanted patients is a real phenomenon. Further studies are necessary to elucidate the impact of this phenomenon on the clinical status of stem cell transplanted patients.