Oral mucositis in paediatric cancer patients undergoing allogeneic hematopoietic stem cell transplantation preventively treated with professional dental care and photobiomodulation: Incidence and risk factors.

BACKGROUND: Oral mucositis (OM) is an important side effect related to allogeneic hematopoietic stem cell transplantation (allo-HSCT), and it has been associated with a significative reduction of quality of life. A negative impact of OM in paediatric patients could result in increased use of parenteral feeding and opioids, longer periods of hospitalization, and a higher risk of systemic infection. AIM: To investigate the clinical features and clinical outcomes associated with OM development and severity in hematological cancer paediatric patients undergoing allo-HSCT who underwent professional dental care (PDC) and photobiomodulation (PBM) as prophylactic treatment. DESIGN: Medical data and OM presentation were retrieved retrospectively from all patients younger than 18 years who received allo-HSCT between 2013 and 2016. The incidence of OM was assessed and graded by two oral medicine specialists following the WHO guidelines, and it was correlated with clinical parameters. RESULTS: Forty-nine consecutive paediatric patients were included. OM was diagnosed in 73.5% of patients, and in 36.1% of patients, OM was classified as severe. Acute lymphoblastic leukemia as a primary diagnosis and the use of a myeloablative regimen were associated with OM development. The primary diagnosis and use of total body irradiation (TBI) were associated with aggressive OM. Neither the incidence nor the severity of OM affected the overall survival, whereas only the use of a myeloablative regimen and a high body mass index (BMI) were determinants of lower OM-free survival rates. CONCLUSIONS: A myeloablative conditioning and a high BMI were observed to be independent prognostic determinants of a lower OMFS rate. The cluster analysis allowed us to outline patient profiles with greater susceptibility to the development and severity of oral mucositis, which seems to be a useful tool to determine the risk of OM in paediatric patients.

Herpesviruses in the oral cavity of patients subjected to allogeneic hematopoietic stem cell transplantation and its relationship with oral mucositis.

OBJECTIVES: This study was performed to characterise oral shedding of herpesviruses in patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT) and to investigate its relationship with oral mucositis (OM). MATERIALS AND METHODS: PCR and enzymatic digestion were conducted to identify oral shedding of herpesviruses and its correlation with OM development in 31 patients. The samples were collected at three sites in the oral cavity and at 5 times during follow-up; two additional collections were made from patients who developed ulcerative OM. RESULTS: HSV-1, EBV, CMV, HHV-6A, HHV-6B, and HHV-7 were detected in 4.97%, 16.02%, 4.41%, 2.20%, 3.31%, and 68% of the oral mucosal samples, respectively; 4.41%, 16.57%, 5.52%, 2.20%, 5.52%, and 63.53% of supragingival samples, respectively, and 4.41%, 18.23%, 2.76%, 1.65%, 2.75%, and 35.91% of subgingival samples, respectively. OM was diagnosed in 13 patients. The presence of HHV-7 in C1 (oral mucosa: p = 0.032) and C2 (supragingival: p = 0.009; subgingival: p = 0.002) was significantly increased in patients who developed OM, and patients exhibiting HHV-7 shedding in the oral cavity were 3.32-fold more likely to develop OM. CONCLUSIONS: Patients who developed OM showed higher HHV-7 shedding in the oral cavity at nadir (immediately prior to OM development), suggesting modifications to the inflammatory microenvironment. CLINICAL RELEVANCE: HHV-7 may be involved in oral dysbiosis in HSCT-related OM; enhanced understanding of its role in the pathogenesis of OM may lead to the development of strategies for managing and preventing this common side effect of alloHSCT.