Salivary Changes before and after Hematopoietic Stem Cell Transplantation: A Systematic Review

Abstract

A B S T R A C T Severe oral problems, including oral mucositis (OM) and xerostomia, often occur after conditioning therapy for hematopoietic stem cell transplantation (HSCT). Saliva plays a major role in protecting the oral mucosa and teeth. Alterations in salivary flow rate or salivary components resulting in decreased salivary defence mechanisms may affect oral/mucosal health and may influence the severity of OM. A systematic review was conducted to assess the current scientific knowledge on changes in salivary function and composition before and after HSCT. All English or Dutch articles examining salivary flow rate or salivary components before and after HSCT were included after title/abstract selection by 2 independent reviewers (weighted k = .91). After quality assessment and exclusion of all research groups with both children age <14 years and adults, 33 articles were included for data analysis. Overall, the salivary flow rate was decreased at several days and months after HSCT. Although several salivary components were studied, most components were examined in only 1 or 2 studies with different patient populations or at different time points after HSCT. At 7 days after HSCT, albumin and proinflammatory cytokines were increased, whereas secretory IgA and components of the salivary antioxidant system were decreased. Secretory IgA levels were still reduced at 1 month after HSCT but returned to pre-HSCT values at 6 months after HSCT. Lactoferrin, secretory leukocyte protease inhibitor, and b 2 -microglobulin levels were increased at 6 months after HSCT. Our findings show that changes in saliva reflect an inflammatory response occurring immediately after HSCT, followed by evidence of increased salivary antimicrobial defense mechanisms by 6 months after HSCT.

Common oral diseases, hyposalivation and survival post‐HSCT, a longitudinal study

“…This commonly observed hyposalivation and gradual improvement of SSFR over time after HSCT is in line with previous studies and further supports the findings which have shown cytotoxic effects of chemotherapy and irradiation to damage salivary glands. Apocrine functions then regenerate gradually during years . However, in this study the SSFR of HSCT recipients with severe cGVHD did not return back to the initial level within the 24 months.…”

“…Thus, the former studies may exaggerate the regeneration potential of salivary tissues. 16,17,27,28 Nonetheless, in our previous study, hyposalivation and persisting sicca symptoms were observed to be relatively common several years post-HSCT. 8 Hyposalivation was not associated with acute or chronic GvHD or oral manifestation of GvHD.…”

“…[13][14][15][16] Additionally, hyposalivation and xerostomia (subjective sensation of dry mouth) can lead to oral discomfort, may affect the patient's ability to eat and cause increased need of supportive cancer care. 8,13,14,16,17 Hyposalivation is associated with oral GvHD and mucositis and could thus even be associated with survival. 12,[18][19][20][21][22] Among HSCT recipients, this has not been studied, but hyposalivation and associated saliva alterations have been observed to co-exist with aspiration pneumonia as well as frailty and death among elderly.…”

Risk factors and implications of oral mucositis in recipients of allogeneic hematopoietic stem cell transplantation

“…However, current therapeutic approaches provide only limited protection. Our increasing understanding of mucositis pathophysiology, as well as the importance of shifts in salivary function, and the microbiota composition offers exciting new avenues for novel strategies.…”

Salivary antioxidant enzymes associated with oral toxicity in haematopoietic cell transplantation: An observational study

“…Changes in saliva have been extensively described in oncologic patients, including HCT patients 7 . However, few studies have addressed the role of salivary antioxidant enzymes in the process of oral mucositis and xerostomia 8‐11 .…”