Background:  We have previously shown in a pediatric Hematopoietic stem cell transplant (HSCT) population that a non-invasive oral rinse can be used to monitor engraftment, neutrophil tissue delivery and susceptibility to infection post-HSCT.

Methods:  Using the same oral rinse protocol, we studied neutrophil tissue delivery kinetics and its relationship to clinical parameters and outcomes following HSCT in 29 adult patients. Oral neutrophil counts were compared to circulating neutrophil levels, oral mucositis scores and patient health status at 6 months post-HSCT.

Results:  Neutrophils were detected on average 8.4 ± 3.4 SD days earlier in the oral tissues than in the blood circulation, enabling us to confirm successful engraftment more than one week earlier than when using blood neutrophil counts alone. As well, in this population the time-span between oral engraftment (OE) and blood engraftment (BE) was a consistent predictor of treatment outcome at 6 months following HSCT where a BE–OE of <6 days resulted in 100% of patients having a negative outcome.

Conclusion:  We conclude that monitoring the timing of neutrophil delivery to the oral tissues with a non-invasive oral rinse has the potential to allow the physician to identify those patients who are at a high risk of HSCT failure within just a few weeks of the initiation of treatment.