Following solid organ transplantation (SOT), patients often face increased risks of viral reactivation due to immunosuppressive drugs. While cytomegalovirus (CMV) is a well-recognized concern, Herpes Simplex Virus-1 (HSV-1) also poses a threat. A recent study published in Transplant Infectious Disease sheds light on the prevalence and characteristics of subclinical HSV-1 reactivation in SOT recipients.
The research team, led by Molly Fischer and Drs. Steve Pergam, Margaret Green, and Christine Johnston from Fred Hutchinson Cancer Center, enrolled 15 SOT recipients who were seropositive for HSV-1. Participants self-collected oral swabs three times daily for six weeks to detect HSV DNA, indicative of shedding episodes. The study aimed to determine the frequency and kinetics of these events, particularly those occurring without clinical symptoms.
High Prevalence of Asymptomatic Shedding
Of the 15 participants, 12 (80%) experienced at least one HSV-1 shedding episode during the study. Notably, 27 out of the 32 total shedding episodes were subclinical, meaning they occurred without any visible oral lesions. This finding underscores the potential for underestimation of HSV-1 reactivation in SOT recipients when relying solely on clinical symptoms for detection.
Viral Load and Shedding Duration
The researchers also assessed viral DNA levels in the oral swabs. They observed that longer shedding episodes (lasting more than 24 hours) had the highest median viral titer. This suggests a possible correlation between the duration of viral shedding and the extent of viral replication, potentially impacting patient outcomes.
Implications for Patient Management
"Our pre-formed hypotheses were that transplant (immunosuppressed) patients would shed HSV frequently, and for longer periods than those with normal immune systems – so to see that our data supported our hypotheses was important," said Ms. Fischer. The frequency of brief episodes of reactivation was also surprising. These findings highlight the need for increased awareness and monitoring of HSV-1 reactivation in SOT recipients, even in the absence of clinical symptoms. Further research is warranted to determine the clinical significance of subclinical shedding and to develop strategies for preventing or managing these events to improve patient outcomes after transplantation.
