Keratinocyte Carcinomas in Immunocompromised Patients Are Reduced After Administration of the Nonavalent Human Papillomavirus Vaccine

Immunosuppression, as seen in solid organ transplant recipients, is highly associated with the development of keratinocyte carcinomas (KCs). Reducing the level of immunosuppression lowers the incidence of KCs but at the cost of increased potential morbidity and mortality. Recent studies have revealed a greater prevalence of HPV DNA, especially that of β-HPV, in KCs of immunocompromised patients compared to KCs of immunocompetent individuals. A prior report demonstrated that the HPV vaccine was associated with reducing KC incidence in immunocompetent patients. The nonavalent HPV vaccine was administered to two immunosuppressed individuals with histories of multiple prior KCs. Both patients are male, with Patient 1 being a liver transplant recipient who was on tacrolimus for an extended period and Patient 2 having Crohn's disease and currently being treated with mercaptopurine. The treatment was well tolerated without adverse events and was associated with dramatic reductions in average incidence of KCs/year in both patients. Patient 1 demonstrated an 88% reduction in new KCs/year (87% squamous cell carcinomas (SCCs); 100% basal cell carcinomas (BCCs) post-injection of the intramuscular vaccine and Patient 2 demonstrated a 63% reduction in incidence of KCs/year (30% SCCs; 100% BCCs). Evidence links the β-HPV genera to the development of SCCs and actinic keratoses. The nonavalent HPV vaccine, containing antigens of the α-HPV genera, may also induce humoral immunity to β-HPV due to shared expression of L1 and L2 capsid proteins. The HPV vaccine may be an effective tool in the prevention of KCs in immunosuppressed patients.