<b><i>Background:</i></b> Keratinocyte carcinomas, particularly squamous cell carcinoma (SCC), occur more frequently and aggressively in solid-organ transplant recipients (SOTRs) than in the general population. Systemic retinoids are effective in secondary prevention of keratinocyte carcinomas in this population, but their use is limited by adverse effects including a rebound effect in cases of treatment discontinuation. <b><i>Objective:</i></b> Our aim was to determine whether low-dose acitretin is efficient in the secondary prevention of keratinocyte carcinomas in SOTRs. <b><i>Methods:</i></b> This retrospective case-crossover study was conducted at a specialized dermatology clinic for SOTRs in a large transplantation center in 2010–2017. Patients with at least 1 previous keratinocyte carcinoma who were treated with acitretin 10 mg/day for 2 years were included. The main outcome was the difference in the number of new keratinocyte carcinomas diagnosed during treatment compared to during the 2-year pretreatment period. <b><i>Results:</i></b> The cohort included 34 SOTRs. A significant reduction in the mean number of new keratinocyte carcinomas during treatment relative to the pretreatment period was observed (1.7 vs. 3.6, –53% <i>p</i> = 0.002). Similar results were noted on analysis by tumor type, for both SCC and basal cell carcinoma. <b><i>Conclusion:</i></b> This study of SOTRs demonstrated positive results for low-dose acitretin as a chemoprevention of keratinocyte carcinomas in this population.
Cellular immunity predominates over humoral immunity after homologous and heterologous mRNA and vector‐based COVID‐19 vaccine regimens in solid organ transplant recipients