Immune phenotype of peripheral blood cells and skin squamous cell carcinoma in organ transplant recipients.

Evaluation of: Carroll RP, Segundo DS, Hollowood K et al. Immune phenotype predicts risk for posttransplantation squamous cell carcinoma. J. Am. Soc. Nephrol. 21, 713-722 (2010). Squamous cell carcinoma (SCC) of the skin is a common tumor in Caucasians, occurring on sun-damaged skin. The carcinogenesis of SCC is multifactorial and the most important risk factor is UV radiation. Interestingly, SCC is the most frequent malignancy following organ transplantation, with a 60-100-fold increased risk compared with the general population. Carroll et al. recently identified more than 35 FOXP3+ cells per microl and less than 100 natural killer cells per microl in peripheral blood and previous SCC as risk factors for SCC in renal transplant recipients. The ratio of CD8/FOXP3 cells was significantly lower in the microenvironment of SCC from kidney transplant recipients compared with immunocompetent patients. These findings provide hitherto unknown details about the potential influence of immunomodulation by drugs on the development of SCC in kidney transplant recipients. While this study population may not relate to all kidney transplant recipients, particularly those on other immunosuppressive regimens, Carroll et al. provide us with a tool to aid recognition of patients at a higher risk for SCC. Further studies will help to translate these findings into potentially useful tools for the dermatological management of kidney transplant recipients.