Quantification of Plasmacytoid Dendritic Cells and Type 1 Myeloid Dendritic Cells in Peripheral Blood of Renal Transplant Recipients With and Without Squamous Cell Carcinoma

Abstract

Organ transplant recipients are at high risk of developing squamous cell carcinoma (SCC) (1–3). These viralassociated skin cancers cause severe morbidity and may also be life-threatening (4, 5). Thus, regular follow-up by a dermatologist is recommended. The time intervals of the examinations should be determined by the individual’s risk for SCC development (6–8). One of the main risk factors is long-term immunosuppression (3, 9), leading to severe deficits in immunosurveillance. Dendritic cells (DC) play an important role in immuno surveillance, even though they constitute only 0.5% of the leukocytes in blood (10). Plasmacytoid DC (pDC) are a subset of DC. They produce interferon-alpha (IFN-α) and are considered to play a critical role in antiviral immunity (11). Type 1 myeloid DC (mDC1), another DC subset, are responsible for induction of Tcell responses (12). On the basis of the potential of DC to prevent cancer development, we wanted to determine whether renal transplant recipients (RTR) who develop SCC have a reduced quantity of these two DC subgroups in blood compared with RTR who do not develop SCC.