Immunosuppression affects CD4+ mRNA expression and induces Th2 dominance in the inflammatory microenvironment of cutaneous squamous cell carcinoma in organ transplant recipients

Squamous cell carcinoma (SCC) is the most frequent cancer in organ transplant recipients (OTRs):. Compared to the general population, OTRs are at a 60up to 100-fold risk. The immune system plays a major role in the fight against SCC, however little is known about the local inflammatory response in SCC at all. We analyzed quantity and quality of the perineoplastic inflammatory SCC microenvironment in immunocompetent patients and immmunosuppressed OTRs. SCC RNA was analyzed in 8 groups relating to Th1 vs. Th2 response: GATA3, IL-12, TH1TH2, ST IL13, ST IL-4, IFN-γ up/ down; IL-4 using Gene Set Enrichment Analysis (GSEA). SCC from 15 immunocompetent patients and 13 OTRs was analyzed by real-time RT-PCR for CD4, CD8, TBET, GATA-3, FOXP3, RORC, IFN-gamma, IL-4, TGF-beta, IL-10 and IL-17A mRNA expression characterizing Th1, Th2, T-reg and Th17 populations. Immunohistochemistry was performed in SCC for FOXP3 expression. RNA expression profile of SCC patients was analyzed for 8 different set of genes relating to Th1 vs. Th2 response: GATA3, IL-12, TH1TH2, ST IL13, ST IL-4, IFN-γ up/ down; IL-4 using Gene Set Enrichment Analysis (GSEA). SCC from 15 immunocompetent patients and 13 OTRs was analyzed by real-time RTPCR for CD4, CD8, TBET, GATA-3, FOXP3, RORC, IFN-gamma, IL-4, TGF-beta, IL-10 and IL-17A mRNA expression characterizing Th1, Th2, Treg and Th17 populations. Immunohistochemistry was performed in SCC for CD3, CD4, CD8 and FOXP3 expression. Considerable inflammation was seen in both patient groups. SCC in immunocompetent patients and OTRs was associated with a mixed Th1 and Th2 gene expression signature. CD4+ mRNA was diminished in immunosuppression, while CD8+ did not vary. Skin adjacent to SCC in OTRs showed Th2 expression pattern as compared to immunocompetent patients. T-BET as well as INF-gamma mRNA expression was decreased in the OTR group. On the other hand GATA-3 and IL-4 mRNA expression did not differ. Although Th17 weighted inflammation, characterized by expression of RORC mRNA was unchanged, IL-17A mRNA level was markedly decreased with immunosuppression. Regulatory T cells, characterized by FOX-P3 and TGF-beta mRNA level, were decreased in OTRs. IL-10 mRNA expression did not vary between the groups. The inflammatory microenvironment of cutaneous squamous cell carcinoma in organ transplant recipients is characterized by an attenuated state of local immune response comprising a lesser quantity of helper T cell response and a Th2 polarized quality. Our findings support the hypothesis that non -tumor-bearing 2 skin adjacent to SCC in OTRs is not necessarily normal and that the local microenvironment may contribute to a field effect contributing to higher recurrence rates and more aggressive behavior observed in these patients.