HPV16/18 + Oropharyngeal Carcinomas Are Associated with Enhanced Local Adaptive Immunity
Qian Dai, Tatyana Isayeva, Jie Xu, Margaret Brandwein-Gensler. UAB, Birmingham, AL
Background: HPV promotes many oropharyngeal carcinomas (OPC) and some oral cavity carcinomas (OCC). A meta-analysis found 36% of OPC are HPV+, mostly HPV16. OCC are also associated with HPV, but a lesser degree. Outcomes for OPC HPV+ patients are significantly better than HPV negative patients, the mechanisms for this protective effect are being elucidated. In-vitro evidence show that HPV induces immune tolerance. But clinical data support the idea of HPV-specific immunity. We hypothesize that HPV+ carcinomas are associated with enhanced local adaptive immunity.
Design: We studies consecutive patients resected for OCC (n = 44) and OPC (n = 34). Tumor RNA was extracted from blocks, reverse transcription was performed. Nested quantitative RT-PCR was performed with primers to HPV16 (E6 (including E6*)/E7) and HPV18 (E6/E7). Positive and negative controls (SiHa, HeLa, HPV16+ OPC, and pancreatic carcinoma, water, respectively) were included in all reactions. Tumors were classified as HPV+ only if both concordant E6 and E7 transcripts were present. One tissue section was selected from each case with the strongest cancer-associated lymphocytic response, and double-stained, by immunohistochemistry, for CD4/CD8 (cocktail antibody, ThermoScientific). Whole slide scanning was performed (BioImagene); 10 40X fields were selected from the regions of densest tumor-infiltrating-lymphocytes (TILS), and densest immune response at the tumor-interface. CD8/CD4 cells were quantified as percent cells per 40X field. CD8/CD4 cells were correlated with HPV16/18 status by T-test, comparing mean percentages of CD8/CD4 cells per distribution (TIL, interface), per site (OCC, OPC), per HPV status.
Results: Transcriptionally active HPV16/18 was present in 20/34 (59%) of OPC, and 16/44 (36%) OCC. Cytotoxic CD8 cells were significantly increased in HPV+ OPC, both TILS, and at the interface. Interface CD4 cells were also significantly increased (Table 1). No increase in adaptive immunity was seen in HPV+ OCC (data not shown).
Conclusions: We show that HPV16/18+ OPC are significantly associated with enhanced local adaptive cytotoxic immunity, compared the HPV- OPC. Thus enhanced immunity may constitute another protective mechanismfor HPV-mediated OPC.
|Cell of Interest||Distribution||HPV 16/18 Status||Mean Cell %||Sig (2-tailed)||95% CI Δ Mean Cell %, lower, upper|