Human papillomavirus E6/7 specific T-cell responses among Asian individuals with cutaneous squamous cell carcinoma

Cutaneous human papillomavirus (HPV)-specific cell-mediated immunity in patients with cutaneous squamous cell carcinoma (SCC) remains poorly understood, particularly in organ transplant recipients (OTRs), who often develop multiple viral warts and SCC under long-term immunosuppression. This study characterized HPV E6/E7-specific T-cell responses in OTRs with SCC and compared them with immunocompetent individuals with SCC. Participants were recruited in Singapore and included OTRs with a history of posttransplant primary SCC (n = 28) and immunocompetent individuals with SCC (n = 10). Fifteen-mer peptides spanning the E6/E7 regions of HPV8, HPV17, HPV49, and HPV98 were synthesized, and HPV-specific T-cell responses were measured using an enzyme-linked immune absorbent spot assay. Most participants showed positive responses to cytomegalovirus peptide, the positive control, with response rates of 82% in OTRs and 70% in immunocompetent participants. Among OTRs, 28.57% responded to HPV17 E6/E7 peptides and 14.29% to HPV98, while responses to HPV8 and HPV49 were lower (7.14% and 3.57%, respectively). In immunocompetent participants, 20% responded to HPV17 and HPV49, 10% to HPV8, and none to HPV98. This study provides preliminary evidence that circulating T cells reactive to selected β-HPV E6/E7 peptide pools can be detected in a subset of Asian participants with cutaneous SCC, including OTRs.