Intact APM and PD-1:PD-L1 pathway upregulation in HIV-infected head and neck cancer patients.

Abstract

6058 Background: HIV-infected individuals have a higher incidence of oral infection with human papillomavirus (HPV) and possibly a higher incidence of head and neck cancer (HNC). Whether this observation reflects defects in the ability of this Òimmune-compromisedÓ patient population to mount sufficient tumor specific immune responses and/or reflects activation of immune escape mechanisms is not known. To address this question, we investigated the expression of HLA class I antigen processing machinery (APM) components and PD-1:PD-L1 pathway activation in HIV(+) HNC patients. Methods: 62 HIV(+) HNC patients diagnosed between 1991-2011 from five tertiary care referral centers in the United States and matched HIV(-) HNC controls were identified. HLA class I APM component, PD-1, and PD-Ll expression were analyzed by immunohistochemical staining. Clinical data was abstracted from the medical records. Results: 44 of 62 (71%) HIV(+) HNC cases were matched based on gender, age ( < 10 years), and anatomic sub-site to HIV(-) HNC patients. There was no significant difference between the cases and controls in HLA-A, HLA-B/C, LMP2, and TAP1, as well as PD-1 and PD-L1 expression. Overall, 62% of all subjects had high PD-1 expression and 82% of the subjects expressed PD-L1. HLA-A, HLA-B/C, and LMP2 expression was significantly correlated with moderate to high PD-1 expression in the HIV(+) HNC cases (p = 0.004, p = 0.026, and p = 0.006, respectively) but not in the HIV(-) controls. Similarly, HLA-A expression was also significantly associated with PD-L1 expression only in the HIV(+) HNC cases (p = 0.029). Conclusions: No defects were detected in the expression of the HLA class I APM components tested. PD-1:PD-L1 pathway was found to be upregulated in both HIV(+) and HIV(-) HNC patients. Our data suggest that recently approved anti-PD-1 immunotherapy should not exclude HIV(+) patients.