Programmed death-1 expression on CD4R and CD8R T cells in treated and untreated HIV disease Leslie R. Cockerhama, Vivek Jaina, Elizabeth Sinclairb, David V. Gliddenc, Wendy Hartogenesisa, Hiroyu Hatanoa, Peter W. Hunta, Jeffrey N. Martinc, Christopher D. Pilchera, Rafick Sekalyd, Joseph M. McCuneb, Frederick M. Hechta and Steven G. Deeksa Background: There is intense interest in the role of programmed death 1 (PD-1) in causing persistent T-cell dysfunction in HIV infection. However, the impact of HIV infection and antiretroviral treatment (ART) on the expression of PD-1 on T cells is still poorly defined. Methods: PD-1 was measured longitudinally in a cohort of recently HIV-infected individuals (n ¼ 121) who started ART early (