CTLA4 and benign prostatic hyperplasia: T cells expressing co-inhibitory receptors lymphocyte-activation gene-3 (LAG-3), programmed cell death-1 (PD-1), T cell immunoglobulin mucin-3 (TIM-3) or cytotoxic T lymphocyte-associated protein-4 (CTLA-4) were increased in frequency in BPH tissue in all T cell compartments (total CD3+ T cells, CD4+ and CD8+ T cells) as compared to PBMCs.