CD4 and benign prostatic hyperplasia: There was no difference in frequency of total T cells expressing co-stimulatory receptor CD27, but CD4+/CD27+ were found decreased in frequency in BPH tissue as compared to PBMCs (64.4% vs. 73.0%, p=0.004) while CD8+/CD27+ were increased in BPH tissue (60.7% vs. 46.0%, p=0.023) (Figure 1 and Table 3).