CD4 and infection: In paired comparisons, these values were significantly higher than the levels of infection of resting CD4+ T cells from the peripheral blood detected by digital droplet PCR (4282 vs. 263 copies/106 cells, paired t-test: P<0.0001) or by Alu PCR (2977 vs. 600 copies/106 cells, paired t-test: P = 0.0008).