Table 1. Characteristics of the cohorts studied.

	Healthy	HIV-1	HIV-2
Number (male/female)	18 (7/11)	22 (17/5)	28 (9/19)
Age, years	42±2	39±2#	48±3
	[25]–[57]	[23]–[61]	[19]–[78]
Ethnicity: Caucasian/Black	16/2	16/6	14/14
CD4 T cell count, cells/µl	935±63a	569±105**	666±80*
	[518–1397]	[18–1848]	[52–1511]
% CD4 T cells	44.9±2.0a	22.8±3.3***	28.5±2.6***
	[34.4–61.1]	[1.3–47.2]	[7.1–54.1]
% HLA-DR+ within CD4	4.1±0.4b	17.8±3.1c; ***	11.3±1.7**
	[1.9–7.6]	[1.7–54.5]	[1.9–36.3]
% HLA-DR+CD38+ within CD8	4.4±1.4b	29.7±4.2c; ***	20.6±3.6***
	[1.3–22.7]	[1.4–62.2]	[0.6–69.5]
Viremia, HIV RNA copies/ml	NA	672,310±294,026d; ##	3,035±1,125d
		[40–4,470,000]	[200–26,263]
Proviral DNA, copies/106 PBMC	NA	172±55e	173±60e
		[5–975]	[5–1033]

Data are mean±SEM with limits in brackets. NA, not applicable. ^#p<0.05 in comparison with HIV-2 infected patients; ^*p<0.05, ^**p<0.01, ^***p<0.001 in comparison with healthy individuals. ^an = 17; ^bn = 16; ^cn = 21; ^d4 out of 22 HIV-1 patients and 20 out of 28 HIV-2 patients had undetectable viremia. In these cases, the cut-off value of the test (40 and 200 RNA copies/ml for HIV-1 and HIV-2, respectively) was used to calculate the mean; ^eProviral DNA was quantified in 21 HIV-1 and 28 HIV-2 infected patients. It was detectable in all the patients evaluated but in 3 cases from the HIV-2 cohort it was below the cut-off value of the test (5 HIV DNA copies/10⁶ PBMC copies). In these cases, the cut-off value of the test was used to calculate the mean.