3TC levels in tissues of SIV-infected macaques receiving a short-term HAART just after the viremia peak. 3TC and 3TC-TP were measured in the tissues of macaque receiving the AZT/3TC/IDV combination between 14 and 28 days pi (HAART d14-d28). 3TC concentration was high in the colon, 100 times lower in the spleen and 300 times inferior in peripheral LN (a). 3TC-TP showed the same trend in distribution (b). Correlation between 3TC concentration and residual viral DNA (c) and RNA (d) in the lymphoid tissues showed an inverse relationship between 3TC concentration and the residual viral load (c). *: indicated a significant difference (p < 0.05) using a Mann-Whitney test. G mean: Geometric mean, Per LN: peripheral lymph node.