CD4 and tuberculosis: We identified a significantly lower frequency of CD4+ T cells in the thoracic LN of SIV+ viral non-controllers when compared with the SIV+ viral controllers and TB-only (SIV-naive) animals (Fig. 2), a difference that could not be observed when assessing the SIV+ group as a whole, and in a tissue that was not examined in Larson et al. (15).