MWCNT could induce alveolar macrophage (AM) apoptosis and apoptotic cells may be engulfed by other AM. TEM analysis of lung sections of rat instilled with 2 mg of MWCNT showed the presence of apoptotic macrophages. This observation is supporting by the quantification of mRNA of (B) Elmo 1, (C) Elmo 2 and (D) Dock 180 suggesting the capacity of macrophages to engulf apoptotic cells. Results are the mean of ± SD obtained on 6 rats. * Significantly different (p < 0.05) from control group.