Clarithromycin and azithromycin induce apoptosis of activated lymphocytes via down-regulation of Bcl-xL.

To evaluate the anti-inflammatory action of macrolide antibiotics, we examined whether macrolide antibiotics could induce apoptosis of activated lymphocytes. The proportion of apoptotic cells was augmented by clarithromycin (CLR) and azithromycin (AZM) compared with control. There was no significant difference in Fas and Fas-ligand expression between the control and macrolide-treated groups. CLR and AZM inhibited the expression of Bcl-xL compared with that of control. Our results suggest that CLR and AZM enhance apoptosis of activated lymphocytes by down-regulation of Bcl-xL.