CTSD and amyotrophic lateral sclerosis: Our results also provide the insight that probably the fall of pH is the key regulating factor for promastigote growth inhibition in ALS pre-treated MΦs as because Inhibition of V-ATPase by bafilomycin A1 was found to have a major impact on the phagosome maturation as compared to pepstatin A, an inhibitor of cathepsin D. So, it may be postulated that V-ATPase is more important than cathepsin D in phagosome maturation process of Leishmania loaded ALS pre-treated MΦs.