Glutathione S-transferases and related proteins from pathogenic human parasites behave as immunomodulatory factors. 
There is a rapidly expanding interest into the glutathione S-transferases (GSTs) and the structurally related molecules.  Many of the latter have been identified as members of conserved protein families sharing structural and some times functional properties being particularly involved in heat-shock response, drug resistance and carcinogenesis.  Also, evidence is emerging that members of the GST super family from some pathogens could exert immunomodulatory functions toward the cell of the immune system, involving separate profiles of cytokine gene transcription and different patterns of cell growth, illustrating therefore the 'one gene-dual function' phenomenon.  The implication of these biological properties for pathogenesis is discussed.