Abstract
By means of planimetric analysis and determination of 3H-thymidine labelling indices of mononuclear cells infiltrating the dermis, it has been suggested that the cellular arm of the immune system is activated after infestation of the human host's skin by the scabies mite. Subtle modifications of host-parasite relationships may explain why a single pathogenetic agent (i.e. the scabies mite) is able to evoke such a wide range of clinical lesions in the host.