Immunopathology of parasitic diseases: a conceptual approach.

These studies would indicate tremendous variations in the clinical manifestations of parasitic disease, resulting from characteristics of the parasite, the host, and their interaction. They further suggest that the conceptual mechanistic model described in the introduction is highly applicable. Previous evidence to substantiate the validity of such a model in schistosomiasis, a variety of protozoan diseases, and leprosy has already been presented (Phillips and Fox, 1982). This report would appear to lend additional credence to the postulates and suggests that upon scrutiny, the model represents a reasonable explanation for a wide variety of clinical manifestations of a parasitic disease. In addition, it may provide a working hypothesis for the interpretation of the immunopathology found in other diseases such as filariasis. Figure 3 compares and contrasts schistosomiasis and filariasis within the context of this hypothesis. Immunopathology results from the relative balance of host-parasite immunogenic factors and modulatory specific and nonspecific factors. The resultant immunopathology results from a number of immunologic mechanisms, but for the sake of comparison can be placed in certain analogous groups. Clearly, although a number of experimental questions still exist, vis-à-vis these analogies, it would appear that they are reasonable comparisons. It is hoped that such a conceptual approach might provide a useful framework for an understanding of the spectrum of immunopathology resulting from parasitic disease. These concepts might possibly lead to the eventual control of immunopathology.