In vitro cellular immunity in Chagas' disease.

In vitro delayed hypersensitivity was studied in patients with either the chronic or the indeterminate phase of Chagas' disease. Normal healthy individuals were used as controls. The leucocyte migration inhibition test was applied using an antigen an extract of culture forms of T. cruzi or an extract of normal rat heart. The results showed that patients with the chronic phase of the disease reacted significantly with both antigens, whereas most patients with the indeterminate phase did not react with heart antigen and only five out of fourteen (35%) reacted with T. cruzi antigen. It is suggested that these individuals may represent patients about to develop the chronic phase of the disease. The relevance of these findings to the immune mechanism influencing the onset of the chronic phase of Chagas' disease is discussed.