Quantitation of immunoglobulins in patients with systemic leishmaniasis show a rise in IgM and IgG. Complement C3 levels in severely ill patients were very low, whereas generally within normal range in patients with uncomplicated recoveries. The cell mediated immune response of those kala-azar patients examined appeared to be depressed as measured by PHA skin tests. This depression was rapidly reversed following chemotherapy with Glucantim.