[Immunodiagnostic findings in patients with kala-azar]

Using three immunoreactions (complement-fixation reaction; enzyme immune test; indirect immunofluorescence), antibody formation was tested in 66 patients with kala-azar and 74 controls (blood donors; accident patients). Moderately elevated and high antibody levels for each of three reactions were defined to provide diagnostic criteria. Moderately high or high antibody concentrations against Leishmania antigen were found in one of the three immunoreactions in 9 patients, in two of the three in 21, and in all three in 36 (55%). No Leishmania antigen was found in the serum of the controls. Similar results were obtained for 80% of those serum samples which had been sent in over a period of seven months to check for Leishmania antibodies (455 of 566 samples). In 25 of the remaining 111 serum samples moderate or high antigen concentrations were demonstrated, but in 21 of them in only one test. Leishmania antibodies were found to persist for several months after the clinical symptoms had disappeared. In 22 kala-azar patients the IgG concentrations were clearly elevated (greater than 3000 mg/dl), in five the IgM concentrations were elevated (greater than 400 mg/dl), while the IgA concentrations were normal or slightly decreased. The data indicate that kala-azar cases can be diagnosed with three appropriate immunoreactions which measure antibody concentrations.