Immunological features of kala-azar.

Serum immunoglobulins, complement C3c, percentage of T and B cells, and skin reactivity to Leishmania were studied in ten cases of kala-azar. Immunoglobulin G was increased in a majority of these patients. The C3c level in two out of six patients tested was lower than normal. The percentage of T cells in peripheral blood of nine patients tested was reduced and in seven of these patients the percentage of B cells was elevated. After a full course of anti-kala-azar therapy the percentage of T and B cells remained the same in five patients studied. All the patients showed a negative skin reaction when they were tested with Leishmania antigen.