Immunologic markers of clinical evolution in children recently infected with Leishmania donovani chagasi.

The study attempted to identify immunologic markers for progression of Leishmania donovani chagasi infection to disease in children in an area endemic for visceral leishmaniasis (VL). [3H]thymidine uptake of lymphocytes stimulated with L. donovani chagasi antigen from children with asymptomatic infection (25,286 +/- 11,648) and from children with self-healing subclinical infection (15,511 +/- 4681) was greater (P = .001) than that observed with lymphocytes from children who progressed to classic VL (4811 +/- 2984). The interferon-gamma (IFN-gamma) levels from asymptomatic and subclinically infected children (74 +/- 90 units/ml) were higher (P = .02) than those observed in children who progressed to VL (7 +/- 8 units/ml). Absence of lymphocyte blastogenesis and IFN-gamma production were associated with progression of infection to classic VL. In the presence of these markers, children should be closely followed to identify signs and symptoms that would permit early initiation of therapy.