Evaluation of a total lymphocyte proliferation assay as a diagnostic tool for cutaneous leishmaniasis

A total blood lymphocyte proliferation (TLP) assay, recently developed for cutaneous leishmaniasis (CL), was evaluated as a tool for diagnosis of CL among patients with active lesions and apparently healthy people in an endemic area of the Jordan Valley. It was found that, in patients with lesions less than 3 months old, the TLP assay appeared insensitive, failing to detect about half of the patients in whom a diagnosis of CL had been made clinically. Blood specimens from patients with lesions of at least 3 months duration showed a positive correlation in 8 out of 10 cases. With healthy people resident in an endemic area the TLP assay was positive for 15 of 20 subjects with a past history of CL, and for only 3 of 16 without such a history. With another group of patients, not residents of an endemic area but who had spent 2 weeks together in an endemic area, and with a group of drug-treated patients, the results of the TLP assay showed a similar pattern: in patients with lesions less than 3 months old the test appeared rather insensitive, but in patients with lesions of more than 3 months duration, there was a high correlation between the TLP and clinical diagnosis.