Serodiagnosis of cutaneous leishmaniasis in Jordan using indirect fluorescent antibody test and the enzyme-linked immunosorbent assay

The usefulness of IFAT and ELISA, in the detection of antibodies to cutaneous leishmaniasis (CL) in Jordanian cases was studied. Serum samples were collected from three groups of confirmed or putative CL patients (n=100), 132 healthy blood donors, 10 patients with pulmonary tuberculosis (TB), and 16 patients with typhoid fever (TF). Antigens for both tests were prepared from promastigotes of a Leishmania major isolate. At a serum dilution of respectively 1:16 and 1:100 both IFAT and ELISA had a sensitivity of 81%, whereas in the healthy control group their specificities were 95 and 96%. Maximal titers in the 37 parasitologically-proven cases were 1:128 in IFAT and 1:800 in ELISA. Antibodies were detected in about 50% of the 42 cases that had negative parasitological tests but had typical lesions with IFAT-titers up to 1:64 and ELISA titers up to 1:400. However, antibodies were detected in 19% of the 21 clinically-suspected cases of CL with maximal titers of 1:32 in IFAT and 1:200 in ELISA. A variation in antibody level was detected in the treated and the non-treated patients who were followed up for few months after diagnosis. One serum specimen taken from a patient with TB and two sera taken from patients with TF cross-reacted with Leishmania antigens in both IFAT and ELISA. This false positivity could be eliminated by absorption of these sera with their homologous antigens. There was no significant relationship between antibody level and duration of infection with CL. On the other hand, a significant relationship between antibody level and number of CL lesions was found. Although both tests would be useful for detection of circulating antibodies in cases suspected of having CL, especially in those having several lesions, IFAT is recommended for use in Jordan for its simplicity and rapidity