Serodiagnosis of Anthroponotic Cutaneous Leishmaniasis (ACL) Caused byLeishmania tropicain Sanliurfa Province, Turkey, Where ACL Is Highly Endemic

Abstract

In this study, we aimed to evaluate the validity of the conventional enzyme-linked immunosorbent assay (ELISA) and the Western blotting test for the diagnosis of anthroponotic cutaneous leishmaniasis (ACL) using serum samples obtained from 51 patients with parasitologically proven nontreated CL (NonT-CL patients) and 62 patients under treatment for CL (UT-CL patients). Additionally, 29 serum samples obtained from patients with parasitologically and serologically proven visceral leishmaniasis (VL) were also used as positive controls, and serum samples from 43 blood donors were used as negative controls. All sera were diluted to the same dilution (1/100). Leishmania infantum MON-1 was used as the antigen in the conventional ELISA. The sera of 27 (93.1%) of 29 VL patients were seropositive by ELISA, while the sera of 40 (78.4%) of 51 NonT-CL patients and 43 (69.3%) of 62 UT-CL patients were seropositive by the conventional ELISA. The absorbance values of the CL patients' sera were significantly lower than the absorbance values of the VL patients' sera. Bands between 15 and 118 kDa were detected in two groups of CL patients. Among all bands, the 63-kDa band was found to be more sensitive (88.5%). When we evaluated the Western blotting results for the presence of at least one of the diagnostic antigenic bands, the sensitivity was calculated to be 99.1%. By using serological tests, a measurable antibody response was detected in most of the CL patients in Sanliurfa, Turkey. It is also noted that this response can be changed according to the sizes, types, and numbers of lesions that the patient has. The Western blot test was found to be more sensitive and valid than the conventional ELISA for the serodiagnosis of ACL. In some instances, when it is very difficult to demonstrate the presence of parasites in the smears, immunodiagnosis can be a valuable alternative for the diagnosis of ACL.

Leishmania tropica in Rock Hyraxes (Procavia capensis) in a Focus of Human Cutaneous Leishmaniasis

“…Reactions with 15 bands ranging from 17-92 kDa were observed. Of these bands, 8 (17,20,21,23,25,30,37, and 53 kDa) were also observed with sera from EI hyraxes and PCR-positive humans, suggesting that the appearance of antibodies against these antigens is indicative of exposure to L. tropica in both species. Reaction to each band was assessed according to its mean net intensity value using the Kodak 1D computerized program as previously described.…”

“…Although serological studies of antibody responses have not been reported previously with hyraxes, it has been used for the diagnosis and study of L. tropica CL. 29,37 Several of the antigens, 17, 20, 21, 23, 25, 30, 37, and 53 kDa, recognized both by infected hyrax and human serum show molecular weights similar to those used in the serodiagnosis of L. tropica CL (27 and 30 kDa), or for monitoring treatment (19 kDa). 37 Thus, hyrax antibody reactivity to specific L. tropica antigens resembles the response mounted by infected humans.…”

“…29,37 Several of the antigens, 17, 20, 21, 23, 25, 30, 37, and 53 kDa, recognized both by infected hyrax and human serum show molecular weights similar to those used in the serodiagnosis of L. tropica CL (27 and 30 kDa), or for monitoring treatment (19 kDa). 37 Thus, hyrax antibody reactivity to specific L. tropica antigens resembles the response mounted by infected humans. Variability in the western blot technique could account for slight protein migration differences.…”

“…Western blot with human sera was found to be more sensitive and valid than the conventional enzyme-linked immunosorbent assay for the serodiagnosis of CL, and it was shown to be useful as an alternative diagnostic tool in instances when it was difficult to demonstrate the presence of parasites in stained tissue smears. 37 Serology is considered an indicator of exposure rather than infection. The discrepancy between the rates of infection shown by PCR and exposure demonstrated by serology in this study could be explained by past infection with persisting antibody levels, possible presence of infection without detectable parasite DNA in blood, or cross-reactivity with trypanosomes or other closely related organisms.…”

Leishmaniasis: diagnostic issues in Europe

“…However, their use is not routine in the Old World due to variable or low sensitivity in endemic countries [106,107]. The sensitivity of ELISA in the Old World reached 60% with L. major, though a recent study from Turkey demonstrated a sensitivity of 88% with L. tropica [108,109]. In the New World, IFAT showed a sensitivity of 27.7% for CL and 56.7% for MCL with L. braziliensis [110].…”