Presence of anti-Leishmania (Viannia) braziliensis antibodies in blood donors in the West-Central region of the State of Paraná, Brazil.

INTRODUCTION: Serological screening in blood banks does not include all transmittable diseases. American cutaneous leishmaniasis (ACL) has a high detection rate in the municipalities of the State of Paraná. METHODS: This study analyzed the presence of anti- Leishmania braziliensisantibodies in 176 blood donors who live in these endemic areas. The variables were analyzed with the χ2 test and Stata 9.1 software. RESULTS: Twenty (11.4%) samples were positive for the presence of anti- L. braziliensisantibodies. CONCLUSIONS: The high percentage of donors with anti- Leishmania spp. antibodies indicates the need to study the risk of ACL transmission through blood donors.

Evaluation of the reference value for the Montenegro skin test.

INTRODUCTION: The Montenegro skin test (MST) has good clinical applicability and low cost for the diagnosis of American tegumentary leishmaniasis (ATL). However, no studies have validated the reference value (5mm) typically used to discriminate positive and negative results. We investigated MST results and evaluated its performance using different cut-off points. METHODS: The results of laboratory tests for 4,256 patients with suspected ATL were analyzed, and 1,182 individuals were found to fulfill the established criteria. Two groups were formed. The positive cutaneous leishmaniasis (PCL) group included patients with skin lesions and positive direct search for parasites (DS) results. The negative cutaneous leishmaniasis (NCL) group included patients with skin lesions with evolution up to 2 months, negative DS results, and negative indirect immunofluorescence assay results who were residents of urban areas that were reported to be probable sites of infection at domiciles and peridomiciles. RESULTS: The PCL and NCL groups included 769 and 413 individuals, respectively. The mean ± standard deviation MST in the PCL group was 12.62 ± 5.91mm [95% confidence interval (CI): 12.20-13.04], and that in the NCL group was 1.43 ± 2.17mm (95% CI: 1.23-1.63). Receiver-operating characteristic curve analysis indicated 97.4% sensitivity and 93.9% specificity for a cut-off of 5mm and 95.8% sensitivity and 97.1% specificity for a cut-off of 6mm. CONCLUSIONS: Either 5mm or 6mm could be used as the cut-off value for diagnosing ATL, as both values had high sensitivity and specificity.

Evaluation of the reference value for the Montenegro skin test

The Montenegro skin test (MST) has good clinical applicability and low cost for the diagnosis of American tegumentary leishmaniasis (ATL). However, no studies have validated the reference value (5mm) typically used to discriminate positive and negative results. We investigated MST results and evaluated its performance using different cut-off points.

Diagnosis of American cutaneous leishmaniasis by enzyme immunoassay using membrane antigens of Leishmania (Viannia) braziliensis.

This study evaluated the reactivity of membrane antigens of Leishmania (Viannia) braziliensis for the diagnosis of ACL by enzyme immunoassay (EIA). Promastigotes of L. (V.) braziliensis were grown in medium 199 and lysed in a sonicator. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting showed that specific proteins of L. (V.) braziliensis (apparent molecular weights 36 kDa and 48-56 kDa) were recognized by sera from ACL patients. These proteins were eluted from the SDS-PAGE and tested in EIA-IgG with sera from ACL patients, healthy individuals, patients with toxoplasmosis, paracoccidioidomycosis, syphilis, tuberculosis, leprosy, and Chagas disease. The EIA-IgG with membrane antigens allowed us to distinguish patients with ACL from healthy individuals and patients with other diseases (P < 0.0001), and showed a sensitivity of 93.3% and specificity of 90.8%, not including Chagas disease patients. 2D-SDS-PAGE followed by Western blotting was performed to improve the characterization of the antigens, and showed a component with isoelectric points near the acid pH side and apparent molecular weights of 48-56 kDa. The results showed good sensitivity and specificity of EIA-IgG with membrane antigens, indicating their potential use for diagnosis of ACL, as well as seroepidemiological surveys and follow-up of clinically cured patients.

Evaluation of specific primers for species identification of Leishmania (V. ) braziliensis

Leishmanioses são doenças infecciosas com diferentes formas clínicas e prognóstico, portanto a identificação da espécie é importante. Nós avaliamos o desempenho dos iniciadores LBF1/LBR1específicos para L. (V.) braziliensis por PCR e comparamos com resultados de Leishmania spp identificadas por anticorpos monoclonais. Das 29 L. (V.) braziliensis identificadas por anticorposmonoclonais, 16 (53,3por cento) foram detectadas e 7 (63,6por cento) das 11 Leishmania spp não identificadas apresentaram a banda de 536 pb. Estes iniciadores identificaram 87,7por cento de Leishmania do serodema III. Estes iniciadores indicam uma pequena correlação entre os dois métodos usados e também sugerem a existência de uma variabilidade genética entre isolados de L. (V.) braziliensis da regiãonoroeste do estado do Paraná.