OBJETIVO: O ensaio de enzyme-linked immunosorbent assay (ELISA) para a pesquisa de anticorpos anticardiolipina (aCL) é o mais importante teste para o diagnóstico da síndrome antifosfolipídica (SAF). Entretanto esse teste também pode ser positivo em algumas doenças infecciosas. Tem sido sugerido que a detecção de anticorpos para uma mistura de fosfolípides ou para beta2-glicoproteína I (beta2-GP I) teria uma maior especificidade para a SAF que o teste de ELISA-padrão para aCL. O objetivo do presente estudo é comparar a especificidade de três testes para anticorpos antifosfolípides (aFL) em pacientes com doenças infecciosas. MÉTODOS: Anticorpos antifosfolípides foram pesquisados por três técnicas de ELISA, ou seja, o teste-padrão para aCL, o kit de ELISA APhL® e o teste para anti-beta2-GP I em pacientes com doenças infecciosas, tais como sífilis (69), leptospirose (33) e Calazar (30). RESULTADOS: A freqüência de positividade de aFL da classe IgG em pacientes com sífilis, leptospirose e Calazar foi de 13/69 (19%), 9/33 (27%) e 2/30 (6%), respectivamente, com o ELISA-padrão para aCL versus 1/69 (1,4%), 0/33 (0%) e 0/30 (0%) com o kit de ELISA APhL®. A positividade do isotipo IgM foi de 10/69 (14%), 4/33 (12%) e 1/30 (3%), respectivamente, com o ELISA-padrão para aCL, e 1/69 (1,4%), 0/33 (0%) e 0/30 (0%) com o kit de ELISA APhL®. Anticorpos da classe IgG contra beta2GPI foram detectados em 14/69 casos de sífilis (20%), 6/33 casos de leptospirose (18%) e 16/30 casos de Calazar (53%). Assim, o kit de ELISA APhL® apresentou uma maior especificidade: 97% (95% CI: 92%-99%) comparado com 81% (95% CI: 74%-87%) para o teste de aCL-padrão e 72% (95% CI: 64%-79%) para o teste de anticorpos anti-beta2 GPI. CONCLUSÕES: O kit de ELISA APhL® parece ser mais específico para a SAF que o ELISA-padrão para aCL, assim como o teste para anti-beta2GPI. Esse kit pode ser usado para ajudar no diagnóstico e na confirmação da SAF.

OBJECTIVE: The standard enzyme-linked immunosorbent assay (ELISA) for anticardiolipin (aCL) antibodies is the most important test for the diagnosis of antiphospholipid syndrome (APS). However, the test is also positive in some infectious diseases and other non-related syndromes. It has been suggested that the detection of antibodies to a mixture of phospholipids or to beta2-glycoprotein I (beta2-GP I) has higher specificity for APS than the standard aCL ELISA. The aim of the present work is to compare the diagnostic specificity of three different antiphospholipid (aPL) assays in patients with infectious diseases. METHODS: Antiphospholipid antibodies were searched by three ELISA techniques, namely standard aCL, APhL® ELISA kit and anti-beta2-GP I, in sera of patients with infectious diseases, including syphilis (69), leptospirosis (33) and visceral leishmaniasis (30). RESULTS: The frequency of positivity of IgG aPL in patients with syphilis, leptospirosis and Kala-azar was 13/69 (19%), 9/33 (27%) and 2/30 (6%), respectively, using standard ELISA, versus only 1/69 (1.4%), 0/33 (0%) and 0/30 (0%) positivity by the APhL® ELISA kit. The positivity of the isotype IgM aPL was 10/69 (14%), 4/33 (12%) and 1/30 (3%), respectively, by the standard ELISA, and 1/69 (1.4%), 0/33 (0%) and 0/30 (0%) by the APhL® ELISA kit. The presence of significant levels of IgG anti-beta2GPI was observed in 14/69 cases of syphilis (20%), 6/33 cases of leptospirosis (18%) and 16/30 cases of Kala-azar (53%). The APhL® ELISA kit had superior performance showing the highest specificity: 97% (95% CI: 92%-99%) for IgG compared to 81% (95% CI: 74%-87%) for standard ELISA and 72% (95% CI: 64%-79%) for anti-beta2 GPI assay. CONCLUSIONS: The APhL® ELISA kit proved to be significantly more specific than the aCL standard ELISA and the anti-beta2GPI ELISA, and it should be used to help in the diagnosis and confirmation of APS.

In this study, the ability of maxadilan and Lutzomyia longipalpis salivary gland lysate to enhance the infection of CBA mice by Leishmania major and of BALB/c mice by L. braziliensis was tested. No difference was observed between sizes of lesion in CBA mice infected with L. major and treated or not with salivary gland lysate or maxadilan, although they were injected in concentrations that induced cutaneous vasodilation. Although parasites were more frequently observed in foot pads and spleens of animals treated with maxadilan than in the animals treated with salivary gland lysate or saline, the differences were small and not statistically significant. The lesions in BALB/c mice infected with L. braziliensis and treated with maxadilan were slightly larger than in animals that received Leishmania alone. Such differences disappeared 14 weeks after infection, and were statistically significant only in one of two experiments.

Positive Montenegro's skin test is a delayed type hypersensitivity reaction widely used as indicative of previous infection with Leishmania in both humans and dogs. Montenegro's antigen consists of a crude Leishmania antigen solution, usually containing thimerosal as preserving agent. In this work it is shown that a large proportion of dogs (11 out of 56) examined in an endemic area of leishmaniasis presented induration at the site of injection of a diluent containing thimerosal alone. This clearly demonstrates that thimerosal leads to a high number of false positive skin reactions in dogs and that its use in Montenegro's skin test antigenic preparations should be avoided.