Type 1- and type 2-like lesional skin-derived Mycobacterium leprae-responsive T cell clones are characterized by coexpression of IFN-gamma/TNF-alpha and IL-4/IL-5/IL-13, respectively.

In an earlier study, we generated a large number of Mycobacterium leprae-responsive and M. leprae-nonresponsive T cell clones (TCC) from the lesional skin of immunologic unstable borderline leprosy patients. In that study, we divided TCC into type 1- and type 2-like on the basis of their IFN-gamma and IL-4 expression. To explore whether other cytokines are coproduced along with IFN-gamma and IL-4, we investigated the secretion of a panel of other cytokines (TNF-alpha, IL-5, IL-6, IL-10, and IL-13) by a large number of these TCC. Upon analysis of 139 M. leprae-responsive TCC, we observed a positive correlation in the coproduction of IFN-gamma/TNF-alpha (r = 0.81), and in that of IL-4/IL-5 (r = 0.83), IL-4/IL-13 (r = 0.80), and IL-5/IL-13 (r = 0.82). Polarized type 1-like TCC produced dominantly IFN-gamma/TNF-alpha, and polarized type 2-like TCC predominantly IL-4/IL-5/IL-13. Most type 0-like TCC produced both sets of cytokines. In contrast, type 1- and type 2-like subsets of M. leprae-nonresponsive TCC (n = 58) did not show the same coexpression of these cytokines. Furthermore, when the differential expression of a broad panel of cytokines by individual M. leprae-responsive TCC is considered, it appeared that additional phenotypes could be recognized. These results suggested that distinct isotypes of type 1- and type 2-like T cells, based on the secretion of a panel of cytokines, may reflect M. leprae-specific characteristics.

Associaçäo entre hanseníase e infecçäo pelo vírus da hepatite B: estudo de caso-controle / Association between leprosy and hepatitis B virus infection: a case-control study

Um estudo de caso-controle para investigar a associaçäo entre a hanseníase e infecçäo pelo vírus da hepatite B (VHB) foi conduzido no período de 1992/93, na cidade de Goiânia, GO, e municípios contíguos. Para o estudo de caso-controle, 552 pacientes de hanseníase de 10 a 70 anos foram incluídos. Os controles (N=552) foram selecionados de indivíduos com ausência de sinais e sintomas sugestivos de hanseníase oriundos da demanda espontânea de ambulatórios de 7 unidades de saúde. Foram coletadas amostras de sangue para detecçäo de marcadores ao vírus da hepatite B pela técnica de ELISA. Entre os participantes, 18,1 por cento dos casos e 19,6 por cento dos controles foram soropositivos ao anti-HBc. A associaçäo da hanseníase e anti-HBc entre casos e controles apresentou "odds ratio" de 0,9 (IC 95 por cento 0,7 - 1,3) para a categoria de multibacilar; 1,0 (IC 95 por cento 0,7 - 1,3) para a de paucibacilar e 1,1 (IC 95 por cento 0,8 - 1,5) para a de provável. Os resultados mostraram: (i) prevalências semelhantes dos marcadores de exposiçäo, de imunidade e de estado de portador; (ii) capacidade similar para produçäo de anti-corpos protetores avaliados através dos percentuais do marcador anti-HBs e quantitativamente, através do Indice de ELISA e (iii) baixa probabilidade de persistência da antigenemia mensurada pelo PPI. Em conclusäo, näo houve evidências epidemiológicas de uma associaçäo entre hanseníase e infecçäo pelos vírus da hepatite B

Serodiagnosis of Chagas' disease by enzyme-linked immunosorbent assay using two synthetic peptides as antigens.

An enzyme-linked immunosorbent assay (ELISA) was developed for detecting antibodies against Trypanosoma cruzi. Two synthetic T. cruzi peptides, TcD and PEP2, were used. The specificity and sensitivity of the peptide ELISA were determined with 260 serum samples from individuals living in an area in which Chagas' disease is endemic. ELISAs were performed with the peptides singly or in combination. The evaluation of these tests showed that 168 (93.8%) of 179 serum samples from T. cruzi-infected patients were positive when TcD peptide was used as antigen; 164 (91.6%) samples were positive with PEP2, and 178 (99.4%) samples were positive when the two peptides were combined. Thus, the sensitivity of the ELISA using the two peptides exceeded 99%. The specificity was evaluated by using a panel of 118 serum samples that included samples from 81 individuals living in an area of endemicity with negative serology for Chagas' disease and from 37 patients from areas in which T. cruzi was not endemic but with other pathologies, such as leishmaniasis, tuberculosis, and leprosy. Only two false-positive serum samples were found in this group of individuals, giving a test specificity of more than 98%. Because these peptides can be synthesized and are very stable at room temperature, the use of such reagents can improve the standardization and reproducibility of ELISAs for the serodiagnosis of T. cruzi infection.

Comparative assessment of the leprosy antibody absorption test, Mycobacterium leprae extract enzyme-linked immunosorbent assay, and gelatin particle agglutination test for serodiagnosis of lepromatous leprosy.

A comparative assessment of three serological methods for leprosy diagnosis (the fluorescent leprosy antibody absorption [FLA-ABS] test, the Mycobacterium leprae soluble-extract enzyme-linked immunosorbent assay [ELISA], and the M. leprae particle agglutination [MLPA] test) was carried out. The objective was to identify their performance in clinical and epidemiological diagnosis of leprosy. The study group included 45 lepromatous leprosy patients under treatment. Specificity was > 95% for all three assays, and sensitivity was 95, 58, and 74% for the FLA-ABS test, the MLPA test, and the ELISA, respectively. The only cross-reactivity for M. tuberculosis-infected patients was with the soluble-extract ELISA. Although the FLA-ABS test displayed the highest specificity and sensitivity values, it can only be used in well-developed laboratories, and the patient's clinical and epidemiological background must be considered when results are interpreted because the test remains positive after therapeutic success and could be positive for some household contacts. The MLPA test is easier to perform and interpret, and it is adequate for small laboratories and epidemiological studies intended to detect active untreated or irregularly treated leprosy cases. Therefore, the FLA-ABS and MLPA tests are complementary, and both should be used for serodiagnosis of leprosy.