The multidrug therapy (MDT) for leprosy treatment adopted by Brazil in the 1990s was important for reducing leprosy in the country; however, recurrent cases remained problematic. Mechanisms involved ...in leprosy recurrence are heterogeneous and can be sorted into three groups: insufficient therapy, bacillary persistence and new infections. This study aimed to analyse the time interval of leprosy recurrence in relation to the therapeutic scheme in the state of Acre. The hypotheses were as follows: 1) treatments (a) rifampicin, ofloxacin and minocycline (ROM) and (b) dapsone (DDS) have a short leprosy recurrence time, 2) treatments based on MDT have a long leprosy recurrence time, 3) there is a dose-response relationship between MDT and the time interval between leprosy episodes.
This retrospective cohort study included 201 patients with a second episode of clinical leprosy at the reference centers for leprosy control in the state of Acre. Exposure was the type of therapeutic scheme as follows: 1) ROM, 2) DDS, 3) MDT
, 4) MDT
, 5) MDT
, and 6) MDT
. Outcome was the time interval between release from treatment and a diagnosis of a recurrent leprosy case. Incidence rate ratios and relative risk Poisson regressions adjusted by age and sex were calculated with 95% confidence intervals.
The 201 patients studied during this retrospective follow-up resulted in a total of 224 cases of recurrent leprosy. Incidence rate ratios within this therapeutic scheme were as follows: 3.3 (2.39, 4.2; ROM/MDT
), 1.12 (0.33, 1.92; DDS/MDT
), 2.17 (1.39, 2.94; MDT
/MDT
), 1.94 (1.13, 2.75; MDT
/MDT
) and 1.26 (0.47, 2.05; MDT
/MDT
). Relative risk Poisson regressions showed a protective effect of MDT
in comparison with ROM (0.22; 0.07, 0.72), MDT
(0.42; 0.21, 0.85), and MDT
(0.44; 0.21, 0.92). No differences among MDT
and DDS (0.71; 0.36, 1.41) and MDT
(0.76; 0.38, 1.49) were observed.
New infection is an important-yet neglected-mechanism in leprosy recurrence in the state of Acre and can challenge the leprosy elimination plan in Brazil. MDT with few doses might be associated with leprosy recurrence due to insufficient therapy or bacillary persistence.
Leprosy, whose etiological agent is Mycobacterium leprae, is a chronic infectious disease that mainly affects the skin and peripheral nervous system. The diagnosis of leprosy is based on clinical ...evaluation, whereas histopathological analysis and bacilloscopy are complementary diagnostic tools. Quantitative PCR (qPCR), a current useful tool for diagnosis of infectious diseases, has been used to detect several pathogens including Mycobacterium leprae. The validation of this technique in a robust set of samples comprising the different clinical forms of leprosy is still necessary. Thus, in this study samples from 126 skin biopsies (collected from patients on all clinical forms and reactional states of leprosy) and 25 slit skin smear of leprosy patients were comparatively analyzed by qPCR (performed with primers for the RLEP region of M. leprae DNA) and routine bacilloscopy performed in histological sections or in slit skin smear. Considering clinical diagnostic as the gold standard, 84.9% of the leprosy patients were qPCR positive in skin biopsies, resulting in 84.92% sensitivity, with 84.92 and 61.22% positive (PPV) and negative (NPV) predictive values, respectively. Concerning bacilloscopy of histological sections (BI/H), the sensitivity was 80.15% and the PPV and NPV were 80.15 and 44.44%, respectively. The concordance between qPCR and BI/H was 87.30%. Regarding the slit skin smear, 84% of the samples tested positive in the qPCR. Additionally, qPCR showed 100% specificity, since all samples from different mycobacteria, from healthy individuals, and from other granulomatous diseases presented negative results. In conclusion, the qPCR technique for detection of M. leprae using RLEP primers proved to be specific and sensitive, and qPCR can be used as a complementary test to diagnose leprosy irrespective of the clinical form of disease.
This study aimed to identify the distribution pattern of leprosy in a hyperendemic municipality in Brazil and determine its relationship with the clinico-epidemiological situation over 11 years. The ...geographic information system, MapInfo, spatial scan statistics and the Moran I index were used to analyze new cases. The digital cartographic base was used to map clusters of new paucibacillary and multibacillary cases and cases in minors under 15 years old. Socioeconomic indicators are shown using the choropleth mapping technique. A reduction in the detection coefficient, increases in high-risk spatial clusters, marked changes in the distribution of high-risk and low-risk clusters, and high-risk clusters of minors under 15 years old were observed from 2006 to 2010, showing recent illness, the presence of active foci, and overlapping of high-risk clusters of multibacillary infection in minors under 15 years old. Leprosy remains a public health problem in Rondonópolis, Mato Grosso State; the high-risk areas require an intensification of control measures and active search strategies to detect new cases.
BACKGROUND Leprosy is a chronic infectious disease caused by Mycobacterium leprae, and compromises the skin and peripheral nerves. This disease has been classified as multibacillary (MB) or ...paucibacillary (PB) depending on the host immune response. Genetic epidemiology studies in leprosy have shown the influence of human genetic components on the disease outcomes. OBJECTIVES We conducted an association study for IL2RA and TGFB1 genes with clinical forms of leprosy based on two case-control samples. These genes encode important molecules for the immunosuppressive activity of Treg cells and present differential expressions according to the clinical forms of leprosy. Furthermore, IL2RA is a positional candidate gene because it is located near the 10p13 chromosome region, presenting a linkage peak for PB leprosy. METHODS A total of 885 leprosy cases were included in the study; 406 cases from Rondonópolis County (start population), a hyperendemic region for leprosy in Brazil, and 479 cases from São Paulo state (replication population), which has lower epidemiological indexes for the disease. We tested 11 polymorphisms in the IL2RA gene and the missense variant rs1800470 in the TGFB1 gene. FINDINGS The AA genotype of rs2386841 in IL2RA was associated with the PB form in the start population. The AA genotype of rs1800470 in TGFB1 was associated with the MB form in the start population, and this association was confirmed for the replication population. MAIN CONCLUSIONS We demonstrated, for the first time, an association data with the PB form for a gene located on chromosome 10. In addition, we reported the association of TGFB1 gene with the MB form. Our results place these genes as candidates for validation and replication studies in leprosy polarisation.
Summary
This study evaluated the immune response of nude and BALB/c mice inoculated in the footpads (FP) with Mycobacterium leprae after 3, 5 and 8 months. At each timepoint peritoneal cells, ...peripheral blood, FP and popliteal lymph nodes (PLN) were collected. Peritoneal cell cultures were performed to measure the H2O2, O2−, NO, IL‐2, IL‐4, IL‐10, IL‐12, IFN‐γ and TNF levels. Serum levels of anti‐PGL‐I antibodies were also quantified. The results showed that the infection was progressive in nude mice with bacterial multiplication, development of macroscopic lesions in the FP and presence of bacilli in the PLN at 8 months. In BALB/c mice, the infection reached a plateau of bacillary multiplication at 5 months and regressed at 8 months. Histopathological analysis of FP revealed a mononuclear inflammatory infiltrate with a large number of neutrophils at 5 months, with a higher number in nude mice. At 8 months, the number of neutrophils decreased and the infiltrate was predominantly mononuclear in both mouse strains. There was no H2O2, O2−, IL‐2, IL‐4, IL‐10 and IFN‐γ production in the course of infection in nude mice; however, in BALB/c, O2− and IL‐12 production was higher at 5 months and NO, IFN‐γ and TNF production was higher at 8 months when there was a decrease in the number of bacilli. The level of anti‐PGL‐I antibodies was higher in BALB/c mice. Thus, nude and BALB/c mice can be used as experimental models for the study of various aspects of leprosy.
Studies investigating the immunopathological aspects of Jorge Lobo's disease have shown that the inflammatory infiltrate consists mainly of histiocytes and multinucleated giant cells involving ...numerous yeast-like cells of Lacazia loboi, with the T lymphocytes more common than B lymphocytes and plasma cells. The quantification of cytokines in peripheral blood mononuclear cells culture supernatant has revealed alterations in the cytokines profile, characterized by predominance of a Th2 profile. In view of these findings and of the role of cytokines in cell interactions, the objective of the present study was to investigate the presence of the cytokines IL-10, TGF-ß1 and TNF-α, as well as iNOS enzyme in granulomas induced by L. loboi. Histological sections obtained from skin lesions of 16 patients were analyzed by immunohistochemistry for the presence of these cytokines and iNOS. The results showed that TGF-ß1 was the cytokine most frequently expressed by cells present in the inflammatory infiltrate, followed by IL-10. There was a minimum to discrete positivity of cells expressing TNF-α and iNOS. The results suggest that the presence of immunosuppressive cytokines in skin lesions of patients with the mycosis might be responsible for the lack of containment of the pathogen as demonstrated by the presence of numerous fungi in the granuloma.
Angiogenesis and lymphangiogenesis are the processes of neovascularization that evolve from preexisting blood and lymphatic vessels. There are few studies on angiogenesis and none on ...lymphangiogenesis in leprosy. Thus, the role of neovascularization in the pathophysiological mechanisms of the disease was studied across the spectrum of leprosy, its reactional states and its residual lesions.
Seventy-six biopsies of leprosy skin lesions and seven healthy controls were selected. Fifty-five serum samples were used for the detection of CD105 by ELISA. Histological sections were stained with antibodies against CD31 (blood and lymphatic vessels), D2-40/podoplanin (lymphatic vessels), and CD105/endoglin (neovessels). Microvessels were counted in 100 high-power fields (400x) and the number of vessels was evaluated in relation to the extension of the inflammatory infiltrate (0-3), to the bacillary index (0-6) and to the clinical forms. Angiogenesis, as marked by CD31 and CD105, was observed across the leprosy spectrum, compared with the controls. Additionally, there was a positive correlation between these markers with extension of the infiltrate (p <0.0001). For D2/40, lymphangiogenesis was observed in the tuberculoid form (p <0.0001). There was no statistical significance for values of CD105 detected in plasma by ELISA.
Angiogenesis is present across the spectrum of leprosy and in its reactional forms. The increase in the number of vessels, as detected by CD31 and CD105 staining, is related to the extension of the inflammatory infiltrate. Samples from reactional lesions have a higher number of CD31+ and CD105+ stained vessels, which indicates their involvement in the pathophysiological mechanisms of the reactional states. The regression of lesions is accompanied by the regression of neovascularization. Drugs inhibiting angiogenesis may be relevant in the treatment of leprosy, in addition to multidrugtherapy, and in the prevention of the development of reactions.
Lacazia loboi is an uncultivated fungal pathogen of humans and dolphins that causes cutaneous and subcutaneous infections only in the tropical areas of the Americas. It was recently found by ...phylogenetic analysis that this unusual pathogen is closely related to Paracoccidioides brasiliensis and to the other fungal dimorphic members of the order ONYGENALES: That original phylogenetic study used universal primers to amplify well-known genes. However, this approach cannot be applied to the study of other proteins. We have developed a strategy for studying the gene encoding the gp43 homologous protein of P. brasiliensis in L. loboi. The gp43 protein was selected because it has been found that this P. brasiliensis antigen strongly reacts when it is used to test sera from patients with lacaziosis. The principle behind this idea was to obtain the gp43 amino acid sequence of P. brasiliensis and other homologous fungal sequences from GenBank and design primers from their aligned conserved regions. These sets of primers were used to amplify the selected regions with genomic DNA extracted from the yeast-like cells of L. loboi from experimentally infected mice. Using this approach, we amplified 483 bp of the L. loboi gp43-like gene. These sequences had 85% identity at the nucleotide level and 75% identity with the deduced amino acid sequences of the P. brasiliensis gp43 protein. The identity of the 483-bp DNA fragment was confirmed by phylogenetic analysis. This analysis revealed that the L. loboi gp43-like deduced amino acid sequence formed a strongly supported (100%) sister group with several P. brasiliensis gp43 sequences and that this taxon in turn was linked to the other fungal sequences used in this analysis. This study shows that the use of a molecular model for investigation of the genes encoding important proteins in L. loboi is feasible.
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We synthesized a series of novel dapsone–thalidomide hybrids (3a–i) by molecular hybridization and evaluated their potential for the treatment of type 2 leprosy reactions. All of the ...compounds had analgesic properties. Compounds 3c and 3h were the most active antinociceptive compounds and reduced acetic acid-induced abdominal constrictions by 49.8% and 39.1%, respectively. The hybrid compounds also reduced tumor necrosis factor-α levels in lipopolysaccharide-stimulated L929 cells. Compound 3i was the most active compound; at concentrations of 15.62 and 125μM, compound 3i decreased tumor necrosis factor-α levels by 86.33% and 87.80%, respectively. In nude mice infected with Mycobacterium leprae in vivo, compound 3i did not reduce the number of bacilli compared with controls. Compound 3i did not have mutagenic effects in Salmonella typhimurium strains TA100 and TA102, with or without metabolic activation (S9 mixture). Our results indicate that compound 3i is a novel lead compound for the treatment of type 2 leprosy reactions.
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