The use of different concentrations of leishmanial antigen in skin testing to evaluate delayed hypersensitivity in american cutaneous leishmaniasis

A review of the leishmanin skin test: A neglected test for a neglected disease

The leishmanin skin test (LST) has been used for decades to detect exposure and immunity to the parasite Leishmania, the causative agent of the neglected tropical disease leishmaniasis. In the LST, Leishmania antigen (leishmanin) is intradermally injected into the forearm. In an individual who has been previously infected, a delayed-type hypersensitivity (DTH) reaction results in a measurable induration at the site of the injection, indicating that previous exposure to Leishmania has resulted in the development of cell-mediated immunity. LST positivity is associated with long-lasting protective immunity against reinfection, most notably as reported for visceral leishmaniasis (VL). Despite efforts over the past few decades, leishmanin antigen is no longer produced under good manufacturing practice (GMP) conditions anywhere in the world. Consequently, the use of the LST in epidemiological studies has declined in favor of serological and molecular tests. In this review, we provide a historical overview of the LST and justification for the reintroduction of leishmanin. A GMP-grade leishmanin can be used to detect immunity in vivo by the LST and can be investigated for use in an interferon-γ release assay (IGRA), which may serve as an in vitro version of the LST. The LST will be a valuable tool for surveillance and epidemiological studies in support of the VL elimination programs and as a surrogate marker of immunity in vaccine clinical trials.

Reappraisal of Leishmanin Skin Test (LST) in the management of American Cutaneous Leishmaniasis: A retrospective analysis from a reference center in Argentina

Leishmania (Viannia) braziliensis is the species most frequently implicated with cutaneous and mucosal leishmaniasis in the Americas; its diagnosis is based on the identification of amastigotes in lesions, which is limited by low parasite burden. Leishmanin Skin Test (LST) is a support tool for diagnosis, based on delayed type hypersensitivity responses to Leishmania antigens injected intradermally, used in endemic areas as a complement to diagnosis. A retrospective analysis of individuals evaluated for their first episode of tegumentary leishmaniasis at a reference center in Argentina during the period 2006-2015 was performed, with the goal of assessing its usefulness as a support tool in the diagnosis of leishmaniasis. Demographic, clinical and diagnostic work-up were analyzed in individuals with clinically compatible lesions, lesion`s smear and LST. A total of 733 cases that met the case definition were included in the analysis; 678 (93%) localized cutaneous cases, 50 (7%) with mucosal involvement and 5 (<1%) disseminated. Diagnostic confirmation was reached in 474 (65%) cases through positive smears from skin or mucosal lesions, with only 6 cases among this group having negative LST. Among smear negative cases, 190 were negative also by LST, but in 69 instances LST was positive. Across age groups, similar ratios of sensitivity between smear and LST were calculated. Lesions older than 21 days-old were found to correlate with positive results both for smear and LST significantly more than younger lesions. These findings support the clinical use of LST as a diagnostic complement for American Cutaneous Leishmaniasis across all age groups even in endemic areas. In this analysis, the correlation with smear was high. Standardization of this technique and further research into its most adequate preparation and utilization protocols across different sites will help in the management of suspicious clinical cases.

Sporotrichoid leishmaniasis: a cross-sectional clinical, epidemiological and laboratory study in Rio de Janeiro State, Brazil

Background

Atypical presentations of cutaneous leishmaniasis include sporotrichoid leishmaniasis (SL), which is clinically described as a primary ulcer combined with lymphangitis and nodules and/or ulcerated lesions along its pathway.

Aims

To assess the differences between patients with sporotrichoid leishmaniasis and typical cutaneous leishmaniasis (CL).

Methods

From January 2004 to December 2010, 23 cases of SL (4.7%) were detected among 494 CL patients diagnosed at a reference center for the disease in Rio de Janeiro State, Brazil. These 23 cases were compared with the remaining 471 patients presenting CL.

Results

SL predominated in female patients (60.9%, p = 0.024), with older age (p = 0.032) and with lesions in upper limbs (52.2%, p = 0.028). CL affected more men (64.5%), at younger age, and with a higher number of lesions exclusively in lower limbs (34.8%).

Conclusions

Differences in clinical and epidemiological presentation were found between SL patients as compared to CL ones, in a region with a known predominance of Leishmania (Viannia) braziliensis. The results are similar to the features of most of the sporotrichosis patients as described in literature, making the differential diagnosis between ATL and sporotrichosis more important in overlapping areas for both diseases, like in Rio de Janeiro State.

Induction of Early Autophagic Process on Leishmania amazonensis by Synergistic Effect of Miltefosine and Innovative Semi-synthetic Thiosemicarbazone

Drug combination therapy is a current trend to treat complex diseases. Many benefits are expected from this strategy, such as cytotoxicity decrease, retardation of resistant strains development, and activity increment. This study evaluated in vitro combination between an innovative thiosemicarbazone molecule – BZTS with miltefosine, a drug already consolidated in the leishmaniasis treatment, against Leishmania amazonensis. Cytotoxicity effects were also evaluated on macrophages and erythrocytes. Synergistic antileishmania effect and antagonist cytotoxicity were revealed from this combination therapy. Mechanisms of action assays were performed in order to investigate the main cell pathways induced by this treatment. Mitochondrial dysfunction generated a significant increase of reactive oxygen and nitrogen species production, causing severe cell injuries and promoting intense autophagy process and consequent apoptosis cell death. However, this phenomenon was not strong enough to promote dead in mammalian cell, providing the potential selective effect of the tested combination for the protozoa. Thus, the results confirmed that drugs involved in distinct metabolic routes are promising agents for drug combination therapy, promoting a synergistic effect.

Fatores associados ao insucesso do tratamento da leishmaniose cutânea com antimoniato de meglumina

Foram investigados os fatores associados ao insucesso do tratamento da leishmaniose cutânea com antimoniato de meglumina num serviço de referência para leishmanioses, em Mato Grosso. Uma coorte histórica de 151 pacientes com diagnóstico de leishmaniose cutânea foi construída com informações dos prontuários. A incidência de insucesso após o primeiro ciclo de antimonial foi 47% (IC95%=39,2%-55%). Dose de antimonial inferior a 10mg/kg/dia (RR=1,8; IC95:1,1-3,0), tratamento prévio para leishmaniose (RR=1,7; IC95:1,3-2,4), três ou mais lesões (RR=1,9; IC95:1,4-2,5), tratamento irregular (RR=1,9; IC95:1,3-2,6) e peso maior que 68kg (RR=1,7; IC95:1,1-2,5) foram associados ao insucesso terapêutico. Após ajuste, permaneceram associados ao insucesso os seguintes fatores: 3 ou mais lesões cutâneas (OR=4,6; IC95%=1,2-17,4), tratamento anterior para leishmaniose tegumentar americana (OR=4,5; IC95%=1,1-7,5), peso maior que 68kg (OR=4,3; IC95%=1,5-11,9) e irregularidade no tratamento (OR=12,5; IC95%=2,1-75,4), embora o peso possivelmente tenha sido associado ao insucesso devido à limitação da dose máxima. Estes achados auxiliam na identificação de pacientes com maior risco de insucesso no tratamento da leishmaniose cutânea com antimonial.

[Montenegro intradermoreaction after the test sequential repetitions in Porteirinha, Minas Gerais State, Brazil]

With the purpose of evaluating the response of sequential applications of Montenegro intradermoreaction (IDRM), we have repeated four times the test in the inhabitants of an endemic area for kala-azar, that resulted negative 3-4 years ago. Firstly, we have repeated three IDRM in those who remained negative, with a 60-day interval among them. In the second stage, we have performed a last reaction in all participants of the study. From the total of 49 individuals with prior negative IDRM, 19 (38.8%) have positivated the test in some of the times, 17 (34.7%) have given up the study and 13 (26.5%) remained with a negative result in all the applications. In the second stage, the repetition of IDRM has shown that from the 14 positive in some of the tests, 8 remained like this and 6 have become negative. Our results confirm the possibility of late hypersensitivity induction in some individuals as a consequence of IDRM application.

Risk factors associated with asymptomatic infection by Leishmania chagasi in north-east Brazil

Various factors have been associated with a predisposition to the development of clinical American visceral leishmaniasis (AVL). However, little information is available about the factors that predispose to asymptomatic infection. To identify the risk factors associated with asymptomatic infection, a study was carried out between July 1997 and June 1998 on children aged 0-5 years in the districts of Vila Nova and Bom Viver in the municipality of Raposa in the island of São Luís, State of Maranhão, Brazil. A questionnaire containing socioeconomic, demographic and epidemiological data was used. The delayed-type hypersensitivity (DTH) test was carried out on 639 children in the first phase, and on 572 in the second, 7 months after the first survey, using Leishmania amazonensis antigen. Infection was determined by enzyme-linked immunosorbent assay (ELISA) in 638 children during the first phase, and in 572 during the second. Six outcome measures were used: initial prevalence, final prevalence and incidence, each determined by DTH and ELISA. The incidence of infection was 10.8% when determined by DTH and 28.5% when determined by ELISA. After adjustment for confounding variables using Cox regression, infection by L. chagasi was associated with child's age (> or = 2 years), location of the dwellings (Vila Nova) and reporting of relatives with AVL. Bathing outside the house and playing outdoors between 18:00 and 20:00 were identified as risk factors in some analyses but not in others. Presence of intra- and peridomestic Lutzomyia sandflies and animals such as dogs or chickens in the house or in the neighbourhood appeared as risk factors in some analyses but in others they unexpectedly seemed to protect from infection. Malnutrition was not found to be associated with infection.

[Evaluation of the sensitization power of Montenegro skin test]

The Montenegro skin test, used to diagnose cutaneous leishmaniasis, is now being considered to detect immunogenicity after vaccination. In this study, we evaluated the ability of this test to induce immune response and IFN-g production in subjects not previously exposed to Leishmania. The Montenegro skin test was performed using antigens of L. amazonensis produced by our laboratory (group I) or by FIOCRU-RJ (group II). At day 30, 33% of the subjects from group I and 42% from group II were positive, compared to 67% from group I and 50% from group II at day 90. IFN-y was detected in 56 % of subjects from group I and 17% from group II at day 30 (169+/-309 and 11+/-36pg/ml) and in 67% from group I and 58% from group II by day 360 (69+/-107 and 18+/-20pg/ml). These data demonstrate that the Montenegro skin test induces not only a delayed hypersensitivity reaction, but also IFN-y production.

AIDS in Latin America

The epidemic in Latin America has placed an unexpected additional burden on the health care systems and national economies, already weak and affected by severe problems. Specific regional diseases in addition to common opportunistic infections, and particularly the high incidence of TB, produce a different picture compared with the United States and Europe. Access to ARV therapy is far from being universal in Latin America; nevertheless, some countries are providing HAART to all eligible patients, showing that it is not impossible to improve quality of care for people living with HIV infection in the region. Before assuming as definitive and irreversible that at least one or two generations will be sacrificed on the altar of inequity of our uneven world, we as acting scientists should join the struggle of millions of human beings claiming their right to be treated with the best drugs that science can offer today.

Human cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in Santiago del Estero, Argentina: identification of parasites by monoclonal antibodies and isoenzymes

Diagnostic and parasite characterization and identification studies were carried out in human patients with cutaneous leishmaniasis lesions in Santiago del Estero, Northern Province of Argentina. Diagnostic procedures were biopsies of lesions for smears and inoculations in hamster, needle aspirations of material from ulcers for "in vitro" cultures. Immunodiagnostic techniques applied were IFAT-IgG and Montenegro skin test. Primary isolation of eight stocks of leishmanial parasites was achieved from patients with active lesions. All stocks were biologically characterized by their behaviour in hamster, measurements of amastigote and promastigotes and growth "in vitro". Eight stocks were characterized and identified at species level by their reactivity to a cross-panel of sub-genus and species-specific Monoclonal Antibodies through an Indirect Immunofluorescence technique and a Dot-ELISA. We conclude from the serodeme analysis of Argentina stocks that: stocks MHOM/AR/92/SE-1; SE-2; SE-4; SE-8; SE-8-I; SE-30; SE-34 and SE-36 are Leishmania (Viannia) braziliensis. Three Leishmania stocks (SE-1; SE-2 and SE-30) did not react with one highly species-specific Monoclonal Antibody (Clone: B-18, Leishmania-(Viannia) braziliensis marker) disclosing two serodeme group patterns. Five out of eight soluble extracts of leishmanial promastigotes were electrophoresed on thin-layer starch gels and examined for the enzyme MPI, Mannose Phosphate Isomerase; MDH, Malate Dehydrogenase; 6PGD, 6 Phosphogluconate Dehydrogenase; NH, Nucleoside Hydrolase, 2-deoxyinosine as substrate; SOD, Superoxide Dismutase; GPI, Glucose Phosphate Isomerase and ES, Esterase. From the isoenzyme studies we concluded that stocks: MHOM/AR/92/SE-1; SE-2; SE-4; SE-8 and SE-8-I are isoenzymatically Leishmania (Viannia) braziliensis. We need to analyze more enzymes before assigning them to a braziliensis zymodeme.

[Comparative study of meglumine antimoniate, pentamidine isethionate and aminosidine sulfate in the treatment of primary skin lesions caused by Leishmania (Viannia) braziliensis]

With the aim of comparing the therapeutic efficacy, tolerability and toxicity of meglumine antimoniate, aminosidine sulphate and pentamidine isethionate, a field study was conducted on randomized treatment of patients with primary cutaneous leishmaniasis due to Leishmania (Viannia) braziliensis (L(V)b), in Corte de Pedra, BA, from October 1992 up to January 1993. Forty six patients were treated and distributed into three groups, two with 15 and one with 16 subjects. All patients were submitted to clinical examination, histopathological and immunological investigations, as diagnostic criterium. All patients were treated by intramuscular route. Group 1 received pentamidine 4 mg/kg/every 2 days, for 8 applications; Group 2 received aminosidine 20 mg/kg/day, for 20 days, and Group 3 received meglumine 10 mg Sbv/kg/day, for 20 days. Failure of therapy was defined as ulceration of the skin lesion four months after treatment. Such failure occurred in five cases as follows: two cases in patients of group 1 one case in patients of group 2, and two cases in group 3, after the first year of follow up. In the evaluation after three years we reviewed fifteen patients, five in each group; except for one in Group 3, all of them were cured. Statistical significance of the results between the three schedules used was not verified.

Serodiagnosis of leishmaniasis

Leishmaniasis is a spectrum of diseases ranging in severity from cutaneous (CL), post-kala-azar dermal (PKDL), and diffuse cutaneous (DCL) to mucocutaneous (MCL) and visceral (VL) infections that are endemic in 86 tropical and subtropical countries around the world, accounting for 75,000 deaths per year. Different forms of leishmaniases are generally caused by different distinct species of Leishmania having a digenetic life cycle alternating between an aflagellated amastigote form replicative within the macrophages of the host and a flagellated promastigote form that multiplies within the gut of the sandfly. VL, MCL, PKDL, DCL, and CL forms of the disease can be arranged on a priority basis in accordance with the humoral immune responses of host. Generally, the cell-mediated immunity, particularly the delayed-type hypersensitivity to leishmanial antigens, is associated with CL, MCL, PKDL, and cured VL cases. The serodiagnosis of leishmaniasis appears to be an alternative to parasite detection in biopsy samples either by the staining of amastigotes or by culturing the amastigotes, which transform to a promastigote form and replicate. A battery of immunological procedures have been developed or adapted to demonstrate either humoral or cell-mediated immune responses against Leishmania for diagnosis and epidemiological survey. The sensitivity and specificity of such diagnostic methods depend on the type, source, and purity of antigen employed, as some of the leishmanial antigens have common cross-reactive epitopes shared with other microorganisms, particularly Trypanosoma, Mycobacteria, Plasmodia, and Schistosoma. Serodiagnostic techniques for the detection of antileishmanial antibodies have been employed with about 72 to 100, 23 to 90, 83, and 33 to 100% success in VL, CL, MCL, and PKDL patients, respectively. The Leishmanin skin test (LST) is useful to detect MCL and CL, with about 100 and 84% success, respectively. In PKDL, the gradual fall of antileishmanial antibody titer to some extent and the rise of delayed hypersensitivity to the parasite antigen are the characteristic features associated with the chronicity of the disease. The use of whole promastigote as the source of antigens in the direct agglutination test (DAT) and immunofluorescent test (IFAT) gave cross-reactions with the sera of leprosy, tuberculosis, and African trypanosomiasis patients. Again, the use of cell-free extracts of promastigotes generally gave false positive results with the sera of normal human and Chagas' disease, leprosy, tuberculosis, and malaria patients in enzyme-linked immunosorbent assay (ELISA), dot ELISA, immunodiffusion, immunoelectrophoresis, and counter-current immunoelectrophoresis tests.(ABSTRACT TRUNCATED AT 400 WORDS)

Cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis in Amazonian Brazil, and the significance of a negative Montenegro skin-test in human infections

The clinical and epidemiological features of 62 cases of cutaneous leishmaniasis due to Leishmania (Leishmania) amazonensis, from Pará State, Amazonian Brazil, are discussed. The parasite, isolated in hamster skin and/or blood-agar culture medium, was in each case identified by both biological characteristics and a monoclonal antibody specific for promastigotes of L. (L.) amazonensis. Of the 62 patients, 46 (74.2%) presented with a single cutaneous lesion, and on no occasion was evidence found indicating metastatic spread to either the naso-pharyngeal mucosae or the viscera. Recent claims that this parasite may be responsible for both mucocutaneous leishmaniasis and typical visceral leishmaniasis are discussed. Meglumine antimoniate (Glucantime) proved highly efficient in the treatment of all patients. Of the 62 patients examined by the Montenegro skin test, only 32 (51.6%) gave a positive reaction. The significance of this finding is considered and the hypothesis made that the parasite itself may induce an immunoinhibition. Field studies amply confirmed the role of Lutzomyia flaviscutellata as the major sandfly vector of L. (L.) amazonensis in Amazonia.

[Cutaneous leishmaniasis in the Western region of the State of Santa Catarina, Brazil]

A survey was performed among 22 patients with ulcers suspected of leishmanial origin in the municipalities of Quilombo and Coronel Freitas, west of Santa Catarina State. From 5 patients only smears from the ulcers were examined, 5 others were submitted to Montenegro's intradermal test and in 8 both methods were used. Cases were regarded as confirmed when: 1. parasites were found in the ulcer smears; 2. the lesions were clinically characteristic and the skin test was positive and 3. the clinically characteristic lesions healed after specific treatment. Fourteen patients were regarded as confirmed cases, 11 being autochthonous, showing that transmission of cutaneous leishmaniasis occurs in the State. Of the autochthonous cases 5 showed parasites in the skin smears. Most patients were males and all were older than 15 years of age.

Mucosal leishmaniasis ("espundia" Escomel, 1911)

One of the more serious clinical forms of leishmaniasis occurs in espundia when the mucosae of the upper respiratory passages are inflamed. This complication is a metastasis from a skin lesion caused by Leishmania braziliensis braziliensis (Lbb) although cases have been described associated with other leishmanial species. Epidemiological data suggest that a detectable mucosal metastasis occurs in fewer than 5% of patients infected with Lbb in our study area. The determinants of this complication are still largely obscure. The granuloma usually commences on the nasal septum. In about two-thirds of our patients the lesion remained restricted to the nose. In the rest the pharynx, palate, larynx and lips were involved, in this order. It is often difficult to isolate the parasite and for routine diagnosis the leishmanin skin reaction and serological tests are helpful. Although a serious condition, with possible mutilation and even death as subsequent complications, treatment is still mainly with pentavalent antimonials, introduced 40 years ago. These are most unsatisfactory for field use, being given parenterally and relatively toxic. In mucosal leishmaniasis, if sufficient antimony can be administered in a regular daily dose, the relapse rate is small (3 of 42 patients followed for a mean of 5 years). Also, antimony treatment of the initial skin ulcer due to Lbb followed for a mean of 4 years of 83 patients resulted in subsequent mucosal metastasis in only 2. Since espundia is relatively rare, specific treatment targeted to this specific problem is the efficient short term solution. At present there is no satisfactory alternative drug to those in current use.