Immunotherapy and immunochemotherapy in visceral leishmaniasis : promising treatments for this neglected disease.

Leishmaniasis has several clinical forms: self-healing or chronic cutaneous leishmaniasis or post-kala-azar dermal leishmaniasis; mucosal leishmaniasis; visceral leishmaniasis (VL), which is fatal if left untreated.The epidemiology and clinical features of VL vary greatly due to the interaction of multiple factors including parasite strains, vectors, host genetics, and the environment. Human immunodeficiency virus infection augments the severity of VL increasing the risk of developing active disease by 100?2320 times. An effective vaccine for humans is not yet available. Resistance to chemotherapy is a growing problem in many regions, and the costs associated with drug identification and development, make commercial production for leishmaniasis, unattractive.The toxicity of currently drugs, their long treatment course, and limited efficacy are significant concerns. For cutaneous disease, many studies have shown promising results with immunotherapy/immunochemotherapy, aimed to modulate and activate the immune response to obtain a therapeutic cure. Nowadays, the focus of many groups centers on treating canine VL by using vaccines and immunomodulators with or without chemotherapy. In human disease, the use of cytokines like interferon-g associated with pentavalent antimonials demonstrated promising results in patients that did not respond to conventional treatment. In mice, immunomodulation based on monoclonal antibodies to remove endogenous immunosuppressive cytokines (interleukin-10) or block their receptors, antigen-pulsed syngeneic dendritic cells, or biological products like Pam3Cys (TLR ligand) has already been shown as a prospective treatment of the disease. This review addresses VL treatment, particularly immunotherapy and/or immunochemotherapy as an alternative to conventional drug treatment in experimental models, canine VL, and human disease

Sensitive and specific serodiagnosis of Leishmania infantum infection in dogs by using peptides selected from hypothetical proteins identified by an immunoproteomic approach

In Brazil, the percentage of infected dogs living in areas where canine visceral leishmaniasis (CVL) is endemic ranges from 10 to 62%; however, the prevalence of infection in dogs is probably higher than figures reported from serological studies. In addition, problems with the occurrence of false-positive or false-negative results in the serodiagnosis of CVL have been reported. The present work analyzed the potential of synthetic peptides mapped from hypothetical proteins for improvement of the serodiagnosis of Leishmania infantum infection in dogs. From 26 identified leishmanial proteins, eight were selected, considering that no homologies between these proteins and others from trypanosomatide sequence databases were encountered. The sequences of these proteins were mapped to identify linear B-cell epitopes, and 17 peptides were synthesized and tested in enzyme-linked immunosorbent assays (ELISAs) for the serodiagnosis of L. infantum infection in dogs. Of these, three exhibited sensitivity and specificity values higher than 75% and 90%, respectively, to differentiate L. infantum-infected animals from Trypanosoma cruziinfected animals and healthy animals. Soluble Leishmania antigen (SLA) showed poor sensitivity (4%) and specificity (36%) to differentiate L. infantum-infected dogs from healthy and T. cruzi-infected dogs. Lastly, the three selected peptides were combined in different mixtures and higher sensitivity and specificity values were obtained, even when sera from T. cruzi-infected dogs were used. The study’s findings suggest that these three peptides can constitute a potential tool for more sensitive and specific serodiagnosis of L. infantum infection in dogsThis work was supported by grants from the Pró-Reitoria de Pesquisa from UFMG (Edital 07/2012), Instituto Nacional de Ciência e Tecnologia em Nano-biofarmacêutica (INCT-NANOBIOFAR, Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) (CBB-APQ-02364-08, CBB-APQ-00356-10, CBB-APQ-00496-11, and CBB-APQ-00819-12), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (APQ-472090/2011-9), and the Instituto Nacional de Ciência e Tecnologia em Vacinas (INCT-V). E.A.F.C. and A.P.F. are CNPq grant recipients. M.A.C.-F. is a FAPEMIG/CAPES grant recipient. This study was supported in Spain, in part, by grants from the Ministerio de Ciencia e Innovación (FIS/PI1100095)

Do leishflow ao leishplex : inovações tecnológicas da sorologia por citometria de fluxo aplicada ao diagnóstico da Leishmaniose Visceral Canina.

Programa de Pós-Graduação em Ciências Farmacêuticas. CIPHARMA, Escola de Farmácia, Universidade Federal de Ouro Preto.Os ensaios sorológicos para Leishmania são determinantes para indicar a eutanásia de cães como medida de controle da Leishmaniose Visceral no Brasil. No presente estudo, buscou-se avaliar o desempenho das metodologias sorológicas que atualmente são – e os que já foram – adotadas pelo Ministério da Saúde do Brasil (DPP, ELISA e RIFI), assim como o da sorologia por Citometria de Fluxo (CF), no diagnóstico da Leishmaniose Visceral Canina (LVC). Os ensaios foram conduzidos em uma ampla variedade de amostras de soro, que incluiu cães naturalmente infectados por Leishmania infantum portadores de diferentes formas clínicas, cães infectados com outras protozooses caninas (L. braziliensis, Trypanosoma cruzi, Ehrlichia canis e Babesia canis) e cães vacinados contra LVC (Leishmune®, Leish-Tec® e LBSap). Em relação aos testes oficiais, o principal achado se deu pela elevada especificidade do DPP (99,4%) em relação à ELISA (89,9%) e RIFI (75,2%). Quanto ao teste LeishFlow, destacou-se a sensibilidade de 95,0% tanto nos cães assintomáticos, quanto nos oligossintomáticos e sintomáticos. A especificidade do LeishFlow em amostras de soro de cães infectados por L. braziliensis foi de 80,0%, 55,6% nas amostras de T. cruzi, 93,3% em E. canis, e 100,0% em B. canis. Nos cães vacinados pela Leishmune®, Leish-Tec® e LBSap observou-se 100,0% de especificidade. A sequência do trabalho buscou o desenvolvimento de uma inovação metodológica na sorologia por CF por meio do acoplamento de antígenos recombinantes à microesferas de poliestireno. Os antígenos multiepitopo PQ20 e C1, e os recombinantes rLci1A e rLci2B foram acoplados a diferentes microesferas, formando os sistemas antigênicos microesfera–proteína C6–PQ20, E7–C1, A4–rLci1A, e E4–rLci2B. Constatou-se que os sistemas A4−rLci1A e E4−rLci2B foram os únicos que se mostraram adequadamente funcionais para a pesquisa de anticorpos caninos IgG. O ensaio sorológico pelo sistema A4−rLci1A apresentou sensibilidade de 85,0% nos cães assintomáticos, e 95,0% nos oligossintomáticos e sintomáticos. A especificidade deste sistema nos cães infectados por L. braziliensis foi de 100,0%, enquanto que nas infecções por E. canis e B. canis, esse valor foi de 30,0% e 20,0% respectivamente. Nos cães vacinados por Leishmune® e Leish-Tec® a especificidade foi de 70,0%, e por LBSap de 80,0%. O sistema antigênico E4−rLci2B, por sua vez, apresentou sensibilidade de 85,0% nos animais assintomáticos, e de 100,0% nos oligossintomáticos e sintomáticos. A especificidade deste sistema em relação as infecções por L. braziliensis e E. canis foi de 80,0%, e de 60,0% quanto a infecção por B. canis. A especificidade relacionada à vacinação por Leishmune® e pela Leish-Tec® foi de 90,0%, e na LBSap foi de 50,0%. A combinação dos sistemas A4−rLci1A e E4−rLci2B para o ensaio sorológico único, LeishPlex, apresentou sensibilidade de 85,0% nos cães assintomáticos, e 100,0% nos grupos oligossintomático e sintomático. A especificidade em cães infectados por L. braziliensis foi de 100,0%, enquanto que em E. canis foi de 70,0%, e em B. canis foi 60,0%. Nos cães vacinados pela Leishmune®, Leish-Tec® e LBSap observou-se 100,0% de especificidade. Portanto, a inovação LeishPlex resultou em uma elevação da precisão geral de acertos. O conjunto de dados evidenciados no presente trabalho fortalecem a sorologia por CF como uma importante abordagem para o diagnóstico sorológico da LVC.Serologic tests for Leishmania are key to determine the euthanasia of infected dogs as a control measure of Visceral Leishmaniasis in Brazil. In the present study, we sought to evaluate the performance of serologic methods that are currently – and those that have already been – adopted by the Ministry of Health of Brazil (DPP, ELISA and IFAT), as well as the serology by Flow Cytometry (FC), in the diagnosis of Canine Visceral Leishmaniasis (CVL). The tests were conducted in a wide variety of serum samples, that included dogs naturally infected with Leishmania infantum with different clinical forms, dogs infected with other canine protozoosis (L. braziliensis, Trypanosoma cruzi, Ehrlichia canis and Babesia canis), and vaccinated against CVL (Leishmune®, Leish-Tec® and LBSap). Regarding the official tests, the main finding was associated to the high specificity of the DPP (99.4%) in relation to ELISA (89.9%) and IFAT (75.2%). For the LeishFlow test, it was worth noting a sensitivity of 95.0% in all asymptomatic, oligosymptomatic and symptomatic dogs. The specificity of LeishFlow in serum samples of dogs infected with L. braziliensis was 80.0%, 55.6% in T. cruzi, 93.3% in E. canis, and 100.0% in B. canis. In the dogs vaccinated with Leishmune®, Leish-Tec® and LBSap, 100.0% of specificity was observed. The next step of the work sought the development of an innovative approach in FC serology by coupling recombinant antigens to polystyrene beads. The multiepitope antigens PQ20 e C1, and the recombinants rLci1A e rLci2B were coupled to different beads generating the antigenic systems C6–PQ20, E7–C1, A4–rLci1A and E4–rLci2B. It was observed that the systems A4–rLci1A and E4–rLci2B were the only ones that were properly functional to the research of IgG canine antibodies. The serological assay by the system A4–rLci1A presented sensitivity of 85,0% in the asymptomatic dogs, and 95,0% in the oligosymptomatic and symptomatic ones. The specificity of this system in dogs infected by L. braziliensis was 100,0%, whereas in E. canis and B. canis infections this value was 30,0% and 20,0% respectively. In dogs vaccinated with Leishmune® and Leish-Tec® the specificity was 70,0%, e with LBSap it was 80,0%. The antigenic system E4–rLci2B, in turn, showed sensitivity of 85,0% in asymptomatic animals, and of 100,0% in oligosymptomatic and symptomatic dogs. The specificity of this system concerning infections by L. braziliensis and E. canis was 80,0%, and 60,0% concerning the infection by B. canis. The specificity regarding the vaccination with Leishmune® and Leish-Tec® was 90,0%, and with LBSap it was 50,0%. The combination of the systems A4−rLci1A and E4−rLci2B for a single serological assay, LeishPlex, presented sensitivity of 85,0% in asymptomatic animals, and of 100,0% in oligosymptomatic and symptomatic dogs. The specificity in dogs infected by L. braziliensis was 100,0%, while in E. canis it was 70,0%, and 60,0% concerning the infection by B. canis. In the dogs vaccinated with Leishmune®, Leish-Tec® and LBSap, 100.0% of specificity was observed. Thus, the innovative LeishPlex yielded increased accuracy. The data set evidenced by the present work strengthened the FC serology as an important approach for CVL serological diagnosis

Desenvolvimento de um protótipo de kit para diagnóstico da leishmaniose visceral canina empregando a citometria de fluxo.

A leishmaniose visceral encontra-se em expansão em alguns centros urbanos sendo importante destacar o papel dos cães como reservatório da doença. Assim, o controle da leishmaniose visceral canina (LVC) torna-se relevante, sendo as ações preconizadas pelo ministério da saúde baseadas num tripé de ações que sugerem o tratamento dos casos humanos, combate ao vetor e a eutanásia dos cães soropositivos. No entanto, devido à limitação na eficiência dos testes de diagnósticos atualmente empregados (RIFI e ELISA), a eliminação destes cães torna-se cada vez mais difícil e questionável. Neste contexto, o presente projeto propôs desenvolver e validar um protótipo de kit de diagnóstico pela pesquisa de anticorpos anti-Leishmania fixada através da técnica de citometria de fluxo. Para cumprir com o objetivo, foram utilizados soros de cães naturalmente infectados, portadores de diferentes formas clínicas, provenientes da área endêmica de Belo Horizonte, e soros de cães não infectados do Centro de Ciência Animal (CCA) da UFOP. Na primeira etapa deste projeto, houve a produção de promastigotas de L. infantum que, em seguida, foram preservadas em diferentes conservantes (Fenol 0.35%, Formol 0.5%, Thimerosal 0.01% e controle PBS) e em diferentes condições de temperatura (25°C, 4°C e -20°C). Na etapa seguinte, a etapa de validação dos antígenos, foram realizadas avaliações mensais das condições de rendimento reacional, aspectos morfológicos e microbiológicos das diferentes preparações antigênicas. Estas análises revelaram que a condição ideal de preservação dos antígenos de L. infantum a serem empregados no protótipo de kit é a fixação por formol 0,5% e acondicionamento em geladeira. A última etapa deste estudo avaliou os índices de desempenho do protótipo empregando o suporte antigênico conservado em formol 0,5% e estocado em geladeira. Os resultados observados revelaram um excelente potencial do protótipo no diagnóstico da LVC, com valores de sensibilidade igual a 95%, especificidade de 100%, valor preditivo positivo de 100%, valor preditivo negativo igual a 83,3% e a acurácia do teste foi estimada em 96%. Desta forma, a partir deste trabalho, torna-se disponível uma nova alternativa para o diagnóstico sorológico da LVC, que poderá ser empregada em campanhas de controle da doença no Brasil.Visceral leishmaniasis is expanding in some urban centers and it is important to highlight the role of dogs as reservoirs of the disease. Therefore, the control of Canine Visceral Leishmaniasis (CVL) is important, and the Brazilian Ministry of Health established three pivotal actions that include the treatment of the human cases of the disease, vector control and the euthanasia of seropositive dogs. However, due to the limited efficiency of the diagnosis tests commonly used in serological trails (RIFI and ELISA), the elimination of these dogs becoming increasingly difficult and questionable. So, this project proposed the development and validation of a new diagnosis prototype kit employing the flow cytometry anti-fixed Leishmania infantum promastigotes as a novel serological device for laboratorial diagnosis of CVL. To achieve this goal, sera of naturally infected dogs that have different clinical forms from the endemic area of Belo Horizonte were used. In addition to these, sera of non-infected dogs maintained in the UFOP Animal Facilities were included as a control group. In the first step of this study, promastigotes of L. infantum were produced and kept in different preservative solutions (Phenol 0,35%, Formaldehyde 0,5%, Thimerosal 0,01% and PBS) and stored at different temperatures (25°C, 4°C e -20°C). Then, in the next stage to validate these antigens, evaluations of reaction yield, so as the morfologic and microbiologic features, were conduced monthly. These assessment showed that the best condition to preserve the antigenic support of the prototype was obtained when the promastigotes forms are put in Formaldehyde 0,5% at the refrigerator temperature (4°C). Lastly, the performance of the prototype was evaluated when those antigens were used. The results demonstrated an excellent potencial os this new method in the diagnosis of CVL. It is possible to observe great values of sensibility (95%), specificity (100%), positive and negative predictive values (100% and 83,3% respectively) so as de accuracy (96%). In conclusion, from this work, one alternative methodology is available for the CVL immunodiagnosis. The prototype may contribute

Risk profile for Leishmania infection in dogs coming from an area of visceral leishmaniasis reemergence.

Until the 1980s, visceral leishmaniasis was concentrated in poor rural areas of Brazil. The Vale do Rio Doce, located in the Southeastern Brazilian state of Minas Gerais, was an endemic area with high numbers of human and canine cases. Prophylactic measures adopted since the 1960s reduced the number of cases and the region became a ?controlled endemic? area. In the early 1990s, however, the program was interrupted, and the human disease reemerged in 2008. This cross-sectional study evaluated the prevalence and the risk profile of infection of dogs with Leishmania spp in this reemergence area of visceral leishmaniasis. Among a population of approximately 280,000 people, a total of 3835 dog owners were interviewed about socioeconomic conditions, housing, peridomicile features, and their dogs? characteristics and behavior. Blood samples were collected from 5822 dogs of an estimated canine population of 20,000 and anti-Leishmaniasis antibodies were identified using Dual-Path Platform and ELISA. We observed that 1282 of the 5822 dogs were seropositive for the protozoan indicating a seroprevalence of 22%. The risk factors associated with Leishmania infection in dogs were: non-paved backyard (OR 1.4; 95%CI 1.2?1.7); the presence of dry leaves and decaying fruit in the backyard (OR 1.3; 95%CI 1.1?1.5); medium-sized (OR 1.3; 95% 1.1?1.5) or big-sized dogs (OR 1.8; 95%CI 1.5?2.3); short-haired dogs (OR 1.8; 95%CI 1.5?2.1); dogs that slept in the backyard (OR 2.6; 95%CI 1.8?3.6) or in the balcony (OR 1.6; 95%CI 1.1?2.3); and history of canine visceral leishmaniasis in the household (OR 1.3; 95%CI 1.1?1.5). Our results suggest a strong reemergence of canine visceral leishmaniasis after the discontinuation of the control programs. Also, the observed risk factors reinforce the role of health education and environmental management measures to the effective control of the disease

Genetic homogeneity among Leishmania (Leishmania) infantum isolates from dog and human samples in Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil.

Background: Certain municipalities in the Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil, have the highest human visceral leishmaniasis (VL) mortality rates in the country and also demonstrate high canine seropositivity. In Brazil, the etiologic agent of VL is Leishmania (Leishmania) infantum. The aim of this study was to evaluate the intraspecific genetic variability of parasites from humans and from dogs with different clinical forms of VL in five municipalities of BHMA using PCR-RFLP and two target genes: kinetoplast DNA (kDNA) and gp63. Methods: In total, 45 samples of DNA extracted from clinical samples (n = 35) or L. infantum culture (n = 10) were evaluated. These samples originated from three groups: adults (with or without Leishmania/HIV co-infection; n = 14), children (n = 18) and dogs (n = 13). The samples were amplified for the kDNA target using the MC1 and MC2 primers (447 bp), while the Sg1 and Sg2 (1330 bp) primers were used for the gp63 glycoprotein target gene. Results: The restriction enzyme patterns of all the samples tested were monomorphic. Conclusions: These findings reveal a high degree of genetic homogeneity for the evaluated gene targets among L. infantum samples isolated from different hosts and representing different clinical forms of VL in the municipalities of BHMA studied

Molecular diagnosis of canine visceral leishmaniasis : a comparative study of three methods using skin and spleen from dogs with natural Leishmania infantum infection.

Polymerase chain reaction (PCR) and its variations represent highly sensitive and specificmethods for Leishmania DNA detection and subsequent canine visceral leishmaniasis (CVL)diagnosis. The aim of this work was to compare three different molecular diagnosis tech-niques (conventional PCR [cPCR], seminested PCR [snPCR], and quantitative PCR [qPCR])in samples of skin and spleen from 60 seropositive dogs by immunofluorescence antibodytest and enzyme-linked immunosorbent assay. Parasitological analysis was conducted byculture of bone marrow aspirate and optical microscopic assessment of ear skin and spleensamples stained with Giemsa, the standard tests for CVL diagnosis. The primers L150/L152and LINR4/LIN17/LIN19 were used to amplify the conserved region of the Leishmania kDNAminicircle in the cPCR, and snPCR and qPCR were performed using the DNA polymerasegene (DNA pol _) primers from Leishmania infantum. The parasitological analysis revealedparasites in 61.7% of the samples. Sensitivities were 89.2%, 86.5%, and 97.3% in the skin and81.1%, 94.6%, and 100.0% in spleen samples used for cPCR, snPCR, and qPCR, respectively.We demonstrated that the qPCR method was the best technique to detect L. infantum inboth skin and spleen samples. However, we recommend the use of skin due to the highsensitivity and sampling being less invasive

Genetic homogeneity among Leishmania (Leishmania) infantum isolates from dog and human samples in Belo Horizonte Metropolitan Area (BHMA); Minas Gerais; Brazil

Submitted by Nuzia Santos ([email protected]) on 2016-01-29T17:47:35Z No. of bitstreams: 1 Genetic homogeneity among Leishmania (Leishmania) infantum isolates.pdf: 10721186 bytes, checksum: 6344edd6cdea306724b13c911ba8a110 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2016-02-01T11:46:00Z (GMT) No. of bitstreams: 1 Genetic homogeneity among Leishmania (Leishmania) infantum isolates.pdf: 10721186 bytes, checksum: 6344edd6cdea306724b13c911ba8a110 (MD5)Made available in DSpace on 2016-02-01T11:46:00Z (GMT). No. of bitstreams: 1 Genetic homogeneity among Leishmania (Leishmania) infantum isolates.pdf: 10721186 bytes, checksum: 6344edd6cdea306724b13c911ba8a110 (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Pesquisas Clínicas. Belo Horizonte, MG, Brasil/Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Parasitologia. Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Pesquisas Clínicas. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Pesquisas Clínicas. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Parasitologia. Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias. Belo Horizonte, MG, Brasil/Universidade Federal de Minas Gerais. Faculdade de Medicina. Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical. Belo Horizonte, MG, Brasil/Universidade Federal de Ouro Preto. Escola de Farmácia. Laboratório de Pesquisas Clínicas. Ouro Preto, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Parasitologia. Laboratório de Toxoplasmose Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Grupo de Genômica e Biologia Computacional. Belo Horizonte, MG, Brasil.Universidade Federal de Ouro Preto. Escola de Farmácia. Laboratório de Pesquisas Clínicas. Ouro Preto, MG, Brasil.Universidade Federal de Ouro Preto. Escola de Farmácia. Laboratório de Pesquisas Clínicas. Ouro Preto, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Pesquisas Clínicas. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Parasitologia. Laboratório de Epidemiologia das Doenças Infecciosas e Parasitárias. Belo Horizonte, MG, Brasil/Universidade Federal de Minas Gerais. Faculdade de Medicina. Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical. Belo Horizonte, MG, Brasil.BACKGROUND: Certain municipalities in the Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil, have the highest human visceral leishmaniasis (VL) mortality rates in the country and also demonstrate high canine seropositivity. In Brazil, the etiologic agent of VL is Leishmania (Leishmania) infantum. The aim of this study was to evaluate the intraspecific genetic variability of parasites from humans and from dogs with different clinical forms of VL in five municipalities of BHMA using PCR-RFLP and two target genes: kinetoplast DNA (kDNA) and gp63. METHODS: In total, 45 samples of DNA extracted from clinical samples (n = 35) or L. infantum culture (n = 10) were evaluated. These samples originated from three groups: adults (with or without Leishmania/HIV co-infection; n = 14), children (n = 18) and dogs (n = 13). The samples were amplified for the kDNA target using the MC1 and MC2 primers (447 bp), while the Sg1 and Sg2 (1330 bp) primers were used for the gp63 glycoprotein target gene. RESULTS: The restriction enzyme patterns of all the samples tested were monomorphic. CONCLUSIONS: These findings reveal a high degree of genetic homogeneity for the evaluated gene targets among L. infantum samples isolated from different hosts and representing different clinical forms of VL in the municipalities of BHMA studied

Relationship of Leishmania-specific IgG levels and IgG avidity with parasite density and clinical signs in canine leishmaniasis.

The clinical status and tissue parasite burden of the skin and spleen of 40 dogs naturally infected with Leishmania chagasi (syn. Leishmania infantum), together with 5 uninfected control dogs, were assessed. On the basis of the clinical evaluation, infected dogs were classified as asymptomatic (AD) or symptomatic (SD). Infected animals were also grouped according to their parasite load as exhibiting low (LP), medium (MP) and high (HP) parasitism. The results indicated a high parasite load in the skin samples of SD animals in relation to the AD group. The serum immunoglobin isotype profiles of the studied animals revealed increased levels of IgG 1 in the AD and LP dogs, whereas high levels of IgG 2 were correlated with SD and HP dogs. The avidity index (AI) of IgG total in the SD group was high in comparison of that of the AD group. Moreover, animals with a larger parasite burden either in the spleen or skin showed higher AI values than animals with lower parasitism. Based on these findings, it is suggested that CVL commences with an asymptomatic clinical form with low parasitism, high production of IgG 1 and low affinity of IgG total molecules, and evolves into a symptomatic clinical form with higher parasitism intensity, higher IgG 2 levels, and high affinity of IgG tota

Relationship of Leishmania-specific IgG levels and IgG avidity with parasite density and clinical signs in canine leishmaniasis.

The clinical status and tissue parasite burden of the skin and spleen of 40 dogs naturally infected with Leishmania chagasi (syn. Leishmania infantum), together with 5 uninfected control dogs, were assessed. On the basis of the clinical evaluation, infected dogs were classified as asymptomatic (AD) or symptomatic (SD). Infected animals were also grouped according to their parasite load as exhibiting low (LP), medium (MP) and high (HP) parasitism. The results indicated a high parasite load in the skin samples of SD animals in relation to the AD group. The serum immunoglobin isotype profiles of the studied animals revealed increased levels of IgG 1 in the AD and LP dogs, whereas high levels of IgG 2 were correlated with SD and HP dogs. The avidity index (AI) of IgG total in the SD group was high in comparison of that of the AD group. Moreover, animals with a larger parasite burden either in the spleen or skin showed higher AI values than animals with lower parasitism. Based on these findings, it is suggested that CVL commences with an asymptomatic clinical form with low parasitism, high production of IgG 1 and low affinity of IgG total molecules, and evolves into a symptomatic clinical form with higher parasitism intensity, higher IgG 2 levels, and high affinity of IgG tota