title: Leishmania (Viannia) guyanensis induces low immunologic responsiveness in leishmaniasis patients from an endemic area of the Brazilian Amazon Highland.
abstract: Cutaneous leishmaniasis caused by Leishmania (Viannia) guyanensis (CL-Lguy) is endemic in the Brazilian Amazon, differing from L. braziliensis infection in clinical, diagnostic, and therapeutic aspects. T-cell reactivity to leishmanial antigens possibly involved in the pathogenesis of CL-Lguy was studied herein. Variable lymphoproliferative responses (LPRs) to Leishmania antigens were found among the 23 studied patients, and 50% of them showed low or no response to these antigens. Active disease was associated with an enrichment of leishmanial-reactive T lymphocytes, mainly TCD4(+). High and low interferon (IFN)-gamma producers were observed. TNF-alpha, interleukin (IL)-10, and IL-5 were consistently detected. CL-Lguy displayed low antibody response in comparison to L. braziliensis patients. CL caused by L. braziliensis presented positive LPRs and higher IFN-gamma production but undetectable IL-5. L. guyanensis seems to induce a down-regulation of the immune system compared with L. braziliensis. This finding could explain some aspects of clinical presentation of CL-Lguy, such as high tissue parasite burden and frequent resistance to therapy.
authors.affiliation: Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil.
authors.forename: Nubia Estela
authors.initials: NE
authors.lastname: Matta
authors.forename: Ricardo S
authors.initials: RS
authors.lastname: Nogueira
authors.forename: Antonia Maria Ramos
authors.initials: AM
authors.lastname: Franco
authors.forename: Ilner
authors.initials: I
authors.lastname: de Souza E Souza
authors.forename: Marise S
authors.initials: MS
authors.lastname: Mattos
authors.forename: Manoel P
authors.initials: MP
authors.lastname: Oliveira-Neto
authors.forename: Sergio G
authors.initials: SG
authors.lastname: Coutinho
authors.forename: Leonor L
authors.initials: LL
authors.lastname: Leon
authors.forename: Alda Maria
authors.initials: AM
authors.lastname: Da-Cruz
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D016207:Cytokines / Q000096:biosynthesis* / Q000097:blood; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D018334:Leishmania guyanensis / Q000276:immunology*; D007897:Leishmaniasis, Mucocutaneous / Q000453:epidemiology / Q000276:immunology* / Q000469:parasitology; D016131:Lymphocyte Subsets / Q000276:immunology*; D008297:Male; D055815:Young Adult
chemical_list: D000913:Antibodies, Protozoan; D016207:Cytokines