Molecular epidemiology of cutaneous leishmaniasis and heterogeneity of Leishmania major strains in Iran.

OBJECTIVE: To determine the geographical distribution of Leishmania species causing cutaneous leishmaniasis (CL) and to study the genetic heterogeneity of Leishmania major isolates from different endemic areas of Iran. METHODS: A total of 341 isolates from lesions of patients living in 11 provinces of Iran were grown in culture medium and inoculated to BALB/c mice to detect possible visceralisation. The species were identified by isoenzyme analysis using a battery of six enzymes and kinetoplast (k) DNA-PCR technique. Genetic variation among L. major isolates was analysed by random amplified polymorphic DNA (RAPD) technique. RESULTS: Of the total 341 isolates, 283 isolates were L. major and 58 isolates were Leishmania tropica. In rural areas, the causative agent of CL was mainly L. major (95%L. major vs. 5%L. tropica), in urban areas it was L. tropica (65%L. tropica vs. 35%L. major). All isolates of L. major and 8.6% of L. tropica isolates showed visceralisation in BALB/c mice. There is considerable genetic diversity between L. major strains from different endemic areas and even between some isolates of the same endemic area. CONCLUSION: Leishmania major is the most frequent species in the endemic areas of CL in eleven provinces of Iran, and genetic diversity is a common feature of L. major in the country.

Assessment of interferon-γ levels and leishmanin skin test results in persons recovered for leishmaniasis.

Patients who recover from leishmaniasis usually show development of strong immunity and induction of interferon-γ (IFN-γ) and delayed type hypersensitivity. In a randomized trial, we analyzed the IFN-γ response by using a Quantiferon-Leishmania assay against three Leishmania peptide antigens and compared it with results of the leishmanin skin test (LST) in persons residing in areas in Iran to which zoonotic cutaneous leishmaniasis (ZCL, 181 persons), anthroponotic cutaneous leishmaniasis (ACL, 104 persons), and zoonotic visceral leishmaniasis (ZVL, 67 persons) are endemic. The percentage of persons with an IFN-γ-positive response (> 0.2 IU/mL) to three antigens and the mean concentration of IFN-γ induced by the antigens were higher for persons from areas endemic for ZVL than for persons from areas endemic for ZCL and ACL. The percentage of persons with LST-positive results (≥ 5 mm indurations) was 99%, 94%, and 70% for areas with ZCL, ACL, and ZVL, respectively. Our data indicate that the LST is significantly more sensitive than IFN-γ levels in persons who have been cured of cutaneous leishmaniasis than in persons who have been cured of ZVL.

Mechanisms controlling anaemia in Trypanosoma congolense infected mice.

BACKGROUND: Trypanosoma congolense are extracellular protozoan parasites of the blood stream of artiodactyls and are one of the main constraints on cattle production in Africa. In cattle, anaemia is the key feature of disease and persists after parasitaemia has declined to low or undetectable levels, but treatment to clear the parasites usually resolves the anaemia. METHODOLOGY/PRINCIPAL FINDINGS: The progress of anaemia after Trypanosoma congolense infection was followed in three mouse strains. Anaemia developed rapidly in all three strains until the peak of the first wave of parasitaemia. This was followed by a second phase, characterized by slower progress to severe anaemia in C57BL/6, by slow recovery in surviving A/J and a rapid recovery in BALB/c. There was no association between parasitaemia and severity of anaemia. Furthermore, functional T lymphocytes are not required for the induction of anaemia, since suppression of T cell activity with Cyclosporin A had neither an effect on the course of infection nor on anaemia. Expression of genes involved in erythropoiesis and iron metabolism was followed in spleen, liver and kidney tissues in the three strains of mice using microarrays. There was no evidence for a response to erythropoietin, consistent with anaemia of chronic disease, which is erythropoietin insensitive. However, the expression of transcription factors and genes involved in erythropoiesis and haemolysis did correlate with the expression of the inflammatory cytokines Il6 and Ifng. CONCLUSIONS/SIGNIFICANCE: The innate immune response appears to be the major contributor to the inflammation associated with anaemia since suppression of T cells with CsA had no observable effect. Several transcription factors regulating haematopoiesis, Tal1, Gata1, Zfpm1 and Klf1 were expressed at consistently lower levels in C57BL/6 mice suggesting that these mice have a lower haematopoietic capacity and therefore less ability to recover from haemolysis induced anaemia after infection.

Expansion of gammadelta T Cells in patients infected with cutaneous leishmaniasis with and without glucantime therapy.

The expansion of gammadelta T cells in patients with active cutaneous leishmaniasis, with or without glucantime therapy, was investigated. Twenty patients with local cutaneous leishmaniasis including glucantime-treated (n=10) and untreated (n=10) patients were selected. The controls were healthy individuals (n=10) living in endemic areas. Whole blood was obtained and the T cell subpopulations were analyzed by flow cytometry. Significantly more gammadelta CD(3)(+) T cells were observed in untreated patients (15.9% +/-5.9), when compared with glucantime-treated patients (4.6% +/-1.4) and controls (5.3% +/-2.3). On the other hand, when the percentages of alphabeta CD(3)(+) T-cells were analyzed different results were obtained. A significant increase in alphabeta T cells was seen in glucantime-treated patients (62.4% +/-7.6), when compared to the untreated patients (55.7% +/-5.5) and controls (55.1% +/-9.6). The percentage of total CD(3)(+) T cells was statistically greater in both glucantime-treated (68.8% +/-7.4) and untreated patients (73.4% +/-5.9) when compared to the controls (61% +/-10.3). These results are consistent with previous results on the expansion of gammadelta T cells during the course of cutaneous leishmaniasis. They also indicate that glucantime therapy can reverse the expansion of gammadelta T cells and as a result increase the percentages of alphabeta ab CD(3)(+) T cells.

Expansion of gammadelta T cells in patients infected with cutaneous leishmaniasis with and without glucantime therapy

The expansion of gammadelta T cells in patients with active cutaneous leishmaniasis, with or without glucantime therapy, was investigated. Twenty patients with local cutaneous leishmaniasis including glucantime-treated (n=10) and untreated (n=10) patients were selected. The controls were healthy individuals (n=10) living in endemic areas. Whole blood was obtained and the T cell subpopulations were analyzed by flow cytometry. Significantly more gammadelta CD(3)(+) T cells were observed in untreated patients (15.9% +/-5.9), when compared with glucantime-treated patients (4.6% +/-1.4) and controls (5.3% +/-2.3). On the other hand, when the percentages of alphabeta CD(3)(+) T-cells were analyzed different results were obtained. A significant increase in alphabeta T cells was seen in glucantime-treated patients (62.4% +/-7.6), when compared to the untreated patients (55.7% +/-5.5) and controls (55.1% +/-9.6). The percentage of total CD(3)(+) T cells was statistically greater in both glucantime-treated (68.8% +/-7.4) and untreated patients (73.4% +/-5.9) when compared to the controls (61% +/-10.3). These results are consistent with previous results on the expansion of gammadelta T cells during the course of cutaneous leishmaniasis. They also indicate that glucantime therapy can reverse the expansion of gammadelta T cells and as a result increase the percentages of alphabeta ab CD(3)(+) T cells