Intralesional regulatory T-cell suppressive function during human acute and chronic cutaneous leishmaniasis due to Leishmania guyanensis.

The levels of regulatory T cells (Treg cells), analyzed by Foxp3 mRNA expression, were determined in lesions from patients with acute cutaneous leishmaniasis (ACL) and chronic cutaneous leishmaniasis (CCL). We demonstrated that Treg cells preferentially accumulate in lesions from ACL patients during the early phase of infection (lesion duration of less than 1 month). In addition, levels of Foxp3 mRNA transcripts were significantly higher in specimens from patients with CCL than in those from patients with ACL, suggesting a critical role of intralesional Treg cells in CCL. Intralesional Treg cells from both ACL and CCL patients were shown to have suppressive functions in vitro, since they inhibited the gamma interferon (IFN-gamma) produced by CD4(+) CD25(-) T cells purified from peripheral blood mononuclear cells from the same patient in response to Leishmania guyanensis stimulation. Intralesional 2,3-indoleamine dioxygenase (IDO) mRNA expression was associated with that of Foxp3, suggesting a role for IDO in the suppressive activity of intralesional Treg cells. In addition, a role, albeit minor, of interleukin-10 (IL-10) was also demonstrated, since neutralization of IL-10 produced by intralesional T cells increased IFN-gamma production by effector cells in an in vitro suppressive assay. These results confirm the role of intralesional Treg cells in the immunopathogenesis of human Leishmania infection, particularly in CCL patients.

[Overview of endemic treponematoses]. / Panorama des tréponématoses endémiques.

Endemic treponematoses including yaws, bejel, pinta are distinguished from venereal syphilis on the basis of epidemiological characteristics and clinical manifestations. They cannot be differentiated by morphological and serological methods. A few minor genetic differences have been identified among the subspecies (Treponema pallidum sp. pallidum, pertenue, endemicum, carateum). Although penicillin therapy is effective, these infectious diseases have yet to be eliminated.

[Cutaneous neonatal lupus erythematosus: discordant expression in identical twins]. / Lupus erythémateux néonatal cutané: expression discordante chez des jumelles monozygotes.

BACKGROUND: Neonatal lupus erythematosus is a rare syndrome characterized essentially by cutaneous lesions and/or congenital heart block occurring in infants at birth, or shortly after. It is related to transplacental crossing of maternal auto antibodies (usually anti Ro/SS-A, La/SS-B or rarely anti-U(1) RNP) from the mother to the infant. Mothers of affected children have signs of systemic lupus erythematosus or other collagenosis or are asymptomatic. CASE REPORT: We report a case of neonatal lupus erythematosus in one identical twin, revealed at the age of 3 months by erythematous and annular cutaneous lesions of the face and limbs. These lesions were preceded at birth by an asymmetrical livedo pattern of the lower limbs. Her twin sister was unaffected but both infants had a high rate of anti-Ro/SSA antibodies. The diagnosis of neonatal lupus erythematosus permitted to reveal a biological lupus syndrome in their asymptomatic mother. Cutaneous lesions cleared almost completely within 1 year whereas antiRo/SSA antibodies disappeared. CONCLUSION: Cases of neonatal lupus erythematosus in twins are rare and mostly described in heterozygotic twins. Clinical discordance is usual and could partly be explained by genetic factors. In monozygotic twins, like in our case, chromosome X inactivation could be an explanation of the differences observed.

High circulating proviral load with oligoclonal expansion of HTLV-1 bearing T cells in HTLV-1 carriers with strongyloidiasis.

Adult T cell leukemia (ATLL) develops in 3 - 5% of HTLV-1 carriers after a long period of latency during which a persistent polyclonal expansion of HTLV-1 infected lymphocytes is observed in all individuals. This incubation period is significantly shortened in HTLV-1 carrier with Strongyloides stercoralis (Ss) infection, suggesting that Ss could be a cofactor of ATLL. As an increased T cell proliferation at the asymptomatic stage of HTLV-1 infection could increase the risk of malignant transformation, the effect of Ss infection on infected T lymphocytes was assessed in vivo in HTLV-1 asymptomatic carriers. After real-time quantitative PCR, the mean circulating HTLV-1 proviral load was more than five times higher in HTLV-1 carriers with strongyloidiasis than in HTLV-1+ individuals without Ss infection (P<0.009). This increased proviral load was found to result from the extensive proliferation of a restricted number of infected clones, i.e. from oligoclonal expansion, as evidenced by the semiquantitative amplification of HTLV-1 flanking sequences. The positive effect of Ss on clonal expansion was reversible under effective treatment of strongyloidiasis in one patient with parasitological cure whereas no significant modification of the HTLV-1 replication pattern was observed in an additional case with strongyloidiasis treatment failure. Therefore, Ss stimulates the oligoclonal proliferation of HTLV-1 infected cells in HTLV-1 asymptomatic carriers in vivo. This is thought to account for the shortened period of latency observed in ATLL patients with strongyloidiasis. Oncogene (2000) 19, 4954 - 4960

[Histoplasmosis due to Histoplasma capsulatum capsulatum and HIV infection]. / Histoplasmose à Histoplasma capsulatum capsulatum et infection à VIH.

PURPOSE: Histoplasmosis due to Histoplasma capsulatum is a granulomatous fungic infection which appears opportunistic and disseminated in immunocompromised patients, especially among HIV patients in whom it can lead to death. Histoplasmosis is endemic in numerous areas worldwide, but in Europe most of the cases reported are imported. We describe the clinical features and the available diagnosis methods issued from our experience in French Guyana. METHODS: Contamination occurs by inhalation of spores contained in dust. Most endemic areas are located on the American continent, including the French West Indies, where the incidence of histoplasmosis among HIV patients in French Guyana varies from 1.2 to 2.2% per year. In non-immunocompromised patients, histoplasmosis is asymptomatic most of the time. In HIV patients, the disseminated form is common and may occur many years after exposure to the fungus. RESULTS: Non-specific symptoms, similar to those of either tuberculosis or other opportunistic infections, may reveal disseminated histoplasmosis in patients with AIDS. Early treatment (amphotericin B or itraconazole) is effective; however, it should be followed by a lifelong antifungic treatment (itraconazole) to prevent relapse. CONCLUSION: The infection should be suspected in any febrile HIV-infected patient with CD4 blood cell count < 200/mm3, if he/she ever travelled in an endemic zone. Direct examination of smear relating to clinical symptoms help guide diagnosis, while culture will confirm it after at least 4 weeks. Efficient serologic techniques for HIV-infected patients are not available in Europe.