The C-terminal segment of Leishmania major HslU: Toward potential inhibitors of LmHslVU activity.

It is urgent to develop less toxic and more efficient treatments for leishmaniases and trypanosomiases. We explore the possibility to target the parasite mitochondrial HslVU protease, which is essential for growth and has no analogue in the human host. For this, we develop compounds potentially inhibiting the complex assembly by mimicking the C-terminal (C-ter) segment of the ATPase HslU. We previously showed that a dodecapeptide derived from Leishmania major HslU C-ter segment (LmC12-U2, Cpd 1) was able to bind to and activate the digestion of a fluorogenic substrate by LmHslV. Here, we present the study of its structure-activity relationships. By replacing each essential residue with related non-proteinogenic residues, we obtained more potent analogues. In particular, a cyclohexylglycine residue at position 11 (cpd 24) allowed a more than three-fold gain in potency while reducing the size of compound 24 from twelve to six residues (cpd 50) without significant loss of potency, opening the way toward short HslU C-ter peptidomimetics as potential inhibitors of HslV proteolytic function. Finally, conjugates constituted of LmC6-U2 analogues and a mitochondrial penetrating peptide were found to penetrate into the promastigote form of L. infantum and to inhibit the parasite growth without showing toxicity toward human THP-1 cells at the same concentration (i.e. 30 µM).

Characteristics and outcome according to underlying disease in non-AIDS patients with acute respiratory failure due to Pneumocystis pneumonia.

In the non-AIDS group, several underlying conditions and immune defects could lead to different PCP presentations. This study compared PCP presentation and outcome according to the underlying disease. A secondary analysis of a previously published prospective observational study including 544 PCP patients was done. Only non-AIDS patients were included. Underlying disease was defined as chronic lymphocytic leukemia (CLL), organ transplantation, solid cancer, allogeneic hematopoietic stem cell transplant (AHSCT), other hematological diseases, and immunosuppressive treatment. Clinical characteristics and outcomes were compared between groups. Multiple correspondent analyses compared clinical characteristics at diagnosis. Day 30 mortality was analyzed. Three hundred and twenty-one patients were included in the study. The underlying diseases were hematological malignancy (n = 75), AHSCT (n = 14), CLL (n = 19), solid organ transplant (n = 94), solid tumor (n = 39), and immunosuppressive treatment (n = 57). Compared with other underlying diseases, PCP related to CLL was closer to PCP related to AIDS presentation (long duration of symptoms before diagnosis, high level of dyspnea, and low oxygen saturation at diagnosis). Day 30 mortality was associated with underlying disease, oxygen flow, and shock at ICU admission. PCP presentations may vary according to the underlying reason for immunosuppression. Response to treatment and adjuvant steroid therapy should be analyzed regarding this result.

A case of congenital toxoplasmosis-associated miscarriage with maternal infection four months prior to conception.

BACKGROUND: We report a case of fatal congenital toxoplasmosis with maternal infection dated four months before pregnancy in the absence of any specific immunosuppressive condition. CASE: Ms. D. experienced submaxillary lymphadenitis in February 2018. The medical workup performed revealed an acute T. gondii infection. She became pregnant in June 2018 while she still had adenopathy. The second obstetrical ultrasound, performed at 16 weeks of pregnancy, revealed a fetal death. The research for T. gondii by PCR was positive in the products of conception. CONCLUSION: Diagnosis of toxoplasmosis should be discussed in case of miscarriage with lymphadenitis. As lymph nodes in T. gondii infection could be responsible for iterative release of parasites and fetal death, symptomatic toxoplasmosis should be treated in women of childbearing age.

Evaluation of six commercial kits for the serological diagnosis of Mediterranean visceral leishmaniasis.

BACKGROUND: Zoonotic visceral leishmaniasis (VL) is endemic in the Mediterranean basin. However, large-scale comparative analyses of the commercial kits for the serological diagnosis of this neglected disease are lacking. This study compared the performances of four enzyme-linked immunosorbent assays (ELISA) and two immunochromatographic tests (ICT) as screening tests for the serodiagnosis of human VL in the Mediterranean region. METHODOLOGY/PRINCIPAL FINDINGS: Serum samples from 319 patients living in France, Tunisia or Morocco were tested using two ICT (IT LEISH and TruQuick LEISH IgG/IgM Meridian) and four ELISA reagents (NovaLisa Leishmania infantum IgG, Bordier Leishmania infantum, Ridascreen Leishmania IgG, and Vircell Leishmania). The population with proven VL (n = 181) included 65 immunocompromised patients. Significantly higher percentages of false-negative results were obtained with all assays in immunocompromised patients, compared with the immunocompetent population. In the whole population, sensitivity and specificity ranged from 80.7% to 93.9% and from 95.7% to 100%, respectively. The maximum accuracy was observed with the Bordier and Vircell ELISA kits (96.2%), and the lowest accuracy with Ridascreen reagent (88.7%). New thresholds of positivity are proposed for the Bordier, Vircell and NovaLisa ELISA kits to achieve 95% sensitivity with the highest possible specificity. Western blot (WB), used as a confirmation method, showed 100% sensitivity and identified 10.1% of asymptomatic carriers among the control population from the South of France. CONCLUSIONS/SIGNIFICANCE: This is the first study that compared commercially available kits for VL serodiagnosis in the endemic region of the Mediterranean basin. It provides specific information about the tests' performance to help clinicians and biologists to select the right assay for VL screening.

Leishmania infection: Misdiagnosis as cancer and tumor-promoting potential.

Given the prevalence of cancer and leishmaniasis worldwide, the presence of these two pathologies in the same tissue sample may be merely fortuitous. The clinical outcome of both diseases is under the control of innate and adaptive immunity, and in both cases these progressive diseases are characterized by an impaired host Th1 response. As a consequence, the Th2 cytokine microenvironment occurring in progressive leishmaniasis may potentially promote tumor cell proliferation and vice versa. On the other hand, clinical aspects of subclinical cutaneous or visceral leishmaniasis sometimes closely resemble those observed in various neoplasms thus leading to misdiagnosis. In this review, we present recent findings on the association between leishmaniasis and malignant disorders. Our review includes HIV positive, HIV negative subjects and patients whose HIV status has not been established. Leishmaniasis mimicking a malignant disorder was confirmed and extended to unreported neoplastic disorders including squamous cell carcinoma, T-cell and B-cell lymphoma, oral and intranasal tumors and granulomas. Thus, leishmaniasis should be considered in the differential diagnosis and course of various cancers in Leishmania endemic areas or in patients with travel history to these areas. We also listed recent reports showing that Leishmania can promote cancer development in immunocompromised as well as in immunocompetent patients. The potential mechanisms supporting this promoting effect are discussed.

Management of toxoplasmosis in transplant recipients: an update.

INTRODUCTION: Toxoplasmosis is a life-threatening parasitic disease for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. The risk of toxoplasmosis in transplant patients mainly depends on the degree of immunosuppression, the tropism of Toxoplasma gondii for the grafted tissue, and the seroprevalence in the general population. Although transplant recipients with toxoplasmosis have a high mortality rate, there are neither well-defined recommendations nor a consensus for the management of this disease in these patients. Areas covered. This review focuses on the management of toxoplasmosis in transplant recipients and discusses the various strategies for diagnosis, prevention, treatment, and follow-up in clinical practice. The literature search was conducted on publications in English and French using the search terms 'Toxoplasma gondii,' 'organ transplant,' and 'transplant recipients.' Expert commentary. The diagnosis of toxoplasmosis has greatly improved over the last two decades, but it is still a fatal illness. Non-specificity of the symptoms, resulting in a delay before diagnosis, and therapeutic failure are the main causes of death. The development of active treatments against cysts is one of the current challenges that will considerably improve the management of toxoplasmosis in transplant recipients by clearing chronic infection to avoid T. gondii reactivation.

Multiplexed Anti-Toxoplasma IgG, IgM, and IgA Assay on Plasmonic Gold Chips: towards Making Mass Screening Possible with Dye Test Precision.

Toxoplasmosis is an infection caused by the protozoan parasite Toxoplasma gondii that can lead to severe sequelae in the fetus during pregnancy. Definitive serologic diagnosis of the infection during gestation is made mostly by detecting T. gondii-specific antibodies, including IgG and IgM, individually in a single serum sample by using commercially available kits. The IgA test is used by some laboratories as an additional marker of acute infection. Most of the commercial tests have failed to reach 100% correlation with the reference method, the Sabin-Feldman dye test for the detection of Toxoplasma IgG antibodies. For Toxoplasma IgM and IgA antibodies, there is no reference method and their evaluation is done by comparing the results of one assay to those of another. There is a need for multiplexed assay platforms, as the serological diagnosis of T. gondii infection does not rely on the detection of a single Ig subtype. Here we describe the development of a plasmonic gold chip with vast fluorescence enhancement in the near-infrared region for simultaneous detection of IgG, IgM, and IgA antibodies against T. gondii in an ∼1-µl serum or whole-blood sample. When 168 samples were tested on this platform, IgG antibody detection sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were all 100%. IgM antibody detection achieved 97.6% sensitivity and 96.9% specificity with a 90.9% PPV and a 99.2% NPV. Thus, the nanoscience-based plasmonic gold platform enables a high-performance, low-cost, multiplexed assay requiring ultrasmall blood volumes, paving the way for the implementation of universal screening for toxoplasmosis infection during gestation.

Hepatopulmonary syndrome associated with visceral leishmaniasis.

Leishmaniasis caused by Leishmania infantum is endemic in the Mediterranean region. Its visceral form can present a diagnostic challenge owing to the disease's wide spectrum of clinical presentations. We describe the very atypical case of a 66-year-old male Caucasian patient with hepatopulmonary syndrome and an exceptionally rare expression of visceral leishmaniasis in a disseminated form with mucocutaneous involvement presenting as an autoimmune systemic disease.

Visceral leishmaniasis due to Leishmania infantum with renal involvement in HIV-infected patients.

BACKGROUND: We describe histological, clinical findings and outcomes of renal involvement during Leishmania infantum infection in four HIV-infected patients in South France and North Italy hospital settings. CASES PRESENTATION: Four HIV-infected Caucasian patients (age 24-49) performed renal biopsy during episodes of visceral leishmaniasis. They presented severe immunosuppression, frequent relapses of visceral leishmaniasis during a follow-up period of several years and partial or complete recovery of renal function after anti-parasitic treatment. Main clinical presentations were nephrotic or nephritic syndrome and/or acute renal failure secondary to membranoproliferative type III glomerulonephritis or acute interstitial nephritis. Clinical outcome was poor, probably as a consequence of insufficient immuno-virological control of the HIV infection. CONCLUSIONS: Our findings suggest that the main histological findings in case of renal involvement due to Leishmania infantum infection in HIV-infected patients are type III MPGN and acute interstitial nephritis, with a histological specificity similar to that observed in canine leishmaniasis. Poor immune status in HIV-infected patients, altering the capacity for parasite clearance, and prolonged course of chronic active VL in this population may lead to the development of specific renal lesions.

Mucosal Leishmania infantum leishmaniasis: specific pattern in a multicentre survey and historical cases.

OBJECTIVE: Leishmania infantum mucosally restricted leishmaniasis was rarely reported, so that diagnostic and treatment strategies remain debated. A long-term multicentric survey appeared thereby necessary. METHODS: Cases were prospectively collected over 12 years in 3 academic hospitals of Southern France. Predisposing factors, clinical findings, diagnostic procedures, treatment and outcome were compared to medical literature. RESULTS: Ten new cases and 40 historical reports were collected. Respectively 10/10 and 35/40 patients were adult males. Immunodeficiency was frequent (5/10 and 18/40). No previous cutaneous lesion was reported. Leishmaniasis affected mostly larynx (5/10 and 19/40), but also mouth (2/10 and 19/40) and nose (3/10 and 5/40). Lesions were highly polymorph. Mucosa histological examination provided respectively 1/10 and 2/40 false negative results, contrary to serum immunoblotting and PCR on mucosal biopsy. Although local response was always satisfactory even using topical treatment, subsequent visceral spreading was observed in 2/10 and 1/40 cases. CONCLUSION: L. infantum mucosally restricted leishmaniasis exhibits a specific pattern, marked by tropism for adult males, high clinical and histological polymorphism. Immunoblot screening and PCR confirmation of suspected lesions are necessary because of direct examination occasional false negative results. The risk of visceral spreading sustains systemic therapy. SUMMARY: Leishmania infantum mucosal leishmaniasis mostly affects adult males, half of them immunodeficient. Clinical and histological polymorphism makes the diagnosis difficult, stressing the need for immunoblot screening and mucosa PCR analysis of suspected cases. Possible visceralization sustains systemic therapy.