Henri Dumon

Pediatric visceral leishmaniasis in southern France

PURPOSE The purposes of this study were to describe the characteristics of pediatric visceral leishmaniasis in southern France and to evaluate a new scheme of therapy. METHODS Hospital records of 59 children with visceral leishmaniasis were retrospectively reviewed. The period of the study was from 1981 to 1997. RESULTS All children but one lived or had previously dwelled in the south of France. None was coinfected with human immunodeficiency virus or known to be immunocompromised. The mean age was 31 months; 10 children were younger than 1 year when admitted to the hospital. The male:female ratio was 0.73. Fever and splenomegaly were present in 90 and 100%, respectively. Anemia, leukopenia and thrombocytopenia were commonly observed, especially in the youngest patients. Hypergammaglobulinemia was noted in 64%. A biopsy sample of the bone marrow was always performed, but direct microscopic examination failed to identify Leishmania in 13 (22%) cases. In these patients specific serology and genomic amplification with polymerase chain reaction were useful tools for the diagnosis. All patients were initially treated with meglumine antimonate (Glucantime). Twenty-six (44%) patients receiving the drug experienced at least one adverse event during treatment. Treatment failure occurred in six children (10%), who were subsequently cured with liposomal amphotericin B. Three additional children were treated with liposomal amphotericin B. All the children were finally cured and no death was observed. CONCLUSION Our experience suggests that liposomal amphotericin B is effective therapy for visceral leishmaniasis in children.

LDBio-Toxo II Immunoglobulin G Western Blot Confirmatory Test for Anti-Toxoplasma Antibody Detection

ABSTRACT Tests commonly used for routine determination of anti-Toxoplasma gondii immunoglobulin G (IgG) antibodies show a high level of consistency. However, considerable variations between commercial screening tests are still observed in detecting antibodies present at low concentrations, leading to a number of discrepant and/or equivocal results. It is therefore important to use a reference test to confirm borderline results. In this study, we evaluated the use of a new qualitative test based on Western blot analysis—the LDBio-Toxo II IgG test—as a confirmatory test for at-risk patients. The study was performed retrospectively, using 569 serum samples with “low-positive” (2 to 32 international units) anti-Toxoplasma IgG levels from 375 patients. These samples were either sera collected during the routine screening of pregnant women, from patients with unrelated infections, or from immunocompromised patients or sequential sera taken from pregnant women with acquired Toxoplasma infection or from their newborns during follow-up. The LDBio-Toxo II IgG test was compared to several commercial tests commonly used for anti-Toxoplasma IgG screening. The Sabin-Feldman dye test was used as a reference test. In this study, the results of the LDBio-Toxo II IgG test appeared to be consistent with those of the dye test; the LDBio-Toxo II IgG test had a specificity of 100% and a sensitivity of 99.2%. Our findings suggest that the LDBio-Toxo II IgG test is a useful serological tool in cases in which the presence or absence of Toxoplasma antibodies needs to be reliably determined, for example, for the follow-up of pregnant women and their newborns or for subjects with immune deficiencies following human immunodeficiency virus infection, hematological malignancies, or transplantation.

Comparison of PCR-ELISA and Real-Time PCR for invasive aspergillosis diagnosis in patients with hematological malignancies

This study aimed at comparing a real-time PCR assay and a PCR-ELISA assay of both serum and bronchoalveolar lavage (BAL) samples for the diagnosis of invasive aspergillosis (IA) in patients with hematological malignancies. Using a nested case-control design, 163 patients at risk were prospectively monitored and PCR assays were performed on frozen aliquots of 459 sera which were prospectively sampled twice weekly and 42 BAL specimens sampled from 43 probable and one proven IA cases and 47 matched controls. The data from three patients classified as possible IA were excluded from the nested case-control study. The sensitivity of real-time PCR and PCR-ELISA assays in serum was 73% and 86%, respectively and specificity was 100% for both. In BAL, sensitivity was 64% for real-time PCR, 71% for PCR-ELISA and 86% for Galactomannan antigen (GMA) assays with specificities of 96%, 96%, and 93%, respectively. While slightly less sensitive, the real time-PCR assay was highly specific and considerably faster and more workable than PCR-ELISA. Combining real-time PCR and GMA detection for both serum and BAL samples enhances routine laboratory IA diagnosis.

Choice of therapy for imported cases of falciparum malaria in children: a retrospective study of 100 cases seen in Marseilles, France

We have carried out a retrospective study on 100 children in hospital in Marseilles, France with a diagnosis of Plasmodium falciparum malaria. On admission, the main clinical features were anaemia (90 cases), fever (83 cases, > 40 degrees C in 22 cases), hepatomegaly (44 cases), vomiting (29 cases), neurological signs (22 cases), thrombocytopenia (13 cases), hyperparasitaemia (6 cases), jaundice (4 cases), shock (1 case) and hypoglycaemia (1 case). Severe malaria, as defined by the World Health Organization Malaria Action Programme, was rare in our study (only 2 cases) and the prognosis was good (no death, no sequela). The search for neurological signs such as impaired consciousness, prostration or convulsions is an effective and simple way to diagnose potentially severe cases. In the presence of these signs, intravenous quinine treatment resulted in a shortened duration of fever (30 h instead of 63 h) and thereby avoided patients becoming worse. In children without neurological signs or persistent vomiting, oral therapy may be used even if there is high fever or hyperparasitaemia, but close surveillance is required. Patients treated with halofantrine or mefloquine had a shorter stay in hospital than those treated with chloroquine (mean = 4 d instead of 5.7 d). The resistance of some strains to chloroquine may explain this difference.

Timely Diagnosis of Disseminated Toxoplasmosis by Sputum Examination

ABSTRACT The diagnosis of disseminated toxoplasmosis in a 14-year-old allogeneic bone marrow recipient with graft-versus-host disease was determined by the detection of Toxoplasma gondii tachyzoites in sputum smears. Sputum analysis is a valuable alternative in the clinical assessment of pulmonary toxoplasmosis, especially when conventional invasive techniques are not practicable.

Experimental schistosomiasis, protective aspects of granulomatous reaction in the mouse liver

We show two mechanisms of liver protection by the granulomatous reaction against Schistosoma mansoni eggs entrapped in the organ. First, eosinophil peroxidase and its substrate H2O2 are released by inflammatory cells in the immediate vicinity of the parasite eggs. The efficiency of this process was demonstrated by administration of antioxidants to infected mice. The treatment, which reduces H2O2 production, significantly improved the ability of parasite eggs to hatch after collection from the liver. Secondly, we labeled the released egg antigens in liver histological sections and we found that the lattice of collagen fibers which is built around eggs appears to create a barrier preventing released compounds from diffusing freely in surrounding tissues. Together, oxidative processes and antigen containment allow the parasitized liver to cope with the dual threat posed by parasite eggs, i.e. a highly resistant chitinous eggshell and the release of toxic substances.

Immunoblot Profile as Predictor of Toxoplasmic Encephalitis in Patients Infected with Human Immunodeficiency Virus

ABSTRACT In order to define more accurately human immunodeficiency virus-infected patients at risk of developing toxoplasmic encephalitis (TE), we assessed the prognostic significance of the anti-Toxoplasma gondii immunoglobulin G (IgG) immunoblot profile, in addition to AIDS stage, a CD4+ cell count <50/mm3, and an antibody titer ≥150 IU/ml, in patients with CD4 cell counts <200/mm3 and seropositive forT. gondii. Baseline serum samples from 152 patients included in the placebo arm of the ANRS 005-ACTG 154 trial (pyrimethamine versus placebo) were used. The IgG immunoblot profile was determined using a Toxoplasma lysate and read using the Kodak Digital Science 1D image analysis software. Mean follow-up was 15.1 months, and the 1-year incidence of TE was 15.9%. The cumulative probability of TE varied according to the type and number of anti-T. gondii IgG bands and reached 65% at 12 months for patients with IgG bands of 25 and 22 kDa. In a Cox model adjusted for age, gender, Centers for Disease Control and Prevention (CDC) clinical stage, and CD4 and CD8 cell counts, the incidence of TE was higher when the IgG 22-kDa band (hazard ratio [HR] = 5.4;P < 0.001), the IgG 25-kDa band (HR = 4.7;P < 0.001), or the IgG 69-kDa band (HR = 3.4;P < 0.001) was present and was higher for patients at CDC stage C (HR = 4.9; P < 0.001).T. gondii antibody titer and CD4 cell count were not predictive of TE. Thus, detection of IgG bands of 25, 22, and/or 69 kDa may be helpful for deciding when primary prophylaxis for TE should be started or discontinued, especially in the era of highly active antiretroviral therapy.

Specific anti-Toxoplasmic IgG antibody immunoblot profiles in patients with AIDS-associated Toxoplasma encephalitis

Among 186 suspected cases of Toxoplasma encephalitis (TE) in HIV-infected patients, 113 were classified as TE and 73 as non-TE. Serum Toxoplasma gondii (T.g.) antibodies were detected by ELISA in 97% of TE vs 71% of non-TE cases (p < 0.001). In the 164 patients positive for T. g. antibodies, the IgG 27 and 32 bands were more frequently present in TE than in non-TE (p = 0.003, p = 0.002, respectively). Among patients with positive T.g. serology, multivariate analysis showed that the presence of an IgG 32 (OR 3.1) or IgG 27 band (OR 2.7) on Western blot was highly indicative of TE independently of each other. Positive T.g. serology, but not anti-T.g. IgG antibody titres, was predictive. Thus, the positivity of IgG 27 and 32 bands on Western blot analysis provides useful data for improving the diagnosis of presumptive TE in HIV-infected patients with suspected TE and positive Toxoplasma serology.

Infection of mice by a Toxoplasma gondii isolate from an AIDS patient: virulence and activation of hosts' immune responses are independent of parasite genotype.

Virulence of a Toxoplasma gondii isolate from an AIDS patient (designated as PTN) was compared with that of PLK, a variant of P‐strain. Virulence was assessed in term of host survival upon inoculation in different strains of mice. All C57BL/6 mice died of acute toxoplasmosis by 7–10 days following intraperitoneal infection with 1 × 105 tachyzoites of PTN and 40% of BALB/c died on day 23 of infection, whereas 100% CBA/J infected with the same dose of PTN survived, as did outbred Swiss Webster mice. All C57BL/6, BALB/c, CBA/J, or Swiss Webster died of acute toxoplasmosis by 3–9 days postinfection upon inoculation with same dose of tachyzoites of the PLK strain. Further studies in CBA/J mice demonstrated that mice infected with PTN elicited a significantly higher lymphoproliferative response to crosslinked anti‐CD3 mAb or Con A than PLK infected mice, and augmented production of TNFα, lower levels of nitrite and a higher number of NK cells. Genetical analysis indicated that both PLK and PTN strains of T. gondii are from type ll. Interestingly, being of the same genotype, the later showed less virulence upon inoculation in mice and had greater capacity to activate host immune system than the PLK strain.

Late post-operative Aspergillus flavus endocarditis: Demonstration of a six years incubation period using microsatellite typing.

Late post-operative Aspergillus endocarditis is an under recognized life-threatening complication of heart valvular surgery. Optimal prevention and treatment need enhanced awareness. We report three cases of post-operative Aspergillus flavus endocarditis, including one with a 6-year long incubation period. Microsatellite typing incriminated a recurrent contamination of hospital environment.