Henry W. Murray

Advances in leishmaniasis

Governed by parasite and host factors and immunoinflammatory responses, the clinical spectrum of leishmaniasis encompasses subclinical (inapparent), localised (skin lesions), and disseminated infection (cutaneous, mucosal, or visceral). Symptomatic disease is subacute or chronic and diverse in presentation and outcome. Clinical characteristics vary further by endemic region. Despite T-cell-dependent immune responses, which produce asymptomatic and self-healing infection, or appropriate treatment, intracellular infection is probably life-long since targeted cells (tissue macrophages) allow residual parasites to persist. There is an epidemic of cutaneous leishmaniasis in Afghanistan and Pakistan and of visceral infection in India and Sudan. Diagnosis relies on visualising parasites in tissue or serology; culture and detection of parasite DNA are useful in the laboratory. Pentavalent antimony is the conventional treatment; however, resistance of visceral infection in India has spawned new treatment approaches--amphotericin B and its lipid formulations, injectable paromomycin, and oral miltefosine. Despite tangible advances in diagnosis, treatment, and basic scientific research, leishmaniasis is embedded in poverty and neglected. Current obstacles to realistic prevention and proper management include inadequate vector (sandfly) control, no vaccine, and insufficient access to or impetus for developing affordable new drugs.

Pneumocystis carinii Pneumonia: A Comparison Between Patients with the Acquired Immunodeficiency Syndrome and Patients with Other Immunodeficiencies

Clinical features of 49 episodes of Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome were compared with those of 39 episodes in patients with other immunosuppressive diseases. At presentation patients with the syndrome were found to have a longer median duration of symptoms (28 days versus 5 days, p = 0.0001), lower mean respiratory rate (23.4 versus 30, p = 0.005), and higher median room air arterial oxygen tension (69 mm Hg versus 52 mm Hg, p = 0.0002). The survival rate from 1979 to 1983 was similar for the two groups (57% and 50% respectively). Patients with the syndrome had a higher incidence of adverse reactions to trimethoprim-sulfamethoxazole (22 of 34 versus 2 of 17, p = 0.0007). Survivors with the syndrome at initial presentation had a significantly lower respiratory rate, and higher room air arterial oxygen tension, lymphocyte count, and serum albumin level compared to nonsurvivors. Pneumocystis carinii pneumonia presents as a more insidious disease process in patients with the syndrome, and drug therapy in these patients is complicated by frequent adverse reactions.

Failure of pentavalent antimony in visceral leishmaniasis in India : Report from the center of the Indian Epidemic

In India, 320 patients with visceral leishmaniasis (209 in the state of Bihar and 11 in the neighboring state of Uttar Pradesh) received identical pentavalent antimony (Sb) treatment. Sb induced long-term cure in 35% (95% confidence interval [CI], 28%-42%) of those in Bihar versus 86% (95% CI, 79%-93%) of those in Uttar Pradesh. In Bihar, the center of the Indian epidemic, traditional Sb treatment should be abandoned.

Interferon-Gamma, the Activated Macrophage, and Host Defense Against Microbial Challenge

Recent research on human macrophage activation has reemphasized the critical role of the lymphokine-secreting T cell in converting quiescent macrophages to efficient microbicidal phagocytes. Interferon-gamma, a key lymphokine secreted by antigen-triggered T4+ helper cells, is capable of inducing the macrophage to act against a diverse group of microbial targets, in particular, intracellular pathogens. In animal models, treatment with recombinant interferon-gamma is beneficial in systemic intracellular infections, and inhibition of endogenous interferon-gamma activity impairs host resistance. Trials in patients with cancer, leprosy, and the acquired immunodeficiency syndrome (AIDS) have shown that interferon-gamma can activate the mononuclear phagocyte in humans. This research and the identification of patients whose T cells fail to produce interferon-gamma properly has set the stage for evaluating the role of macrophage-activating immunotherapy using interferon-gamma in various human infectious diseases.

Killing of intracellular Leishmania donovani by lymphokine-stimulated human mononuclear phagocytes. Evidence that interferon-gamma is the activating lymphokine.

We have found that the crude lymphokines, which prime the human monocyte-derived macrophage to generate H2O2 and exert microbicidal activity against intracellular Leishmania donovani, are rich in interferon (IFN)-gamma (600-3,000 U/ml). To determine the role of this specific lymphocyte product in macrophage activation, lymphokines were pretreated with a monoclonal antibody that neutralizes human IFN-gamma. Antibody exposure completely abolished the capacity of both mitogen- and antigen-stimulated lymphokines to either enhance macrophage H2O2 release or induce leishmanicidal activity. In addition, partially purified and pure recombinant human IFN-gamma were as effective as crude lymphokines in activating macrophages, and 3 d of treatment with 300 U/ml resulted in a seven- to eightfold increase in H2O2 generation and the intracellular killing of both L. donovani promastigotes and amastigotes. The ability of crude lymphokines to induce monocytes and macrophages from a patient with chronic granulomatous disease to kill L. donovani promastigotes was similarly abrogated by anti-IFN-gamma antibody, and could also be achieved by IFN-gamma alone. These results suggest that IFN-gamma is the key macrophage-activating molecule present within human lymphokines, and indicate that IFN-gamma can enhance both the oxygen-dependent and -independent antiprotozoal mechanisms of human mononuclear phagocytes.

Single-Dose Liposomal Amphotericin B for Visceral Leishmaniasis in India

BACKGROUND Some 50% of patients with visceral leishmaniasis (kala-azar) worldwide live in the Indian state of Bihar. Liposomal amphotericin B is an effective treatment when administered in short courses. We wanted to determine whether the efficacy of a single infusion of liposomal amphotericin B was inferior to conventional parenteral therapy, consisting of 15 alternate-day infusions of amphotericin B deoxycholate. METHODS In this open-label study, we randomly assigned 412 patients in a 3:1 ratio to receive either liposomal amphotericin B (liposomal-therapy group) or amphotericin B deoxycholate (conventional-therapy group). Liposomal amphotericin B (at a dose of 10 mg per kilogram of body weight) was given once, and patients were discharged home 24 hours later. Amphotericin B deoxycholate, which was administered in 15 infusions of 1 mg per kilogram, was given every other day during a 29-day hospitalization. We determined the cure rate 6 months after treatment. RESULTS A total of 410 patients--304 of 304 patients (100%) in the liposomal-therapy group and 106 of 108 patients (98%) in the conventional-therapy group--had apparent cure responses at day 30. Cure rates at 6 months were similar in the two groups: 95.7% (95% confidence interval [CI], 93.4 to 97.9) in the liposomal-therapy group and 96.3% (95% CI, 92.6 to 99.9) in the conventional-therapy group. Adverse events in the liposomal-therapy group were infusion-related fever or rigors (in 40%) and increased anemia or thrombocytopenia (in 2%); such events in the conventional-therapy group were fever or rigors (in 64%), increased anemia (in 19%), and hypokalemia (in 2%). Nephrotoxicity or hepatotoxicity developed in no more than 1% of patients in each group. CONCLUSIONS A single infusion of liposomal amphotericin B was not inferior to and was less expensive than conventional therapy with amphotericin B deoxycholate. (ClinicalTrials.gov number, NCT00628719.)

Rapid accurate field diagnosis of Indian visceral leishmaniasis

BACKGROUND A firm diagnosis of visceral leishmaniasis (kala-azar) requires demonstration of the parasite in organ aspirates or tissue biopsy samples. The aim of this prospective study was to assess the diagnostic usefulness of non-invasive testing for antibody to the leishmanial antigen K39 by means of antigen-impregnated nitrocellulose paper strips adapted for use under field conditions. METHODS One drop of peripheral blood is applied to the hitrocellulose strip. Three drops of test buffer (phosphate-buffered saline plus bovine serum albumin) are added to the dried blood. The development of two visible bands indicates presence of IgG anti-K39. 323 consecutive patients with suspected kala-azar referred to two specialist units in India, and 25 healthy controls, provided fingerstick blood samples for the test. Spleen aspirates were taken from 250 patients. FINDINGS Kala-azar was confirmed by microscopy of spleen-aspirate smears in 127 patients. The K39 strip test was positive in all 127; the estimated sensitivity was therefore 100% (95% CI 98-100). Four patients had positive strip tests but negative aspirate smears; all four responded to treatment for leishmaniasis. 217 individuals, including the 25 healthy controls, 73 patients with malaria or tuberculosis, and 119 spleen-aspirate-negative patients who had presumed malaria or cirrhosis (79) or no final diagnosis (40), had negative strip-test results. None of the 119 aspirate-negative patients developed evidence of kala-azar during 3-6 months of follow-up. The estimated specificity of the strip test was 98% (95-100; 217/221). INTERPRETATION Detection of anti-K39 by immunochromatographic strip testing is a rapid and non-invasive method of diagnosing kala-azar, which has good sensitivity and specificity and is well suited for use in field conditions.

The protean manifestations of mycoplasma pneumoniae infection in adults

Mycoplasma pneumoniae is a well recognized respiratory pathogen in children and young adults. In addition, M. pneumoniae infections may also involve other organ systems. Reviewed here are the various clinical syndromes in adults caused by this infectious agent, with emphasis on those which have recently been seen at The New York Hospital. Two previously unreported manifestations of M. pneumoniae infection, cranial nerve mononeuropathy and hepatitis, are described, and the laboratory methods for diagnosis are discussed.

Trial of oral miltefosine for visceral leishmaniasis

BACKGROUND There is no effective oral treatment for visceral leishmaniasis (kala-azar), a disseminated intracellular protozoal infection that occurs worldwide. Miltefosine, an alkyl phospholipid developed as an oral antineoplastic agent, is active against visceral infection in animal models. We tested safety, tolerance, and efficacy of miltefosine in kala-azar. METHODS Oral doses of miltefosine were given to six groups of five Indian men for 28 days: 50 mg every second day (group 1), 100 mg every second day (group 2), 100 mg/day (group 3), 150 mg/day (group 4), 200 mg/day (group 5), and 250 mg/day (group 6). Assessment for apparent cure--taken as an afebrile state with decreased spleen size and a splenic-aspirate parasite-density score of 0--was done on days 14 and 28. Definitive cure at 8 months required a parasite-free bone-marrow aspirate and no clinical evidence of relapse. FINDINGS 21 of 30 patients were apparently cured on day 14. Transient episodes of vomiting and diarrhoea, were common during weeks 1-2 and were seen in 22 patients. Four other patients in groups 5 and 6 had miltefosine withdrawn after 7-10 days because of vomiting. One patient in group 6 developed renal insufficiency and severe diarrhoea and died on day 21. On day 28, all 29 remaining patients were apparently cured. By 8 months, seven of ten patients in groups 1 and 2 had relapsed; however, 18 of 19 patients treated daily (groups 3-6) appeared to be cured. Among the 21 definitive cures were the four patients treated for 10 days or less and 12 for whom previous therapy with pentavalent antimony had failed. INTERPRETATION Treatment with miltefosine at 100-150 mg/day for 4 weeks has promise as an effective oral treatment of visceral leishmaniasis including antimony-resistant infection.

Interleukin-10 (IL-10) in Experimental Visceral Leishmaniasis and IL-10 Receptor Blockade as Immunotherapy

ABSTRACT Interleukin-10 (IL-10) is thought to promote intracellular infection, including human visceral leishmaniasis, by disabling Th1 cell-type responses and/or deactivating parasitized tissue macrophages. To develop a rationale for IL-10 inhibition as treatment in visceral infection, Th1 cytokine-driven responses were characterized in Leishmania donovani-infected BALB/c mice in which IL-10 was absent or overexpressed or its receptor (IL-10R) was blockaded. IL-10 knockout and normal mice treated prophylactically with anti-IL-10R demonstrated accelerated granuloma assembly and rapid parasite killing without untoward tissue inflammation; IL-12 and gamma interferon mRNA expression, inducible nitric oxide synthase reactivity, and responsiveness to antimony chemotherapy were also enhanced in knockout mice. In IL-10 transgenic mice, parasite replication was unrestrained, and except for antimony responsiveness, measured Th1 cell-dependent events were all initially impaired. Despite subsequent granuloma assembly, high-level infection persisted, and antimony-treated transgenic mice also relapsed. In normal mice with established infection, anti-IL-10R treatment was remarkably active, inducing near-cure by itself and synergism with antimony. IL-10s deactivating effects regulate outcome in experimental visceral leishmaniasis, and IL-10R blockade represents a potential immuno- and/or immunochemotherapeutic approach in this infection.