Treatment of atypical leishmaniasis with interferon gamma resulting in progression of Kaposi's sarcoma in an AIDS patient

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.

Immunomodulatory Therapy of Visceral Leishmaniasis in Human Immunodeficiency Virus-Coinfected Patients

Patients with visceral leishmaniasis (VL)–human immunodeficiency virus (HIV) coinfection experience increased drug toxicity and treatment failure rates compared to VL patients, with more frequent VL relapse and death. In the era of VL elimination strategies, HIV coinfection is progressively becoming a key challenge, because HIV-coinfected patients respond poorly to conventional VL treatment and play an important role in parasite transmission. With limited chemotherapeutic options and a paucity of novel anti-parasitic drugs, new interventions that target host immunity may offer an effective alternative. In this review, we first summarize current views on how VL immunopathology is significantly affected by HIV coinfection. We then review current clinical and promising preclinical immunomodulatory interventions in the field of VL and discuss how these may operate in the context of a concurrent HIV infection. Caveats are formulated as these interventions may unpredictably impact the delicate balance between boosting of beneficial VL-specific responses and deleterious immune activation/hyperinflammation, activation of latent provirus or increased HIV-susceptibility of target cells. Evidence is lacking to prioritize a target molecule and a more detailed account of the immunological status induced by the coinfection as well as surrogate markers of cure and protection are still required. We do, however, argue that virologically suppressed VL patients with a recovered immune system, in whom effective antiretroviral therapy alone is not able to restore protective immunity, can be considered a relevant target group for an immunomodulatory intervention. Finally, we provide perspectives on the translation of novel theories on synergistic immune cell cross-talk into an effective treatment strategy for VL–HIV-coinfected patients.

Leishmaniasis-HIV coinfection: current challenges

Leishmaniasis – human immunodeficiency virus (HIV) coinfection can manifest itself as tegumentary or visceral leishmaniasis. Almost 35 countries have reported autochthonous coinfections. Visceral leishmaniasis is more frequently described. However, usual and unusual manifestations of tegumentary leishmaniasis have been reported mainly in the Americas, but the real prevalence of Leishmania infection in HIV-infected patients is not clear. Regarding the clinical manifestations, there are some reports showing unusual manifestations in visceral leishmaniasis and tegumentary leishmaniasis in HIV-infected patients; yet, the usual manifestations are more frequent. Leishmaniasis diagnosis relies on clinical methods, but serological tests are used to diagnose visceral leishmaniasis despite them having a low sensitivity to tegumentary leishmaniasis. The search for the parasite is used to diagnose both visceral leishmaniasis and tegumentary leishmaniasis. Nevertheless, in HIV-infected patients, the sensitivity of serology is very low. Drugs available to treat leishmaniasis are more restricted and cause severe side effects. Furthermore, in HIV-infected patients, these side effects are more prominent and relapses and lethality are more recurrent. In this article, we discuss the current challenges of tegumentary leishmaniasis and visceral leishmaniasis–HIV infection, focusing mainly on the clinical manifestations, diagnosis, and treatment of leishmaniasis.

Atypical manifestations of visceral leishmaniasis in patients with HIV in north Ethiopia: a gap in guidelines for the management of opportunistic infections in resource poor settings

In regions where it is endemic, visceral leishmaniasis is an important opportunistic infectious disease in people living with HIV. Typically, clinical presentation of visceral leishmaniasis includes chronic fever, hepatosplenomegaly, and weight loss. In Leishmania infantum endemic regions in Europe, atypical visceral leishmaniasis presentations have been well documented, with almost every possible organ involved. However, such reports are rare in Leishmania donovani endemic regions such as east Africa. In this Personal View, we describe the various atypical disease presentations in patients screened as part of an HIV and visceral leishmaniasis clinical trial in north Ethiopia, where up to 40% of patients with visceral leishmaniasis are co-infected with HIV. Atypical presentations such as these are not covered in clinical guidelines used in these settings. Apart from the lack of diagnostic facilities, this gap contributes to the underdiagnosis of atypical visceral leishmaniasis, with associated morbidity and mortality. Involvement of clinicians experienced with the management of HIV and visceral leishmaniasis co-infection in the development of HIV clinical guidelines in affected regions is warranted.

Angiogenic effects of extracellular human immunodeficiency virus type 1 Tat protein and its role in the pathogenesis of AIDS-associated Kaposi's sarcoma

The Tat protein of human immunodeficiency virus (HIV) type 1 is a transactivator of viral gene expression that is required for virus replication and spread. Moreover, Tat is released by acutely HIV-infected cells via a leaderless secretory pathway and in a biologically active form that exerts effects on both HIV-infected and uninfected cells from different organs and systems. This review focuses on the activities of extracellular Tat protein on endothelial cells, on angiogenesis, and on the pathogenesis of AIDS-associated angioproliferative diseases such as Kaposi's sarcoma. In particular, we discuss results from different groups indicating that Tat mimics the proangiogenic activities of extracellular matrix molecules and that it enhances the effects of angiogenic factors.

Visceral leishmaniasis in human immunodeficiency virus (HIV)-infected and non-HIV-infected patients. A comparative study

Visceral leishmaniasis is an endemic infection in Mediterranean countries, where it has become a frequent complication of acquired immunodeficiency syndrome (AIDS). The incidence of visceral leishmaniasis is increasing in Spain due to human immunodeficiency virus (HIV)-related cases, but some aspects of its epidemiology, clinical features, and management remain unknown. In addition, no comparative clinical studies about the disease in HIV-infected and non-HIV-infected patients have been reported. During a 24-year period, 120 cases of visceral leishmaniasis were diagnosed at our institution and 80 (66%) were associated with HIV infection. The mean age at diagnosis was higher in HIV-infected that in non-HIV-infected patients (33.2 versus 23.2 yr; p = 0.002), but the male/female ratio was similar in both groups. The main risk factor for HIV infection was intravenous drug abuse (78.7%). The clinical presentation of leishmaniasis was similar in both groups, but HIV-infected patients had a lower frequency of splenomegaly than HIV-negative individuals (80.8% versus 97.4%; p = 0.02). HIV-infected patients had a greater frequency and degree of leukopenia, lymphocytopenia, and thrombocytopenia. Most of them were profoundly immunosuppressed (mean CD4+ lymphocyte count, 90 cells/mm3) at the time of diagnosis of leishmaniasis, and 53.7% had AIDS. The sensitivity of serologic studies for Leishmania was significantly lower in HIV-infected than in non-HIV-infected patients (50% versus 80%; p < 0.001), but the diagnostic yield of bone marrow aspirate (67.1% versus 79.4%) and bone marrow culture (62.9% versus 66.6%) was similar in both groups. After initial treatment, the response rate was significantly lower in HIV-infected than in non-HIV-infected individuals (54.8% versus 89.7%; p = 0.001). The relapse rate was 46.2% and 7.5%, respectively (p < 0.001). Secondary prophylaxis with antimonial compounds or amphotericin B seems to be useful in preventing relapses in HIV-infected patients. The mortality rate was higher (53.7% versus 7.5%; p < 0.001) and the median survival time shorter (25 versus > 160 mo; p < 0.001) in AIDS patients than in HIV-negative individuals. Although leishmaniasis could contribute to death in a significant number of HIV-infected patients, it was the main cause of death in only a few of them. The CD4+ lymphocyte count and the use of highly active antiretroviral therapy and secondary prophylaxis for leishmaniasis were the most significant prognostic factors for survival in AIDS patients. Visceral leishmaniasis behaves as an opportunistic infection in HIV-infected individuals and should be considered as an AIDS-defining disease.

Leishmania-HIV interaction: immunopathogenic mechanisms

Both Leishmania and the human immunodeficiency virus (HIV) can infect and multiply in macrophages, and both can dysregulate the immune system. Recent studies indicate that Leishmania can induce the activation of HIV in latently infected monocytic and T cells. Moreover, HIV can enhance intracellular growth of Leishmania in macrophages. Here, Dawit Wolday and colleagues examine the mechanisms that might be involved in the immunopathogenesis of Leishmania- HIV co-infection.

IFN-γ Induces Endothelial Cells to Proliferate and to Invade the Extracellular Matrix in Response to the HIV-1 Tat Protein: Implications for AIDS-Kaposi’s Sarcoma Pathogenesis

Previous studies indicated that the Tat protein of HIV functions as a progression factor in Kaposi’s sarcoma (KS), an angioproliferative disease common and aggressive in HIV-1-infected individuals (AIDS-KS). In particular, Tat that is released by infected cells stimulates the growth and invasion of spindle cells of endothelial origin derived from KS lesions (KS cells). Other work suggested that inflammatory cytokines may act as initiating factors in KS since they induce normal endothelial cells to acquire the same phenotype and functional features of KS cells, including the responsiveness to Tat. In this study, we show that among the inflammatory cytokines increased in AIDS-KS lesions, IFN-γ alone is sufficient to induce endothelial cells to proliferate and to invade the extracellular matrix in response to Tat. This is because IFN-γ up-regulates the expression and activity of the receptors for Tat identified as the integrins α5β1 and αvβ3. These results suggest that, by triggering Tat effects, IFN-γ plays a major role in AIDS-KS pathogenesis.

Interferons in dermatology. Present-day standard

Since the first clinical trials in the early 1980s with recombinant interferon, it was possible to show for a variety of indications that cytokines, especially interferons, at certain doses and at respective intervals, when applied in combination with other pharmaceutical compounds open new powerful therapeutic possibilities. Worldwide, recombinant interferon is licensed, especially in dermato-oncology, for the indication of HIV-associated Kaposi's sarcoma, cutaneous T-cell lymphoma, and recently for adjuvant therapy of high-risk malignant melanoma. Recombinant interferon is at present not licensed for dermatologic indication (septic granulomatosis). At the end of our century the indication spectrum for interferons as monotherapy and as combination therapy will undoubtedly be extended. Larger and controlled studies will prove the importance of interferons in dermato-oncology as well as in inflammatory and infectious dermatoses. The combination of interferons with standard therapies will surely be of the utmost importance in dermatotherapy.

Kaposi's sarcoma: a result of the interplay among inflammatory cytokines, angiogenic factors and viral agents

Kaposi's sarcoma (KS) is an angioproliferative disease occurring in 4 clinic-epidemiologic forms. Although the AIDS-associated KS (AIDS-KS) is the most aggressive, all forms of KS share the same immunological and histopathological features suggesting common etiological and pathogenic factors. Recent data indicate that at least in early stage KS is not a real sarcoma but an angiohyperplastic-inflammatory lesion mediated by inflammatory cytokines and angiogenic factors, that is triggered or amplified by infection with human herpesvirus-8. In addition, the human immunodeficiency virus type-1 Tat protein appears to be responsible for the higher grade of aggressiveness of AIDS-KS as compared to the other forms of KS. However, given time, reactive KS may progress to a sarcoma as suggested by evidence of monoclonality in late-nodular lesions.

γ-Interferon Production in Peripheral Blood Mononuclear Cells and Tumor Infiltrating Lymphocytes From Kaposi's Sarcoma Patients: Correlation With the Presence of Human Herpesvirus-8 in Peripheral Blood Mononuclear Cells and Lesional Macrophages

Evidence indicates that, at least in the early stage, Kaposi's sarcoma (KS) is a cytokine-mediated disease and that it is consistently associated with a novel herpesvirus termed human herpesvirus-8 (HHV-8). To gain insights into the mechanisms by which cytokines and HHV-8 may cooperate in disease pathogenesis, we examined the phenotype, the Th1 (γ-interferon [γIFN]) and Th2 (interleukin-4 [IL-4]) cytokine profile and the presence of HHV-8 in peripheral blood mononuclear cells (PBMC), tumor-infiltrating lymphocytes (TIL), and spindle cell cultures derived from skin lesions of patients affected by classical KS (C-KS) and acquired immunodeficiency syndrome (AIDS)-associated KS (AIDS-KS). TIL and spindle cell cultures were examined at day 0 or after culture in conditioned media from activated T cells (TCM) that contain the same cytokines increased in KS tissues. No differences were found in the immunophenotype of PBMC from C-KS patients versus controls, except for AIDS-KS patients who showed a T-CD8+ expansion. However, a preferential infiltration of T-CD8+ cells was found in all KS lesions examined, which was maintained after culture of TIL in TCM. γIFN production was found in both PBMC and cultures derived from all KS examined; some IL-4 positive supernatants were found only in three AIDS-KS cases. Uninvolved skin did not show appreciable lymphocyte infiltration or cytokine production. The culture conditions of the lesional skin allowed also the appearance of adherent, spindle-like cells bearing markers of tissue macrophages. Finally, most or all of the PBMC, lesions, and macrophagic cell cultures from the skin lesions were found to be positive for HHV-8 infection by nested polymerase chain reaction (PCR). These findings indicate that patients with KS express a Th1 phenotype with a prevalent γIFN production, likely accounted for by the local T-CD8+ infiltration. By analogy with other viral infections (ie, Epstein-Barr virus), this suggests that in loco recruitment of lymphoid cells and the subsequent γIFN production may be in response to or elicited by HHV-8 that was found in both PBMC and macrophagic cell cultures from the lesions of the same patients.

γ-Interferon Production in Peripheral Blood Mononuclear Cells and Tumor Infiltrating Lymphocytes From Kaposi's Sarcoma Patients: Correlation With the Presence of Human Herpesvirus-8 in Peripheral Blood Mononuclear Cells and Lesional Macrophages

Evidence indicates that, at least in the early stage, Kaposi's sarcoma (KS) is a cytokine-mediated disease and that it is consistently associated with a novel herpesvirus termed human herpesvirus-8 (HHV-8). To gain insights into the mechanisms by which cytokines and HHV-8 may cooperate in disease pathogenesis, we examined the phenotype, the Th1 (γ-interferon [γIFN]) and Th2 (interleukin-4 [IL-4]) cytokine profile and the presence of HHV-8 in peripheral blood mononuclear cells (PBMC), tumor-infiltrating lymphocytes (TIL), and spindle cell cultures derived from skin lesions of patients affected by classical KS (C-KS) and acquired immunodeficiency syndrome (AIDS)-associated KS (AIDS-KS). TIL and spindle cell cultures were examined at day 0 or after culture in conditioned media from activated T cells (TCM) that contain the same cytokines increased in KS tissues. No differences were found in the immunophenotype of PBMC from C-KS patients versus controls, except for AIDS-KS patients who showed a T-CD8+ expansion. However, a preferential infiltration of T-CD8+ cells was found in all KS lesions examined, which was maintained after culture of TIL in TCM. γIFN production was found in both PBMC and cultures derived from all KS examined; some IL-4 positive supernatants were found only in three AIDS-KS cases. Uninvolved skin did not show appreciable lymphocyte infiltration or cytokine production. The culture conditions of the lesional skin allowed also the appearance of adherent, spindle-like cells bearing markers of tissue macrophages. Finally, most or all of the PBMC, lesions, and macrophagic cell cultures from the skin lesions were found to be positive for HHV-8 infection by nested polymerase chain reaction (PCR). These findings indicate that patients with KS express a Th1 phenotype with a prevalent γIFN production, likely accounted for by the local T-CD8+ infiltration. By analogy with other viral infections (ie, Epstein-Barr virus), this suggests that in loco recruitment of lymphoid cells and the subsequent γIFN production may be in response to or elicited by HHV-8 that was found in both PBMC and macrophagic cell cultures from the lesions of the same patients.

Human immunodeficiency virus type 1 (HIV-1) infection of herpesvirus saimiri-immortalized human CD4-positive T lymphoblastoid cells: evidence of enhanced HIV-1 replication and cytopathic effects caused by endogenous interferon-gamma

Herpesvirus saimiri (HVS) is a nonhuman primate gamma herpesvirus which can immortalize human T lymphocytes similar to Epstein-Barr virus immortalization of B cells. The HVS-immortalized T cell lines can be cloned and they remain functional, including susceptibility of CD4 expressing T cells to infection with human immunodeficiency virus type 1 (HIV-1). In this report, we have used five such HVS-transformed CD4-positive T cell clones to reevaluate the role of endogenous interferon gamma (IFN gamma) in HIV-1 replication in T cells. All five clones had similar phenotypes; and four clones constitutively produced IFN gamma and one clone did not. All five clones could be efficiently infected with HIV-1. HIV-1 infection of the IFN gamma-positive cells also upregulated IFN gamma mRNA production and IFN gamma secretion but not production of IL-2 or IL-4. In contrast, infection of IFN gamma-negative cells did not induce IFN gamma, IL-2, or IL-4. Exposure to anti-IFN gamma antibodies after HIV-1 infection significantly reduced virus production and inhibited virus-induced death of IFN gamma-positive cells but had no effect on IFN gamma-negative cells. We conclude that in CD4-positive T lymphocytes immortalized by HVS endogenous IFN gamma does not inhibit HIV-1 but enhances HIV-1 replication and cytolysis. The potential augmenting effects of IFN gamma on HIV-1 replication in CD4-positive T cells recommend caution in a therapeutic use of this cytokine in AIDS.

Leishmania and human immunodeficiency virus coinfection: the first 10 years

Over 850 Leishmania-human immunodeficiency virus (HIV) coinfection cases have been recorded, the majority in Europe, where 7 to 17% of HIV-positive individuals with fever have amastigotes, suggesting that Leishmania-infected individuals without symptoms will express symptoms of leishmaniasis if they become immunosuppressed. However, there are indirect reasons and statistical data demonstrating that intravenous drug addiction plays a specific role in Leishmania infantum transmission: an anthroponotic cycle complementary to the zoonotic one has been suggested. Due to anergy in patients with coinfection, L. infantum dermotropic zymodemes are isolated from patient viscera and a higher L. infantum phenotypic variability is seen. Moreover, insect trypanosomatids that are currently considered nonpathogenic have been isolated from coinfected patients. HIV infection and Leishmania infection each induce important analogous immunological changes whose effects are multiplied if they occur concomitantly, such as a Th1-to-Th2 response switch; however, the consequences of the viral infection predominate. In fact, a large proportion of coinfected patients have no detectable anti-Leishmania antibodies. The microorganisms share target cells, and it has been demonstrated in vitro how L. infantum induces the expression of latent HIV-1. Bone marrow culture is the most useful diagnostic technique, but it is invasive. Blood smears and culture are good alternatives. PCR, xenodiagnosis, and circulating-antigen detection are available only in specialized laboratories. The relationship with low levels of CD4+ cells conditions the clinical presentation and evolution of disease. Most patients have visceral leishmaniasis, but asymptomatic, cutaneous, mucocutaneous, diffuse cutaneous, and post-kala-azar dermal leishmaniasis can be produced by L. infantum. The digestive and respiratory tracts are frequently parasitized. The course of coinfection is marked by a high relapse rate. There is a lack of randomized prospective treatment trials; therefore, coinfected patients are treated by conventional regimens. Prophylactic therapy is suggested to be helpful in preventing relapses.

In vivo efficacy of oral and intralesional administration of 2-substituted quinolines in experimental treatment of new world cutaneous leishmaniasis caused by Leishmania amazonensis

The antileishmanial efficacies of 2-n-propylquinoline, chimanines B and D, 2-n-pentylquinoline, 2-phenylquinoline, 2-(3,4-methylenedioxyphenylethyl) quinoline, and two total alkaloidal extracts of Galipea longiflora were evaluated in BALB/c mice infected with Leishmania amazonensis or Leishmania venezuelensis. Animals were treated for 4 to 6 weeks postinfection with a quinoline by the oral route at 50 mg/kg of body weight twice daily for 15 days or by five intralesional injections at intervals of 4 days with a quinoline at 50 mg/kg of body weight. The reference drug, N-methylglucamine antimonate (Glucantime), was administered by subcutaneous or intralesional injection (regimens of 14, 28, or 56 mg of pentavalent antimony [Sbv] per kg of body weight daily). Twice-daily oral treatment with chimanine B at 50 mg/kg resulted in a decrease in lesion weight by 70% (P < 0.001) and a decrease in the parasite loads by 95% (P < 0.001). Five injections of chimanine B at intervals of 4 days reduced the lesion weight by 74% and the parasite loads in the lesion by 90% compared with the values for the group of untreated mice. Subcutaneous administration of N-methylglucamine antimonate at 28 mg of Sbv kg per day for 15 days reduced the parasite burden by 95% (P < 0.001), and five intralesional injections at the same concentration reduced the parasite burden by 96% (P < 0.001). Other 2-substituted quinolines, 2-n-propylquinoline administered by the oral and intralesional routes, 2-phenylquinoline administered by the oral route, 2-n-pentylquinoline administered by intralesional injection, and two total alkaloidal extracts of G. longiflora administered by the oral route, had intermediate effects. These findings suggest that chimanine B may be chosen as a lead molecule in the development of oral therapy against leishmaniasis.