Visceral leishmaniasis as an independent cause of high immune activation, T-cell senescence, and lack of immune recovery in virologically suppressed HIV-1-coinfected patients

Persistent T cell unresponsiveness associated with chronic visceral leishmaniasis in HIV-coinfected patients

A large proportion of HIV-coinfected visceral leishmaniasis (VL-HIV) patients exhibit chronic disease with frequent VL recurrence. However, knowledge on immunological determinants underlying the disease course is scarce. We longitudinally profiled the circulatory cellular immunity of an Ethiopian HIV cohort that included VL developers. We show that chronic VL-HIV patients exhibit high and persistent levels of TIGIT and PD-1 on CD8+/CD8- T cells, in addition to a lower frequency of IFN-γ+ TIGIT- CD8+/CD8- T cells, suggestive of impaired T cell functionality. At single T cell transcriptome and clonal resolution, the patients show CD4+ T cell anergy, characterised by a lack of T cell activation and lymphoproliferative response. These findings suggest that PD-1 and TIGIT play a pivotal role in VL-HIV chronicity, and may be further explored for patient risk stratification. Our findings provide a strong rationale for adjunctive immunotherapy for the treatment of chronic VL-HIV patients to break the recurrent disease cycle.

Vaccine value profile for leishmaniasis

Leishmania infections are global, occurring in 98 countries and all World Health Organization (WHO) regions with 600 million to 1 billion people at risk of infection. Visceral leishmaniasis is associated with almost 20,000 reported deaths annually, with children under 5 years of age being at the greatest risk of mortality. Amongst WHO-recognised Neglected Tropical Diseases (NTDs), leishmaniasis is one of the most important in terms of mortality and morbidity. With an increasing global burden of disease and a growing threat from climate change, urbanisation and drug resistance, there remains an imperative to develop leishmaniasis vaccines. New tools to understand correlates of protection and to assess vaccine efficacy are being developed to ease the transition into larger scale efficacy trials or provide alternate routes to licensure. Early indications suggest a diverse portfolio of manufacturers exists in endemic countries with an appetite to develop leishmaniasis vaccines. This Vaccine Value Profile (VVP) provides a high-level, comprehensive assessment of the currently available data to inform the potential public health, economic, and societal value of leishmaniasis vaccines. The leishmaniasis VVP was developed by a working group of subject matter experts from academia, public health groups, policy organizations, and non-profit organizations. All contributors have extensive expertise on various elements of the leishmaniasis VVP and have collectively described the state of knowledge and identified the current gaps. The VVP was developed using only existing and publicly available information.

T-cell activation, senescence, and exhaustion in asymptomatic HIV/Leishmania infantum co-infection

Background

Leishmania infantum is an opportunistic parasitic infection. An immunocompromised state increases the risk of converting asymptomatic infection to symptomatic visceral leishmaniasis (VL), which has a ~5% fatality rate even with treatment. HIV coinfection increases the risk of death from VL.

Methods

A cross-sectional study was performed between 2014 and 2016 to determine the prevalence of L. infantum infection in HIV positive subjects residing in the state of Rio Grande do Norte, Brazil (n=1,372) and of these a subgroup of subjects were followed longitudinally. Subsequent incident cases of VL were ascertained from a public health database through 2018. A subgroup (n=69) of the cross-sectional study subjects was chosen to assess immune status (T cell activation, senescence, exhaustion) and outcome. The data were compared between asymptomatic HIV+/L. infantum+ (HIV/Leish), symptomatic visceral leishmaniasis (VL), recovered VL, DTH+ (Delayed-Type Hypersensitivity response - Leishmanin skin test), AIDS/VL, HIV+ only (HIV+), and Non-HIV/Non L. infantum infection (control subjects).

Results

The cross-sectional study showed 24.2% of HIV+ subjects had positive anti-IgG Leishmania antibodies. After 3 years, 2.4% (8 of 333) of these HIV/Leish coinfected subjects developed AIDS/VL, whereas 1.05% (11 of 1,039) of HIV subjects with negative leishmania serology developed AIDS/VL. Poor adherence to antiretroviral therapy (p=0.0008) or prior opportunistic infections (p=0.0007) was associated with development of AIDS/VL. CD4+ (p=0.29) and CD8+ (p=0.38) T cells counts or viral load (p=0.34) were similar between asymptomatic HIV/Leish and HIV subjects. However, activated CD8+CD38+HLA-DR+ T cells were higher in asymptomatic HIV/Leish than HIV group. Likewise, senescent (CD57+) or exhausted (PD1+) CD8+ T cells were higher in asymptomatic HIV/Leish than in AIDS/VL or HIV groups.

Conclusion

Although asymptomatic HIV/Leish subjects had normal and similar CD4+ and CD8+ T cells counts, their CD8+T cells had increased activation, senescence, and exhaustion, which could contribute to risk of developing VL.

Recurrent visceral leishmaniasis relapses in HIV co-infected patients are characterized by less efficient immune responses and higher parasite load

Visceral leishmaniasis (VL) and HIV co-infection (VL/HIV) has emerged as a significant public health problem in Ethiopia, with up to 30% of patients with VL co-infected with HIV. These patients suffer from recurrent VL relapses and increased mortality. Those with a previous history of VL relapses (recurrent VL/HIV) experience increased VL relapses as compared to patients with HIV presenting with their first episode of VL (primary VL/HIV). Our aim was to identify drivers that account for the higher rate of VL relapses in patients with recurrent VL/HIV (n = 28) as compared to primary VL/HIV (n = 21). Our results show that the relapse-free survival in patients with recurrent VL/HIV was shorter, that they had higher parasite load, lower weight gain, and lower recovery of all blood cell lineages. Their poorer prognosis was characterized by lower production of IFN-gamma, lower CD4+ T cell counts, and higher expression of programmed cell death protein 1 (PD1) on T cells.

Occurrence and Molecular Characterization of Cryptosporidium Infection in HIV/Aids Patients in Algeria

The estimated prevalence rate of adults living with HIV infection in MENA is one of the lowest in the world. To date, no data on the genetic characteristics of Cryptosporidium isolates from HIV/AIDS patients in Algeria were available. This study aimed to identify Cryptosporidium species and subtype families prevalent in Algerian HIV-infected patients and contribute to the molecular epidemiology mapping of Cryptosporidium in the MENA region. A total of 350 faecal specimens from HIV/AIDS patients were analysed using microscopy, and a Cryptosporidium infection was identified from 33 samples, with 22 isolates successfully sequencing and confirming species and subtypes. Based on sequence analysis, 15 isolates were identified as C. parvum with family subtypes IIa (n = 7) and IId (n = 8), while five were identified as C. hominis (family subtypes Ia (n = 2) and Ib (n = 3)) and two as C. felis. The C. parvum subtype families IIa and IId predominated, suggesting potential zoonotic transmission. More extensive sampling of both humans and farm animals, especially sheep, goats and calves, as well as a collection of epidemiological data are needed for a better understanding of the sources of human C. parvum infections in Algeria.

New world Leishmania spp. infection in people living with HIV: Concerns about relapses and secondary prophylaxis

Coinfection with the human immunodeficiency virus (HIV) and Leishmania impairs immune responses, increases treatment failure and relapse rates in patients with American tegumentary leishmaniasis (ATL), as well as visceral leishmaniasis (VL). There is insufficient data on the treatment, relapse, and secondary prophylaxis in patients coinfected with HIV/Leishmania in Brazil. This study investigated patients with HIV/ATL and HIV/VL to describe the outcome of leishmaniasis in patients assisted at a referral hospital of Brazilian midwestern region. Patients with HIV/ATL (n = 21) mainly presented cutaneous diseases (76.2%) with an overall relapse rate of 28.57% after treatment, whereas HIV/VL (n = 28) patients accounted for 17.5% of the cases. The counts of CD4⁺ T cells and CD8⁺ T cells and the CD4⁺/CD8⁺ cell ratios at diagnosis or relapses were not significantly different between relapsing and non-relapsing patients. Patients with HIV/ATL or HIV/VL showed high levels of activation markers in CD4⁺ and CD8⁺ T cells. The regular use of highly active antiretroviral therapy (HAART) and viral load at the time of diagnosis did not influence the relapse rates. Relapses occurred in 36.4% (4/11) of the patients with HIV/VL receiving secondary prophylaxis and in 5.9% (1/17) of the patients who did not receive secondary prophylaxis (p = 0.06). These data are relevant for the therapeutic management of the patients coinfected with HIV/Leishmania.

An update on the clinical pharmacology of miltefosine in the treatment of leishmaniasis

Miltefosine is an alkylphosphocholine agent with a broad spectrum of antiparasitic properties. For over two decades, miltefosine has remained the only oral drug licensed and used in the treatment of the neglected tropical disease, leishmaniasis. The last extensive review of the pharmacology of miltefosine was published in 2012. Additional data on the clinical pharmacokinetics (PK) and pharmacodynamics (PD) of miltefosine have become available in the last decade, and there are ongoing and future studies in this area. Miltefosine PK are characterized by slow absorption and elimination, resulting in accumulation of drug in plasma until the end of treatment. Several recent studies established exposure-response relationships for various regimens of miltefosine in the treatment of visceral and cutaneous leishmaniasis, leading to the identification of PK parameters predictive of clinical relapse and outcome. This review provides an update on the most recent developments in the area of clinical pharmacology of miltefosine, including a discussion of the current dosing regimens.

Impaired Thymic Output Can Be Related to the Low Immune Reconstitution and T Cell Repertoire Disturbances in Relapsing Visceral Leishmaniasis Associated HIV/AIDS Patients

Background: Visceral leishmaniasis/HIV-co-infected patients (VL/HIV) accounts for around 8% of VL reported cases in Brazil. Relapses of Leishmania infection after anti-leishmanial treatment constitute a great challenge in the clinical practice because of the disease severity and drug resistance. We have shown that non-relapsing-VL/HIV (NR-) evolved with increase of CD4⁺ T-cell counts and reduction of activated CD4⁺ and CD8⁺ T cells after anti-leishmanial treatment. This immune profile was not observed in relapsing-VL/HIV patients (R-), indicating a more severe immunological compromising degree. Elevated activation status may be related to a deficient immune reconstitution and could help to explain the frequent relapses in VL/HIV co-infection. Our aim was to evaluate if this gain of T cells was related to changes in the peripheral TCRVβ repertoire and inflammatory status, as well as the possible thymus involvement in the replenishment of these newly formed T lymphocytes.

Methods: VL/HIV patients, grouped into non-relapsing (NR- = 6) and relapsing (R- = 12) were evaluated from the active phase up to 12 months post-treatment (mpt). HIV-infected patients (non-VL) and healthy subjects (HS) were included. The TCRVβ repertoire was evaluated ex vivo by flow cytometry, whereas the plasmatic cytokine levels were assessed by Luminex assay. To evaluate the thymic output, DNA was extracted from PBMCs for TCR rearrangement excision circles (TREC) quantification by qPCR.

Results: VL/HIV cases presented an altered mobilization profile (expansions or retractions) of the TCRVβ families when compared to HS independent of the follow-up phase (p < 0.05). TCRVβ repertoire on CD4⁺ T-cells was more homogeneous in the NR-VL/HIV cases, but heterogeneous on CD8⁺ T-cells, since different Vβ-families were mobilized. NR-VL/HIV had the inflammatory pattern reduced after 6 mpt. Importantly, VL/HIV patients showed number of TREC copies lower than controls during all follow-up. An increase of recent thymic emigrants was observed in NR-VL/HIV individuals at 10 mpt compared to R- patients (p < 0.01), who maintained lower TREC contents than the HIV controls.

Conclusions: VL/HIV patients that maintain the thymic function, thus generating new T-cells, seem able to replenish the T lymphocyte compartment with effector cells, then enabling parasite control.

Contribution of Leishmania braziliensis antigen-specific CD4+ T, CD8+ T, NK and CD3+CD56+NKT cells in the immunopathogenesis of cutaneous leishmaniasis patients: Cytotoxic, activation and exhaustion profiles

The pathogenesis of cutaneous leishmaniasis (CL) caused by Leishmania (Viannia) braziliensis is dictated mainly by the immune-mediated-tissue inflammation developed. The understanding of the immunological mechanisms that generate tissue damage or resolution of lesions is the key to the development of effective vaccine protocols and proper therapeutic schemes. It is clear that the specific immune response mediated by T cells is responsible for the beneficial outcome of the disease, however, the roles of CD4+ T, CD8+ T, NK and NKT cell subpopulations in immunopathogenesis of CL need to be elucidated. Peripheral blood cells from patients before, during and after the antimonial therapy, as well as healthy individuals (HI) were cultured with (LbAgS) or without (NS) L. braziliensis antigens (LbAg). Afterwards, the frequencies of LbAg-specific-cytotoxic CD8+ T, CD4+ T, NK and CD3+CD56+ NKT cells, as well as their activation and exhaustion profiles, were defined by flow cytometry. We observed higher frequencies of CD8+ T, NK and CD3+CD56+ NKT cells and lower frequencies of CD4+ T lymphocytes in LbAgS cell cultures from patients before treatment. The specific response to LbAg resulted in an expansion of cytotoxic-activated CD4+ T, CD8+ T, and NK cells, before and during treatment, indicating specificity in the response by these cells against L. braziliensis. Furthermore, comparing the differences of frequencies of cytotoxic-activated CD4+T, CD8+T, and NK cells, among before and during treatment patients and HI groups, we conclude that these cell populations are in charge of immune response elicited by antimonial therapy. Interestingly, we also observed that NK cells were induced by LbAg to an exhaustion profile during all clinical stages of the disease. The increased antigen-specific activation and cytotoxic activity are in line with the strong inflammatory response described in this disease, a likely cause of tissue damage. These findings reinforce the involvement of these distinct cytotoxic-activated cell populations in the immunopathogenesis of CL, showing a character of specificity in this immune response.

Microbial Translocation Does Not Drive Immune Activation in Ugandan Children Infected With HIV

Objective

Immune activation is associated with morbidity and mortality during human immunodeficiency virus (HIV) infection, despite receipt of antiretroviral therapy (ART). We investigated whether microbial translocation drives immune activation in HIV-infected Ugandan children.

Methods

Nineteen markers of immune activation and inflammation were measured over 96 weeks in HIV-infected Ugandan children in the CHAPAS-3 Trial and HIV-uninfected age-matched controls. Microbial translocation was assessed using molecular techniques, including next-generation sequencing.

Results

Of 249 children included, 142 were infected with HIV; of these, 120 were ART naive, with a median age of 2.8 years (interquartile range [IQR], 1.7–4.0 years) and a median baseline CD4⁺ T-cell percentage of 20% (IQR, 14%–24%), and 22 were ART experienced, with a median age of 6.5 years (IQR, 5.9–9.2 years) and a median baseline CD4⁺ T-cell percentage of 35% (IQR, 31%–39%). The control group comprised 107 children without HIV infection. The median increase in the CD4⁺ T-cell percentage was 17 percentage points (IQR, 12–22 percentage points) at week 96 among ART-naive children, and the viral load was <100 copies/mL in 76% of ART-naive children and 91% of ART-experienced children. Immune activation decreased with ART use. Children could be divided on the basis of immune activation markers into the following 3 clusters: in cluster 1, the majority of children were HIV uninfected; cluster 2 comprised a mix of HIV-uninfected children and HIV-infected ART-naive or ART-experienced children; and in cluster 3, the majority were ART naive. Immune activation was low in cluster 1, decreased in cluster 3, and persisted in cluster 2. Blood microbial DNA levels were negative or very low across groups, with no difference between clusters except for Enterobacteriaceae organisms (the level was higher in cluster 1; P < .0001).

Conclusion

Immune activation decreased with ART use, with marker clustering indicating different activation patterns according to HIV and ART status. Levels of bacterial DNA in blood were low regardless of HIV status, ART status, and immune activation status. Microbial translocation did not drive immune activation in this setting.

Clinical Trials Registration

ISRCTN69078957.

Increased monocyte activation with age among HIV-infected long term non-progressor children: implications for early treatment initiation

OBJECTIVES

The key to newer therapeutic and eradication approaches often lies in understanding slow disease progression in HIV infection. The paediatric population has been poorly studied in this regard. We aimed to describe a cohort of perinatally infected long-term nonprogressor (LTNP) children living with HIV in India and to evaluate the immune biomarkers of disease progression.

METHODS

LTNPs (ART-naïve, with a CD4 count ≥ 500 cells/μL at age ≥ 7 years) among the cohort of HIV-infected children were identified and monitored longitudinally, and their CD4 T-cell counts and plasma viral loads were measured every 6 months. The plasma monocyte/macrophage activation markers, namely soluble CD14 (sCD14), soluble CD163 (sCD163) and interferon-inducible protein-10 (IP-10) were measured by enzyme-linked immunosorbent assay (ELISA) in LTNPs and progressors. The Mann-Whitney U-test was used to compare the two groups and P values < 0.05 were considered statistically significant. Spearman's rank or Pearson's correlation coefficient (r) was calculated to determine the associations between variables.

RESULTS

Among 378 children living with HIV-1 surveyed in our cohort, 40 (10.6%) were LTNPs. Longitudinal analysis of the LTNP data showed that both CD4 count and viral load declined significantly with age (P < 0.0001 for both). Plasma sCD14 levels were significantly (P < 0.005) higher in progressors and sCD163 levels were significantly (P < 0.0001) higher in LTNPs.

CONCLUSIONS

The prevalence of LTNPs in our cohort of perinatally infected children living with HIV was 10.6%. We observed a trend for associations between the increasing sCD163 monocyte/macrophage activation marker levels, declining CD4 counts and the gradual loss of nonprogressor status with age in the LTNPs. These findings underscore the need for early antiretroviral therapy in those children with proven slow disease progression.

Circulating Senescent T Cells Are Linked to Systemic Inflammation and Lesion Size During Human Cutaneous Leishmaniasis

Leishmania (Viannia) braziliensis induces American tegumentary leishmaniasis that ranges in severity from the milder form, cutaneous (CL) to severe disseminated cutaneous leishmaniasis. Patients with CL develop a cell-mediated Th1 immune response accompanied by production of inflammatory cytokines, which contribute to parasite control and pathogenesis of disease. Here, we describe the accumulation of circulating T cells with multiple features of telomere dependent-senescence including elevated expression of CD57, KLRG-1, and γH2AX that have short telomeres and low hTERT expression during cutaneous L. braziliensis infection. This expanded population of T cells was found within the CD45RA⁺CD27^- (EMRA) subset and produced high levels of inflammatory cytokines, analogous to the senescence-associated secretory profile (SASP) that has been described in senescent non-lymphoid cells. There was a significant correlation between the accumulation of these cells and the extent of systemic inflammation, suggesting that they are involved in the inflammatory response in this disease. Furthermore, these cells expressed high level of the skin homing receptor CLA and there was a highly significant correlation between the number of these cells in the circulation and the size of the Leishmania-induced lesions in the skin. Collectively our results suggest that extensive activation during the early stages of leishmaniasis drives the senescence of T cells with the propensity to home to the skin. The senescence-related inflammatory cytokine secretion by these cells may control the infection but also contribute to the immunopathology in the disease.

Serum Levels of Soluble CD40 Ligand and Neopterin in HIV Coinfected Asymptomatic and Symptomatic Visceral Leishmaniasis Patients

Human Immunodeficiency Virus (HIV) co-infection drastically increases the risk of developing overt visceral leishmaniasis (VL). The asymptomatic Leishmania infection window constitutes an opportunity to identify those HIV patients at highest risk by defining early markers associated with disease susceptibility or resistance. As intracellular parasite killing is essential, we investigated whether serum markers of macrophage activation were notably affected in HIV patients with an asymptomatic Leishmania infection or overt visceral leishmaniasis disease. Serum levels of soluble CD40 ligand and neopterin were assessed in 24 active VL-HIV patients, 35 HIV patients with asymptomatic Leishmania infection and 35 HIV endemic controls. All patients were recruited in L. donovani endemic regions of North-West Ethiopia. The serum levels of sCD40L and neopterin significantly decreased and increased in HIV patients with active VL compared to HIV patients with asymptomatic Leishmania infection, respectively. No statistically significant differences could be detected in neopterin and sCD40L levels between Leishmania asymptomatically infected HIV patients and endemic HIV control patients. However, an inverse trend, between Leishmania antibody positivity or VL development and neopterin levels could be seen. The CD4+ T-cell count was inversely correlated with serum neopterin levels, but not with sCD40L levels. Our results in HIV coinfected patients, correspond with the postulated protective role of sCD40L in VL and underline the importance of the CD40-CD40L pathway in resistance against the parasite. Neopterin levels suggest an increased macrophage activation upon infection and could have a value in clinical algorithms to, although non-specifically, improve prediction of VL development in HIV patients with asymptomatic Leishmania infection.

Visceral Leishmaniasis in Hospitalized HIV-Infected Patients in Pernambuco, Brazil

Common in four continents, visceral leishmaniasis (VL) is an important but neglected disease. Human immunodeficiency virus (HIV) infection increases the risk of developing VL in people from leishmaniasis-endemic areas, with worse prognosis when there is coinfection. We conducted a cross-sectional study to determine the prevalence of HIV/VL coinfection in patients admitted in three referral hospitals for HIV/acquired immunodeficiency syndrome (AIDS) in Pernambuco, Brazil, and to compare epidemiological, clinical, and laboratory characteristics among HIV/VL coinfected and HIV mono-infected individuals. The sample consisted of HIV patients aged 18 years or more, in a period of data collection of 6 months. We performed four Leishmania tests-polymerase chain reaction (PCR), direct agglutination test, rK39, and latex agglutination test-and individuals with at least one positive test were considered coinfected. The HIV/VL coinfection prevalence we found was 16.9%. We observed large variation in prevalence according to the Leishmania test used, with low coincidence of positive tests. The most frequent symptoms found were weight loss (75.6%), fever (67.6%), and cough (55.3%). When we compared HIV/VL coinfected and HIV mono-infected groups we did not observe statistically significant differences. Low educational level (P = 0.004) and pallor (P = 0.009) were more frequent in the coinfected group. Serum albumin level was higher in coinfected individuals (P = 0.009). It is important to follow-up these individuals to understand the dynamics of VL in people living with HIV. New tests are necessary, ideally differentiating active from latent infection. Testing for VL in people with HIV is important and should be considered as part of the initial investigation in these individuals.

Visceral leishmaniasis and HIV coinfection: current perspectives

Visceral leishmaniasis (VL) is caused by Leishmania donovani and Leishmania infantum. The burden of VL is concentrated in tropical and subtropical areas; however, HIV infection has spread VL over a hyperendemic area. Several outcomes are observed as a result of VL–HIV coinfection. Impacts are observed in immunopathogenesis, clinical manifestation, diagnosis, and therapeutic response. Concerning clinical manifestation, typical and unusual manifestation has been observed during active VL in HIV-infected patient, as well as alteration in immunoresponse, inducing greater immunosuppression by low CD4 T-lymphocyte count or even by induction of immunoactivation, with cell senescence. Serological diagnosis of VL in the HIV-infected is poor, due to low humoral response, characterized by antibody production, so parasitological methods are more recommended. Another important and even more challenging point is the definition of the best therapeutic regimen for VL in HIV-coinfected patients, because in this population there is greater failure and consequently higher mortality. The challenge of better understanding immunopathogenesis in order to obtain more effective therapies is one of the crucial points to be developed. The combination of drugs and the use of secondary prophylaxis associated with highly active antiretroviral therapy may be the best tool for treatment of HIV coinfection. Some derivatives from natural sources have action against Leishmania; however, studies have been limited to in vitro evaluation, without clinical trials.

Adaptive NKG2C+CD57+ Natural Killer Cell and Tim-3 Expression During Viral Infections

Repetitive stimulation by persistent pathogens such as human cytomegalovirus (HCMV) or human immunodeficiency virus (HIV) induces the differentiation of natural killer (NK) cells. This maturation pathway is characterized by the acquisition of phenotypic markers, CD2, CD57, and NKG2C, and effector functions—a process regulated by Tim-3 and orchestrated by a complex network of transcriptional factors, involving T-bet, Eomes, Zeb2, promyelocytic leukemia zinc finger protein, and Foxo3. Here, we show that persistent immune activation during chronic viral co-infections (HCMV, hepatitis C virus, and HIV) interferes with the functional phenotype of NK cells by modulating the Tim-3 pathway; a decrease in Tim-3 expression combined with the acquisition of inhibitory receptors skewed NK cells toward an exhausted and cytotoxic phenotype in an inflammatory environment during chronic HIV infection. A better understanding of the mechanisms underlying NK cell differentiation could aid the identification of new immunological targets for checkpoint blockade therapies in a manner that is relevant to chronic infection and cancer.

Sexually transmitted infections and immune activation among HIV-infected but virally suppressed youth on antiretroviral therapy

BACKGROUND

Human immunodeficiency virus (HIV) infection is associated with chronic immune activation, and concurrent sexually transmitted infections (STIs) may increase immune activation.

OBJECTIVES

Because HIV-infected youth are at high risk of STIs and little is known about the impact of STIs on immune activation in HIV-infected youth, we conducted an exploratory study examining the association between STIs and systemic inflammation and immune activation among HIV-infected adolescents.

STUDY DESIGN

Forty-nine behaviorally infected U.S. youth ages 18-24 years with baseline CD4⁺ T-cells >350 who maintained viral suppression on therapy by week 48 were included. Evaluation for STIs (herpes simplex virus [HSV], Chlamydia trachomatis, syphilis, Neisseria gonorrhoeae) was conducted as standard of care and reported on case report forms. Measures of T-cell subsets, systemic immune activation, and soluble factors were examined at week 48 for differences between participants with an STI diagnosis during the 48 weeks compared to those without an STI.

RESULTS

Forty-three participants (88%) were male; 57% had baseline CD4+ T-cell counts >500 cells/mm³. Eighteen youth were reported to have ≥1 STI. At week 48, participants with STIs demonstrated lower CD4⁺ T-cell counts (any STI vs. no STI, p = 0.024; HSV vs. no STI, p = 0.022) and evidence of increased systemic immune activation, including higher CD57 intensity, higher HLA-DR intensity, and lower CD28 percentage, when compared to those without STIs. There were no differences in soluble factors between STI groups.

CONCLUSIONS

Results indicate novel activation of CD4⁺ T-cells among HIV-infected youth who have STIs other than HSV, which may contribute to disease progression.

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.

Immune Activation and Bacterial Translocation: A Link between Impaired Immune Recovery and Frequent Visceral Leishmaniasis Relapses in HIV-Infected Patients

The maintenance of chronic immune activation due to leishmaniasis or even due to microbial translocation is associated with immunosenescence and may contribute to frequent relapses. Our aim was to investigate whether patients with HIV-associated visceral leishmaniasis (VL/HIV) who experience a single episode of VL have different immunological behaviors in comparison to those who experience frequent relapses. VL/HIV patients were allocated to non-relapsing (NR, n = 6) and relapsing (R, n = 11) groups and were followed from the active phase of VL up to 12 months post-treatment (mpt). The patients were receiving highly active antiretroviral therapy (HAART) and secondary prophylaxis after VL therapy. During active VL, the two groups were similar in all immunological parameters, including the parasite load. At 6 and 12 mpt, the NR group showed a significant gain of CD4⁺ T cells, a reduction of lymphocyte activation, and lower soluble CD14 and anti-Leishmania IgG3 levels compared to the R group. The viral load remained low, without correlation with the activation. The two groups showed elevated but similar percentages of senescent T cells. These findings suggest a decreased ability of the R group to downmodulate immune activation compared to the NR group. Such functional impairment of the effector response may be a useful indicator for predicting clinical prognosis and recommending starting or stopping secondary prophylaxis.

Relapse of visceral leishmaniasis in an HIV-infected patient successfully treated with a combination of miltefosine and amphotericin B

The present report documents a 49-year-old HIV-infected man receiving antiretroviral therapy with a suboptimal immune response and a CD4 count of 95 cells/mm(3), despite virological suppression. Investigation of bone marrow was conducted and yielded a diagnosis of visceral leishmaniasis. The clinical course was complicated by gastrointestinal involvment and relapse occurred after amphotericin B therapy. With the addition of miltefosine, the patient no longer presented with bone marrow amastigotes, and displayed an increased CD4 count and negative Leishmania polymerase chain reaction results. The present case highlights atypical presentation of visceral leishmaniasis, including poor immune reconstitution and gastrointestinal involvement. The high likelihood of relapse and response to combination therapy are illustrated.

Risk Factors for Death from Visceral Leishmaniasis in an Urban Area of Brazil

BACKGROUND

Over the last three decades, the epidemiological profile of visceral leishmaniasis (VL) has changed with epidemics occurring in large urban centers of Brazil, an increase in HIV/AIDS co-infection, and a significant increase in mortality. The objective of this study was to identify the risk factors associated with death among adult patients with VL from an urban endemic area of Brazil.

METHODOLOGY

A prospective cohort study included 134 adult patients with VL admitted to the University Hospital of the Federal University of Mato Grosso do Sul between August 2011 and August 2013.

PRINCIPAL FINDINGS

Patients ranged from 18 to 93 years old, with a mean age of 43.6 (±15.7%). Of these patients, 36.6% were co-infected with HIV/AIDS, and the mortality rate was 21.6%. In a multivariate analysis, the risk factors associated with death were secondary bacterial infection (42.86, 5.05-363.85), relapse (12.17, 2.06-71.99), edema (7.74, 1.33-45.05) and HIV/AIDS co-infection (7.33, 1.22-43.98).

CONCLUSIONS/SIGNIFICANCE

VL has a high mortality rate in adults from endemic urban areas, especially when coinciding with high rates of HIV/AIDS co-infection.