Visceral leishmaniasis in Northeast Brazil: What is the impact of HIV on this protozoan infection?

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

BACKGROUND

Leishmania infantum can be an opportunistic pathogen, with an immunocompromised status increasing the risk of converting asymptomatic infection to symptomatic visceral leishmaniasis (VL). VL has approximately 5% fatality rate; and HIV coinfection (AIDS/VL) increases this risk. We hypothesized that, relative to those with HIV alone, people with co-infection would have altered T cell activation which could impact on the risk of VL.

METHODS

A cross-sectional study was performed between 2014 and 2016 to determine the prevalence of L. infantum infection in people living with HIV (PLHIV) residing in Brazil (n = 1,372). Subsequent incident cases of VL were ascertained from a public health database through 2018 and from a cohort of families with VL. Immune status of 69 participants was evaluated and comparisons made between those with and without HIV, with latent or with active Leishmania infection and those without HIV but with active or resolved Leishmania or T cell hypersensitivity to Leishmania antigen and healthy control subjects.

RESULTS

A total of 24.2% of PLHIV had positive anti-IgG L. infantum antibodies. The relative risk of developing AIDS/VL was 2.27 (95% CI: 0.920 to 5.59; p = 0.07) to HIV/Leish coinfected subjects with positive leishmania serology compared to HIV subjects without leishmania serology. Poor adherence to antiretroviral therapy (p = 0.0008) or prior opportunistic infections (p = 0.0007) was associated with development of AIDS/VL in asymptomatic HIV/Leish. CD4+ and CD8+ T cells counts or viral load 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. Likewise, senescent (CD57+) and PD1+ CD8+ T cells were higher in asymptomatic HIV/Leish than in AIDS/VL or HIV groups.

CONCLUSION

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

High seroprevalence of Leishmania infantum is linked to immune activation in people with HIV: a two-stage cross-sectional study in Bahia, Brazil

Visceral leishmaniasis is an opportunistic disease in HIV-1 infected individuals, unrecognized as a determining factor for AIDS diagnosis. The growing geographical overlap of HIV-1 and Leishmania infections is an emerging challenge worldwide, as co-infection increases morbidity and mortality for both infections. Here, we determined the prevalence of people living with HIV (PWH) with a previous or ongoing infection by Leishmania infantum and investigated the virological and immunological factors associated with co-infection. We adopted a two-stage cross-sectional cohort (CSC) design (CSC-I, n = 5,346 and CSC-II, n = 317) of treatment-naïve HIV-1-infected individuals in Bahia, Brazil. In CSC-I, samples collected between 1998 and 2013 were used for serological screening for leishmaniasis by an in-house Enzyme-Linked Immunosorbent Assay (ELISA) with SLA (Soluble Leishmania infantum Antigen), resulting in a prevalence of previous or ongoing infection of 16.27%. Next, 317 PWH were prospectively recruited from July 2014 to December 2015 with the collection of sociodemographic and clinical data. Serological validation by two different immunoassays confirmed a prevalence of 15.46 and 8.20% by anti-SLA, and anti-HSP70 serology, respectively, whereas 4.73% were double-positive (DP). Stratification of these 317 individuals in DP and double-negative (DN) revealed a significant reduction of CD4+ counts and CD4+/CD8+ ratios and a tendency of increased viral load in the DP group, as compared to DN. No statistical differences in HIV-1 subtype distribution were observed between the two groups. However, we found a significant increase of CXCL10 (p = 0.0076) and a tendency of increased CXCL9 (p = 0.061) in individuals with DP serology, demonstrating intensified immune activation in this group. These findings were corroborated at the transcriptome level in independent Leishmania- and HIV-1-infected cohorts (Swiss HIV Cohort and Piaui Northeast Brazil Cohort), indicating that CXCL10 transcripts are shared by the IFN-dominated immune activation gene signatures of both pathogens and positively correlated to viral load in untreated PWH. This study demonstrated a high prevalence of PWH with L. infantum seropositivity in Bahia, Brazil, linked to IFN-mediated immune activation and a significant decrease in CD4+ levels. Our results highlight the urgent need to increase awareness and define public health strategies for the management and prevention of HIV-1 and L. infantum co-infection.

Visceral leishmaniasis and HIV coinfection in Brazil: epidemiological profile and spatial patterns

BACKGROUND

Geographical overlap of human visceral leishmaniasis (HVL) and HIV infection favors occurrences of HVL/HIV coinfection. The increasing numbers of cases of HVL/HIV coinfection are a worldwide concern and knowledge of the factors involved can help in developing preventive measures.

METHODS

We aimed to identify spatial patterns and describe the epidemiological profile of HVL/HIV coinfection in Brazil from 2007 to 2015. This was an ecological study, in which thematic maps were created through geoprocessing tools, based on secondary data obtained from open-access platforms, to identify priority areas for interventions for controlling HLV/HIV coinfection, using the TerraView 4.2.2 software.

RESULTS

We found spatial autocorrelations between the HVL/HIV rates of neighboring municipalities according to the global Moran index (0.10; p<0.01). The highest HVL/HIV rate was in the central-western region. Among the epidemiological characteristics according to the regions, an increasing trend in the annual variation rate was observed, with positive values over the years and statistical significance (p<0.05) in the North with 1.62 (95% CI 0.57 to 2.69; p=0.02) and Northeast with 6.41 (95% CI 2.60 to 10.37; p=0.006). Similarly, increasing trends were observed in the states of Maranhão with 21.34 (95% CI 13.99 to 9.16; p<0.001) and Sergipe with 5.44 (95% CI 0.61 to 10.50; p=0.04).

CONCLUSIONS

Our results showed spatial overlap between occurrences of HVL and HIV with spatial patterns of HVL/HIV coinfection, thus revealing that the numbers of cases reported are increasing. Identifying areas with higher coinfection indices contributes to applying interventions and control measures among targeted populations, to prevent new cases.

Factors associated with relapse and hospital death in patients coinfected with visceral leishmaniasis and HIV: a longitudinal study

OBJECTIVE

Visceral leishmaniasis (VL) is an endemic parasitic disease in Latin America, and its clinical picture is aggravated in coinfections with the human immunodeficiency virus (HIV). The objective of this study was to investigate clinical factors and laboratory variables associated with VL relapse and death in VL/HIV coinfected patients.

METHODS

A prospective longitudinal study was conducted from January 2013 to July 2020 among 169 patients coinfected with VL and HIV. The outcomes investigated were the occurrence of VL relapse and death. Chi-square test, Mann-Whitney test and logistic regression models were used for statistical analysis.

RESULTS

The occurrence rates were 41.4% for VL relapse and 11.2% for death. Splenomegaly and adenomegaly were associated with the increased risk of VL relapse. Patients with VL relapse had higher levels of urea (p = .005) and creatinine (p < .001). Patients who died had lower red blood cell counts (p = .012), hemoglobin (p = .017) and platelets (p < .001). The adjusted model showed that antiretroviral therapy for more than 6 months was associated with a decrease in VL relapse, and adenomegaly was associated with an increase in VL relapse. In addition, edema, dehydration, poor general health status, and paleness were associated with an increase in hospital death.

CONCLUSION

The findings suggest that adenomegaly, antiretroviral therapy, and renal abnormalities can be associated with VL relapse, while hematological abnormalities, and clinical manifestations like paleness, and edema can be associated with an increased odds of hospital death.

TRIAL REGISTRATION NUMBER

The study was submitted to the Ethics and Research Committee of the Federal University of Maranhão (Protocol: 409.351).

Parasite Genotype Is a Major Predictor of Mortality from Visceral Leishmaniasis

Visceral leishmaniasis (VL) is a potentially fatal disease caused mainly by Leishmania infantum in South America and Leishmania donovani in Asia and Africa. Disease outcomes have been associated with patient genotype, nutrition, age, sex, comorbidities, and coinfections. In this study, we examine the effects of parasite genetic variation on VL disease severity in Brazil. We collected and sequenced the genomes of 109 L. infantum isolates from patients in northeastern Brazil and retrieved matching patient clinical data from medical records, including mortality, sex, HIV coinfection, and laboratory data (creatinine, hemoglobin, and leukocyte and platelet counts). We identified genetic differences between parasite isolates, including single nucleotide polymorphisms (SNPs), small insertions/deletions (indels), and variations in genic, intergenic, and chromosome copy numbers (copy number variants [CNVs]). To describe associations between the parasite genotypes and clinical outcomes, we applied quantitative genetics methods of heritability and genome-wide association studies (GWAS), treating clinical outcomes as traits that may be influenced by parasite genotype. Multiple aspects of the genetic analysis indicate that parasite genotype affects clinical outcomes. We estimate that parasite genotype explains 83% chance of mortality (narrow-sense heritability [h²] = 0.83 ± 0.17) and has a significant relationship with patient sex (h² = 0.60 ± 0.27). Impacts of parasite genotype on other clinical traits are lower (h² ≤ 0.34). GWAS analysis identified multiple parasite genetic loci that were significantly associated with clinical outcomes; 17 CNVs were significantly associated with mortality, two with creatinine, and one with bacterial coinfection, jaundice, and HIV coinfection, and two SNPs/indels and six CNVs were associated with age, jaundice, HIV and bacterial coinfections, creatinine, and/or bleeding sites. Parasite genotype is an important factor in VL disease severity in Brazil. Our analysis indicates that specific genetic differences between parasites act as virulence factors, enhancing risks of severe disease and mortality. More detailed understanding of these virulence factors could be exploited for novel therapies. IMPORTANCE Multiple factors contribute to the risk of mortality from visceral leishmaniasis (VL), including, patient genotype, comorbidities, and nutrition. Many of these factors are influenced by socioeconomic biases. Our work suggests that the virulence of the infecting parasite is an important risk factor for mortality. We pinpoint some specific genomic markers that are associated with mortality, which can lead to a greater understanding of the molecular mechanisms that cause severe VL disease, to the identification of genetic markers for virulent parasites, and to the development of drug and vaccine therapies.

Magnitude of visceral leishmaniasis and HIV coinfection and association with social determinants of health in the Northeast region of Brazil: a retrospective, spatiotemporal model (2010-2018)

The Northeast region of Brazil (NRB) includes the states with the highest prevalence of visceral leishmaniasis (VL), as well as those with significant increases in HIV cases. This study aims to analyze the spatiotemporal patterns of VL-HIV coinfection and its association with the social determinants of health (SDH) in the NRB. Time trend analysis and Bayesian spatial statistical inferences, Moran's autocorrelation, and retrospective space-time scanning were performed. Spatial regression modelling was used to build an explanatory model for the occurrence of VL-HIV coinfection within NRB. A total of 1550 cases of VL-HIV coinfection were confirmed. We observed a higher prevalence among males (1232; 83%), individuals aged from 20 to 59 years (850; 54.8%), non-white skin color (1,422; 91.7%), and with low education (550; 35.48%). NRB showed an increasing and significant trend in the detection rate of coinfection (APC, 5.3; 95% CI, 1.4 to 9.4). The states of Maranhão and Piauí comprised the high-risk cluster. The SDH that most correlated with the occurrence of coinfection were poor housing, low income, and low education. VL-HIV is dispersed in the NRB but chiefly affects states with greater social vulnerability. Taken together, these findings reinforce the necessity to implement surveillance strategies that will contribute to the reduction of cases in these populations.

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.