High seroprevalence of <i>Leishmania infantum</i> is linked to immune activation in people with HIV: a two-stage cross-sectional study in Bahia, Brazil
Bibliographic record
Abstract
ABSTRACT Background Visceral leishmaniasis is an opportunistic disease in HIV-1 infected individuals, although not yet recognized 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. Here, we determined the prevalence of people living with HIV (PWH) with a previous or ongoing infection by Leishmania infantum in Bahia, Brazil and investigated the virological and immunological factors associated with co-infection. Methodology and Principal Findings 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 at the time of HIV-1 diagnosis between 1998 and 2013 were used for serological screening for leishmaniasis by an in-house immunoassay (ELISA) with SLA (Soluble Leishmania 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 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/IP-10 ( p =0.0076) and a tendency of increased CXCL9/MIG ( p =0.061) in individuals with DP serology for L. infantum , 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. Conclusions/Significance 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. AUTHOR SUMMARY More than 1 billion people live in areas endemic for leishmaniasis and are at risk of infection, which includes one third of the 38 million people living with HIV (PWH) worldwide. Leishmaniasis is a neglected tropical disease caused by infection with Leishmania parasites, transmitted by bites from infected sand flies. HIV/ Leishmania co-infection is increasing worldwide, especially in Southern Europe and Brazil, due to both human and ecological factors (migration, climate change, deforestation). This study demonstrates that a worryingly high number (one out of 6) of PWH in Bahia (Northeast Brazil) show previous or ongoing infection with the parasite Leishmania infantum, determined by antibodies detection against this parasite in PWH. Using a rigorous study design with data collection over 18 years in >5500 PWH, we found similarly high numbers (16.3% and 15.5%) of PWH with antibodies against Leishmania infantum in two consecutive cohorts. Moreover, PWH with antibodies against Leishmania infantum in Bahia, Brazil displayed a worse immune profile, with lower CD4 immune cells numbers and immune activation mediated by interferon, which we confirmed in independent HIV- and Leishmania -infected cohorts from other geographic areas. Our results underscore the need to raise awareness and define public health strategies to prevent HIV/ Leishmania co-infection, since therapeutic failure and mortality are strongly increased in co-infected PWH, even with antiretroviral therapy as standard of care.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".