Peripheral blood cell-specific cytokines in persons with untreated HIV infection in Malawi, Africa

Infection with HIV-1 subtype D among acutely infected Ugandans is associated with higher median concentration of cytokines compared to subtype A

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HIV-1 subtype D exhibited significantly higher median concentrations of cytokines

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IL-12/23p40 and IL-1α were associated with faster CD4⁺T cell count decline

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bFGF was associated with maintenance of CD4+ counts above 350 cells/microliter

Objective

The observation that HIV-1 subtype D progresses faster to disease than subtype A prompted us to examine cytokine levels early after infection within the predominant viral subtypes that circulate in Uganda and address the following research questions: (1) Do cytokine levels vary between subtypes A1 and D? (2) Do cytokine profiles correlate with disease outcomes?

Methods

To address these questions, HIV-1 subtypes were determined by population sequencing of the HIV-1 pol gene and 37 plasma cytokine concentrations were evaluated using V-Plex kits on Meso Scale Discovery platform in 65 recent sero-converters.

Results

HIV-1 subtype D (pol) infections exhibited significantly higher median plasma concentrations of IL-5, IL-16, IL-1α, IL-7, IL-17A, CCL11 (Eotaxin-1), CXCL10 (IP-10), CCL13 (MCP-4) and VEGF-D compared to subtype A1 (pol) infections. We also found that IL-12/23p40 and IL-1α were associated with faster CD4⁺T cell count decline, while bFGF was associated with maintenance of CD4+ counts above 350 cells/microliter.

Conclusion

Our results suggest that increased production of cytokines in early HIV infection may trigger a disruption of the immune environment and contribute to pathogenic mechanisms underlying the accelerated disease progression seen in individuals infected with HIV-1 subtype D in Uganda.

Plasma Cytokine Levels in Chronic Asymptomatic HIV-1 Subtype C Infection as an Indicator of Disease Progression in Botswana: A Retrospective Case Control Study

HIV infects cells of the immune system causing immune activation and proliferation of immune cells, leading to alteration of production and activity of a number of cytokines. These changes in cytokine levels can affect the immune function, and have the potential to directly impact the course of HIV disease. We characterized plasma cytokine concentration profiles in HIV-1 subtype C chronically infected, antiretroviral therapy (ART)-naive participants to establish their influence on disease progression and viremia. Plasma levels of interleukin (IL)-1α, IL-7, IL-12p40, granulocyte macrophage-colony-stimulating factor (GM-CSF), and interferon (IFN)-γ were quantified in samples from 60 treatment-naive participants in the placebo arm of the completed Micronutrient-HIV disease progressions study, "Dikotlana" (2004-2009) in Gaborone, Botswana. Participants were stratified into progressors (P) and nonprogressors (NP) based on their rates of CD4(+) T cell depletion during the study period. Nonprogressors were those who had <1% CD4(+) T cell depletion at 24 months postenrollment. Progressors were defined as those with CD4(+) T cell depletion of >15% at 24 months postenrollment. Cytokine levels were compared between P and NP using the Mann-Whitney U-test. Logistic regression analysis was used to determine if cytokines predicted disease progression. Correlations of cytokines with CD4(+) T cell counts and viral loads were determined by the Spearman rank test. Median baseline CD4(+) T cell counts were 453 (Q1, Q3; 401, 592) and 479 (Q1, Q3; 401-592) for nonprogressors and progressors, respectively. Nonprogressors had a higher viral set point than progressors. IL-12p40 levels were significantly higher in the P than in NP at enrollment and 24 months (p < 0.05). Levels of IL-1α, IL-7, IFN-γ, and GM-CSF did not differ significantly between the two groups. Except for IL-12p40, which displayed an inverse correlation with CD4(+) T cell counts and a direct correlation with viral load, all other cytokines showed no correlations. IL-12p40 was found to be the most significant predictor of progression and its production was most likely driven by HIV replication products as evidenced by its direct correlation with viral load. In chronic HIV-1 subtype C infection, CD4(+) T cell counts and plasma cytokine levels may not necessarily evolve in parallel, suggesting the involvement of other factors in determining the rates of CD4(+) T cell depletion.

Targeting Tuberculosis and HIV Infection-Specific Regulatory T Cells with MEK/ERK Signaling Pathway Inhibitors

Human regulatory T cells (Tregs) are essential in maintaining immunological tolerance and suppress effector T cells. Tregs are commonly up-regulated in chronic infectious diseases such as tuberculosis (TB) and human immunodeficiency virus (HIV) infection and thereby hamper disease-specific immune responses and eradication of pathogens. The MEK/ERK signaling pathway is involved in regulation of the FoxP3 transcription factor, which directs a lineage-specific transcriptional program to define Tregs and control their suppressive function. Here, we aimed to target activation of disease-specific Tregs by inhibition of the MEK/ERK signaling pathway based on the hypothesis that this would improve anti-HIV and anti-TB immunity. Stimulation of T cells from untreated TB (n = 12) and HIV (n = 8) patients with disease-specific antigens in vitro in the presence of the MEK inhibitor (MEKI) trametinib (GSK1120212) resulted in significant down-regulation of both FoxP3 levels (MFI) and fractions of resting (CD45RA⁺FoxP3⁺) and activated (CD45RA⁻FoxP3⁺⁺) Tregs. MEKI also reduced the levels of specific T effector cells expressing the pro-inflammatory cytokines (IFN-γ, TNF-α and IL-2) in both HIV and TB patients. In conclusion, MEKIs modulate disease antigen-specific Treg activation and may have potential application in new treatment strategies in chronic infectious diseases where reduction of Treg activity would be favorable. Whether MEKIs can be used in current HIV or TB therapy regimens needs to be further investigated.

Microbial translocation, the innate cytokine response, and HIV-1 disease progression in Africa

Reports from the United States have demonstrated that elevated markers of microbial translocation from the gut may be found in chronic and advanced HIV-1 infection and are associated with an increase in immune activation. However, this phenomenon's role in HIV-1 disease in Africa is unknown. This study examined the longitudinal relationship between microbial translocation and circulating inflammatory cytokine responses in a cohort of people with varying rates of HIV-1 disease progression in Rakai, Uganda. Multiple markers for microbial translocation (lipopolysaccharide, endotoxin antibody, and sCD14) did not change significantly during HIV-1 disease progression. Moreover, circulating immunoreactive cytokine levels either decreased or remained virtually unchanged throughout disease progression. These data suggest that microbial translocation and its subsequent inflammatory immune response do not have a causal relationship with HIV-1 disease progression in Africa.

Human aflatoxicosis in developing countries: a review of toxicology, exposure, potential health consequences, and interventions

Aflatoxins are well recognized as a cause of liver cancer, but they have additional important toxic effects. In farm and laboratory animals, chronic exposure to aflatoxins compromises immunity and interferes with protein metabolism and multiple micronutrients that are critical to health. These effects have not been widely studied in humans, but the available information indicates that at least some of the effects observed in animals also occur in humans. The prevalence and level of human exposure to aflatoxins on a global scale have been reviewed, and the resulting conclusion was that approximately 4.5 billion persons living in developing countries are chronically exposed to largely uncontrolled amounts of the toxin. A limited amount of information shows that, at least in those locations where it has been studied, the existing aflatoxin exposure results in changes in nutrition and immunity. The aflatoxin exposure and the toxic affects of aflatoxins on immunity and nutrition combine to negatively affect health factors (including HIV infection) that account for >40% of the burden of disease in developing countries where a short lifespan is prevalent. Food systems and economics render developed-country approaches to the management of aflatoxins impractical in developing-country settings, but the strategy of using food additives to protect farm animals from the toxin may also provide effective and economical new approaches to protecting human populations.

T-cell depletion and immunity to malaria in HIV-infections

Although early reports on HIV and malaria in co-infected subjects indicated little apparent interaction between the two infections, more recent investigations have found evidence for HIV increasing the risk from malaria. Conversely, increased viral load in susceptible cells occurs in malaria-infected people. However, the overall pattern of results is still somewhat confusing and contradictory. While morbidity from malaria may be greater in HIV-positive patients and in several reports the mortality risk is also higher, major increases in blood-stage parasitaemias that one might expect are not generally observed. The results of surveys are summarized and discussed in the context of what is known of malaria and HIV immunology in the light of recent data from humans as well as animal models.