Massive CD8 T cell response to primary HIV infection in the setting of severe clinical presentation

Delayed differentiation of potent effector CD8+ T cells reducing viremia and reservoir seeding in acute HIV infection

CD8⁺ T cells play a critical role in controlling HIV viremia and could be important in reducing HIV-infected cells in approaches to eradicate HIV. The simian immunodeficiency virus model provided the proof of concept for a CD8⁺ T cell-mediated reservoir clearance but showed conflicting evidence on the role of these cells to eliminate HIV-infected cells. In humans, HIV-specific CD8⁺ T cell responses have not been associated with a reduction of the HIV-infected cell pool in vivo. We studied HIV-specific CD8⁺ T cells in the RV254 cohort of individuals initiating ART in the earliest stages of acute HIV infection (AHI). We showed that the HIV-specific CD8⁺ T cells generated as early as AHI stages 1 and 2 before peak viremia are delayed in expanding and acquiring effector functions but are endowed with higher memory potential. In contrast, the fully differentiated HIV-specific CD8⁺ T cells at peak viremia in AHI stage 3 were more prone to apoptosis but were associated with a steeper viral load decrease after ART initiation. Their capacity to persist in vivo after ART initiation correlated with a lower HIV DNA reservoir. These findings demonstrate that HIV-specific CD8⁺ T cell magnitude and differentiation are delayed in the earliest stages of infection. These results also demonstrate that potent HIV-specific CD8⁺ T cells contribute to the reduction of the pool of HIV-producing cells and the HIV reservoir seeding in vivo and provide the rationale to design interventions aiming at inducing these potent responses to cure HIV infection.

(1→3)-β-d-Glucan: A Biomarker for Microbial Translocation in Individuals with Acute or Early HIV Infection?

Background

The extent of gut microbial translocation, which plays roles in HIV disease progression and non-AIDS comorbidities, appears to vary with the composition of the gut microbiome, particularly the presence of Lactobacillales, which reduce mucosal injury. While low proportions of Lactobacillales in the distal gut microbiome are a very promising indicator of microbial translocation, measurement is expensive and complicated and not feasible for clinical routine. (1→3)-β-d-Glucan (BDG) is a component of most fungal cell walls and might be a surrogate marker for Lactobacillales proportion in the gut and a useful indicator of HIV-associated gut injury. This study evaluated BDG as a biomarker of gut integrity in adults with acute or early HIV infection (AEH).

Methods

Study samples were collected longitudinally during study visits at weeks 0, 12, and 24 in a cohort of 11 HIV-infected men starting antiretroviral therapy during AEH. Blood plasma levels of BDG, soluble cluster of differentiation 14 (sCD14) and lipopolysaccharide (LPS) were measured and then correlated with the proportion of Lactobacillales in the distal gut microbiome, as measured by 16s rDNA sequencing by using mixed-effects models with random intercepts.

Results

Mean BDG and sCD14 levels across subjects were associated with Lactobacillales after controlling for time effects and within-subjects correlations (p-values < 0.05), while LPS levels were not. Specifically, each point increase in mean BDG and sCD14 levels across participants was associated with 0.31 ± 0.14 and 0.03 ± 0.01 percent decrease in mean Lactobacillales proportions, respectively.

Conclusion

BDG and sCD14 may be indicators of low Lactobacillales in the gut in adults with acute or early HIV infection, and serve as biomarkers of gut integrity and microbial translocation in HIV infection. Larger studies are needed to confirm our findings.