Immune recovery in acute and chronic HIV infection and the impact of thymic stromal lymphopoietin

Thymic stromal lymphopoietin participates in the host response to intra-amniotic inflammation leading to preterm labor and birth

The aim of this study was to establish the role of thymic stromal lymphopoietin (TSLP) in the intra-amniotic host response of women with spontaneous preterm labor (sPTL) and birth. Amniotic fluid and chorioamniotic membranes (CAM) were collected from women with sPTL who delivered at term (n = 30) or preterm without intra-amniotic inflammation (n = 34), with sterile intra-amniotic inflammation (SIAI, n = 27), or with intra-amniotic infection (IAI, n = 17). Amnion epithelial cells (AEC), Ureaplasma parvum, and Sneathia spp. were also utilized. The expression of TSLP, TSLPR, and IL-7Rα was evaluated in amniotic fluid or CAM by RT-qPCR and/or immunoassays. AEC co-cultured with Ureaplasma parvum or Sneathia spp. were evaluated for TSLP expression by immunofluorescence and/or RT-qPCR. Our data show that TSLP was elevated in amniotic fluid of women with SIAI or IAI and expressed by the CAM. TSLPR and IL-7Rα had detectable gene and protein expression in the CAM; yet, CRLF2 was specifically elevated with IAI. While TSLP localized to all layers of the CAM and increased with SIAI or IAI, TSLPR and IL-7Rα were minimal and became most apparent with IAI. Co-culture experiments indicated that Ureaplasma parvum and Sneathia spp. differentially upregulated TSLP expression in AEC. Together, these findings indicate that TSLP is a central component of the intra-amniotic host response during sPTL.

Evaluation of Clinical Biomarkers Related to CD4 Recovery in HIV-Infected Patients—5-Year Observation

Human Immunodeficiency Virus infection leads to the impairment of immune system function. Even long-term antiretroviral therapy uncommonly leads to the normalization of CD4 count and CD4:CD8 ratio. The aim of this study was to evaluate possible clinical biomarkers which may be related to CD4 and CD4:CD8 ratio recovery among HIV-infected patients with long-term antiretroviral therapy. The study included 68 HIV-infected patients undergoing sustained antiretroviral treatment for a minimum of 5 years. Clinical biomarkers such as age, gender, advancement of HIV infection, coinfections, comorbidities and applied ART regimens were analyzed in relation to the rates of CD4 and CD4:CD8 increase and normalization rates. The results showed that higher rates of CD4 normalization are associated with younger age (p = 0.034), higher CD4 count (p = 0.034) and starting the therapy during acute HIV infection (p = 0.012). Higher rates of CD4:CD8 ratio normalization are correlated with higher CD4 cell count (p = 0.022), high HIV viral load (p = 0.006) and acute HIV infection (p = 0.013). We did not observe statistically significant differences in CD4 recovery depending on gender, HCV/HBV coinfections, comorbidities and opportunistic infections. The obtained results advocate for current recommendations of introducing antiretroviral therapy as soon as possible, preferably during acute HIV infection, since it increases the chances of sufficient immune reconstruction.

Association of Eosinophilic Esophagitis and Human Immunodeficiency Virus

BACKGROUND

Eosinophilic esophagitis (EoE) is thought to be an atopic disorder causing dysphagia. HIV patients have dysphagia from both common (reflux esophagitis) and uncommon causes (idiopathic esophageal ulceration). Only a single case report about the occurrence of EoE in an HIV patient exists in literature.

AIM

The aim of this study was to determine if HIV and EoE occur concurrently using a large inpatient database.

METHODS

Data on hospital admissions of all HIV adult patients were extracted from the 2002-2014 National Inpatient Sample. Comorbidities and outcomes of interest were defined by querying all diagnostic and procedural fields for the corresponding ICD-9 codes. Univariable and multivariable logistic regression analysis was performed to assess the association between HIV and EoE. Similarly, we assessed the relation between HIV and eosinophilic gastroenteritis (EGE).

RESULTS

The total population comprised of 101,137,145 patients, of which 231,691 (0.229%) have HIV and 5038 (0.004%) have EoE. HIV patients were younger (45.2 vs 48 years old and more likely to be male (62.2% vs 41.5%) and African American (53.9% vs 14.2%) compared to non-HIV patients (P < 0.001 for all). After adjusting for potential cofounding factors, HIV patients had a statistically significant higher rate of EoE (Odds Ratio 2.108, with 95% confidence interval 1.268-3.506, P = 0.004) compared to the non-HIV group. On the other hand, HIV was not associated with increased risk of EGE (Odds Ratio 0.78, 95% confidence interval 0.109-5.557, P = 0.804).

CONCLUSION

Patients with HIV are twice as likely to have EoE compared to those without HIV. Evaluation of dysphagia in HIV patients should include assessment for EoE, especially when empiric antifungal therapy for candida esophagitis does not improve clinical symptoms.

Reduction in terminally differentiated T cells in virologically controlled HIV-infected aging patients on long-term antiretroviral therapy

Several studies have shown an increased accumulation of terminally differentiated T cells during HIV infection, suggestive of exhaustion/senescence, causing dysregulation of T cell homeostasis and function and rapid HIV disease progression. We have investigated whether long-term antiretroviral therapy (ART), which controls viremia and restores CD4 T cell counts, is correlated with reduction in terminally differentiated T cells, improved ratios of naïve to memory and function of T cells in 100 virologically controlled HIV-infected patients. We show that while the median frequencies of terminally differentiated CD4⁺ and CD8⁺ T cells (CD28^-, CD27^-, CD57⁺ and CD28^-CD57⁺), were higher in the virologically controlled HIV-infected patients’ cohort compared with uninfected individuals’ cohort, the frequencies of these cells significantly decreased with increasing CD4 T cell counts in HIV-infected patients. Although, the naïve CD4⁺ and CD8⁺ T cells were lower in HIV patients’ cohort than uninfected cohort, there was a significant increase in both naïve CD4⁺ and CD8⁺ T cells with increasing CD4 T cell counts in HIV-infected patients. The underlying mechanism behind this increased naïve CD4⁺ and CD8⁺ T cells in HIV-infected patients was due to an increase in recent thymic emigrants, CD4⁺CD31⁺, as compared to CD4⁺CD31^-. The CD4⁺ T cells of HIV-infected patients produced cytokines, including IL-2, IL-10 and IFN-γ comparable to uninfected individuals. In conclusion, virologically controlled HIV-infected patients on long-term ART show a significant reduction in terminally differentiated T cells, suggestive of decreased exhaustion/senescence, and improvement in the ratios of naïve to memory and function of T cells.

Alteration of CCR6+CD95+CD4+ naïve T cells in HIV-1 infected patients: Implication for clinical practice

The profound deficiency of Th17 cells contributes to HIV disease progression. The mechanisms of their perturbation remain unclear. Recently, CCR6⁺CD95⁺CD4⁺ naïve T cells (CCR6⁺CD95⁺CD4⁺ T_NA), identified as pre-committed Th17 precursors, were recognized as a subpopulation of CD4⁺ T cells with stem cell properties. Following phenotypical identification, we evaluated their level in patients during chronic HIV infection and following antiretroviral therapy (ART) using flow cytometry. The levels of CCR6⁺CD95⁺CD4⁺ T_NA were decreased during chronic HIV infection and correlated with CD4⁺ T cell counts. Immunological responders harbored higher frequency of CCR6⁺CD95⁺CD4⁺ T_NA, which was associated with CD4/CD8 T cell ratio. Immunological non-responders with lower frequency of CCR6⁺CD95⁺CD4⁺ T_NA failed to exhibit a correlation between CCR6⁺CD95⁺CD4⁺ T_NA and CCR6⁺CD95⁺CD4⁺ T_CM, and displayed elevated ratio of CCR6⁺CD95⁺CD4⁺ T_CM/T_NA. The number of CCR6⁺CD95⁺CD4⁺ T_NA was increased following early ART. These findings shed light on the importance of targeting pre-committed Th17 precursors that enhance immune reconstitution.

Tryptophan catabolism and immune activation in primary and chronic HIV infection

BACKGROUND

Kynurenine/Tryptophan ratio (KTR) is increased in HIV infection, and linked to immune activation. We hypothesized that early cART initiation results in lower KTR compared to late initiation. Furthermore, we hypothesized that KTR prior to cART is a predictor of the magnitude of subsequent reduction in immune activation.

METHODS

Prospective study including 57 HIV-infected individuals (primary HIV infection (N = 14), early presenters (>350 CD4+ T cells/μL, N = 24), late presenters (<200 CD4+ T cells/μL, N = 19)). Kynurenine and tryptophan were analysed by liquid chromatography-tandem mass spectrometry. Total CD4+ and CD8+ T cells were determined and proportion of activated CD38 + HLA-DR+ Tcells was measured using flow cytometry at baseline and after 6 and 12 months of cART.

RESULTS

At baseline, primary HIV infection had higher KTR than early presenters. However, similar KTR in primary HIV infection and early presenters was found after cART initiation, while late presenters had higher KTR at all time points. In primary HIV infection and early presenters, KTR was positively associated with proportion of activated cells at baseline. Furthermore, in early presenters the KTR at baseline was associated with proportion of activated cells after 6 and 12 months. Interestingly, in primary HIV infection the KTR at baseline was positively associated with reduction in proportion of CD8 + CD38 + HLA-DR T cells after 6 and 12 months.

CONCLUSIONS

Lower kynurenine/tryptophan ratio during follow-up was found after early initiation of cART. KTR in primary HIV infection and early presenters was positively associated with immune activation. Importantly, KTR in primary HIV infection predicted the magnitude of subsequent reduction in immune activation. Thus, a beneficial effect of early cART on KTR was suggested.