Delayed gastrointestinal-associated lymphoid tissue reconstitution in duodenum compared with rectum in HIV-infected patients initiating antiretroviral therapy.

BACKGROUND: We aimed to characterize the impact of antiretroviral therapy (ART) initiation on gastrointestinal-associated lymphoid tissue at various sites along the gastrointestinal site. METHODOLOGY: Peripheral blood and duodenal and rectal biopsies were obtained from 12 HIV to 33 treatment-naive HIV participants at baseline and after 9 months ART. Tissue was digested for immunophenotyping. Inflammatory, bacterial translocation and intestinal damage markers were measured in plasma. RESULTS: Twenty-six HIV patients completed follow-up. The lowest reconstitution of CD4 T cells and the lowest CD4/CD8 ratio during ART compared with blood were observed in the duodenum with the rectum being either intermediate or approaching blood levels. Regulatory T cells were in higher proportions in the duodenum than the rectum and neither declined significantly during ART. Several correlations with biomarkers of microbial translocation were observed including increases in lipoteichoic acid levels, which reflects Gram-positive bacterial translocation, correlated with increases in %CD4 T cells in the duodenum (Rho 0.773, P = 0.033), and with decreases in duodenal regulatory T-cell populations (Rho -0.40, P = 0.045). CONCLUSION: HIV-mediated immunological disruption is greater in the duodenum than rectum and blood before and during ART. Small intestine damage may represent a unique environment for T-cell depletion, which might be attenuated by interaction with Gram-positive bacteria.

Tissue Pharmacologic and Virologic Determinants of Duodenal and Rectal Gastrointestinal-Associated Lymphoid Tissue Immune Reconstitution in HIV-Infected Patients Initiating Antiretroviral Therapy.

Plasma, duodenal, and rectal tissue antiretroviral therapy (ART) drug concentrations, human immunodeficiency virus (HIV) RNA and HIV DNA copy numbers, and recovery of mucosal immunity were measured before and 9 months after initiation of 3 different ART regimens in 26 subjects. Plasma and tissue HIV RNA correlated at baseline and when 9-month declines were compared, suggesting that these compartments are tightly associated. Antiretroviral tissue:blood penetration ratios were above the 50% inhibitory concentration values in almost 100% of cases. There were no correlations between drug concentrations and HIV DNA/RNA. Importantly, no evidence was found for residual viral replication or deficient tissue drug penetration to account for delayed gastrointestinal-associated lymphoid tissue immune recovery.

Correction: Effects of Combined CCR5/Integrase Inhibitors-Based Regimen on Mucosal Immunity in HIV-Infected Patients Naïve to Antiretroviral Therapy: A Pilot Randomized Trial.

[This corrects the article DOI: 10.1371/journal.ppat.1005381.].

Effects of Combined CCR5/Integrase Inhibitors-Based Regimen on Mucosal Immunity in HIV-Infected Patients Naïve to Antiretroviral Therapy: A Pilot Randomized Trial.

Whether initiation of antiretroviral therapy (ART) regimens aimed at achieving greater concentrations within gut associated lymphoid tissue (GALT) impacts the level of mucosal immune reconstitution, inflammatory markers and the viral reservoir remains unknown. We included 12 HIV- controls and 32 ART-naïve HIV patients who were randomized to efavirenz, maraviroc or maraviroc+raltegravir, each with fixed-dose tenofovir disoproxil fumarate/emtricitabine. Rectal and duodenal biopsies were obtained at baseline and at 9 months of ART. We performed a comprehensive assay of T-cell subsets by flow cytometry, T-cell density in intestinal biopsies, plasma and tissue concentrations of antiretroviral drugs by high-performance liquid chromatography/mass spectroscopy, and plasma interleukin-6 (IL-6), lipoteichoic acid (LTA), soluble CD14 (sCD14) and zonulin-1 each measured by ELISA. Total cell-associated HIV DNA was measured in PBMC and rectal and duodenal mononuclear cells. Twenty-six HIV-infected patients completed the follow-up. In the duodenum, the quadruple regimen resulted in greater CD8+ T-cell density decline, greater normalization of mucosal CCR5+CD4+ T-cells and increase of the naïve/memory CD8+ T-cell ratio, and a greater decline of sCD14 levels and duodenal HIV DNA levels (P = 0.004 and P = 0.067, respectively), with no changes in HIV RNA in plasma or tissue. Maraviroc showed the highest drug distribution to the gut tissue, and duodenal concentrations correlated well with other T-cell markers in duodenum, i.e., the CD4/CD8 ratio, %CD4+ and %CD8+ HLA-DR+CD38+ T-cells. Maraviroc use elicited greater activation of the mucosal naïve CD8+ T-cell subset, ameliorated the distribution of the CD8+ T-cell maturational subsets and induced higher improvement of zonulin-1 levels. These data suggest that combined CCR5 and integrase inhibitor based combination therapy in ART treatment naïve patients might more effectively reconstitute duodenal immunity, decrease inflammatory markers and impact on HIV persistence by cell-dependent mechanisms, and show unique effects of MVC in duodenal immunity driven by higher drug tissue penetration and possibly by class-dependent effects.

Role of intestinal myofibroblasts in HIV-associated intestinal collagen deposition and immune reconstitution following combination antiretroviral therapy.

OBJECTIVE: To investigate the potential role of mucosal intestinal myofibroblasts (IMFs) in HIV and associated fibrosis in gut-associated lymphoid tissue. DESIGN: Profibrotic changes within the secondary lymphoid organs and mucosa have been implicated in failed immune reconstitution following effective combination antiretroviral therapy (cART). Microbial translocation is believed to be sustaining these systemic inflammatory pathways. IMFs are nonprofessional antigen-presenting cells with both immunoregulatory and mesenchymal functions that are ideally positioned to respond to translocating microbial antigen. METHODS: Duodenal biopsies, obtained from patients naive to cART, underwent trichrome staining and were examined for tissue growth factor-beta (TGF-ß) expression. Combined immunostaining and second harmonic generation analysis were used to determine IMF activation and collagen deposition. Confocal microscopy was performed to examine IMF activation and Toll-like receptor (TLR)4 expression. Finally, primary IMF cultures were stimulated with lipopolysaccharide to demonstrate the expression of the inflammatory biomarkers. RESULTS: The expression of the fibrosis-promoting molecule, TGF-ß1, is significantly increased in duodenal biopsies from HIV patients naïve to cART, and negatively correlated with subsequent peripheral CD4(+) recovery. The increase in TGF-ß1 coincided with an increase in collagen deposition in the duodenal mucosa in the tissue area adjacent to the IMFs. We also observed that IMFs expressed TLR4 and had an activated phenotype since they were positive for fibroblast activation protein. Finally, stimulation of IMFs from HIV patients with TLR4 resulted in significantly increased expression of profibrotic molecules, TGF-ß1, and interleukin-6. CONCLUSION: Our data support the hypothesis that activated IMFs may be among the major cells contributing to the profibrotic changes, and thus, the establishment and maintenance of systemic inflammation interfering with immune reconstitution in HIV patients.

Arcanobacterium haemolyticum osteomyelitis and sepsis: a diagnostic conundrum.

BACKGROUND: Arcanobacterium haemolyticum can cause severe systemic infections and sepsis. Thus, accurate and timely identification of the organism is essential. METHODS: Case report and review of the pertinent English-language literature. CASE REPORT: A 74-year-old male underwent repetitive surgical debridement and grafting for a full-thickness ulcer on the plantar surface of the left foot. One week after the last debridement, the patient presented to the emergency department with fever, hypotension, and severe left foot pain. A radiograph showed a soft-tissue defect of the plantar aspect of the left midfoot with gas along the lateral aspect of the fifth metatarsal. A below-knee amputation was performed. Blood culture and intraoperative tissue specimens grew colonies that exhibited ß-hemolysis on sheep blood agar and agglutinated with streptococcal B group antiserum. However, gram staining revealed that the organism was a gram-positive bacillus, and a reverse Christie, Atkins, Munch-Peterson (CAMP) test showed that the organism inhibited the ß-hemolysis of Staphylococcus aureus on sheep blood agar. Biochemical testing identified the organism as A. haemolyticum. CONCLUSIONS: It is important to investigate for A. haemolyticum when organisms with ß-hemolytic activity react with group B streptococcal antiserum. Otherwise, A. haemolyticum can be mis-identified as group B Streptococcus or Listeria monocytogenes. This distinction is important clinically, because despite good in vitro activity of penicillin (a first-line antibiotic for group B Streptococcus infections), treatment failures have been reported when penicillin has been used for A. haemolyticum infections.

Gastrointestinal-associated lymphoid tissue immune reconstitution in a randomized clinical trial of raltegravir versus non-nucleoside reverse transcriptase inhibitor-based regimens.

OBJECTIVES: To examine immune restoration in duodenal tissue and correlates of reduction of immune activation in chronic HIV-infected patients randomized to different treatment regimens. DESIGN: Randomized clinical trial (RCT) comparing raltegravir to a non-nucleoside reverse transcriptase inhibitor-based regimen, both with fixed-dose tenofovir difumerate/emtricitabine. METHODS: Antiretroviral therapy (ART)-naive volunteers underwent upper endoscopy for duodenal biopsies before and after 9 months of therapy. Tissue was paraffin-embedded for immunohistochemistry or digested into single-cell suspensions for flow cytometry of lymphocyte subsets and activation phenotype. Plasma-soluble CD14 levels were measured as a surrogate for bacterial translocation. RESULTS: Sixteen HIV-positive and seven control individuals completed study procedures. Small increases in duodenal lamina propria CD4 T-cell numbers were observed, especially when viewed relative to populations in control volunteers, with no differences between treatment arms. The increase in CD4 T-cell percentage was due largely to declines in CD8 T-cell numbers, which were disproportionately increased compared to peripheral blood and controls. Patients randomized to the raltegravir arm had consistent declines in both sCD14 levels and CD8 T-cell numbers in the duodenal tissue lamina propria. CONCLUSIONS: This first RCT of lymphocyte population restoration in duodenal tissue demonstrates more modest increases in CD4 T-cell numbers during the first 9 months of therapy than when considering CD3/CD4 percentages only. Although reduced after 9 months of ART, disproportional increased CD8 populations persist in duodenal gastrointestinal-associated lymphoid tissue (GALT). Local rather than systemic antigenic stimulation appears to be driving expanded CD8 T lymphocytes in GALT. Factors other than viral-induced CD8 expansion may be contributing to this local immunologic response.

Standardized comparison of the relative impacts of HIV-1 reverse transcriptase (RT) mutations on nucleoside RT inhibitor susceptibility.

Determining the phenotypic impacts of reverse transcriptase (RT) mutations on individual nucleoside RT inhibitors (NRTIs) has remained a statistical challenge because clinical NRTI-resistant HIV-1 isolates usually contain multiple mutations, often in complex patterns, complicating the task of determining the relative contribution of each mutation to HIV drug resistance. Furthermore, the NRTIs have highly variable dynamic susceptibility ranges, making it difficult to determine the relative effect of an RT mutation on susceptibility to different NRTIs. In this study, we analyzed 1,273 genotyped HIV-1 isolates for which phenotypic results were obtained using the PhenoSense assay (Monogram, South San Francisco, CA). We used a parsimonious feature selection algorithm, LASSO, to assess the possible contributions of 177 mutations that occurred in 10 or more isolates in our data set. We then used least-squares regression to quantify the impact of each LASSO-selected mutation on each NRTI. Our study provides a comprehensive view of the most common NRTI resistance mutations. Because our results were standardized, the study provides the first analysis that quantifies the relative phenotypic effects of NRTI resistance mutations on each of the NRTIs. In addition, the study contains new findings on the relative impacts of thymidine analog mutations (TAMs) on susceptibility to abacavir and tenofovir; the impacts of several known but incompletely characterized mutations, including E40F, V75T, Y115F, and K219R; and a tentative role in reduced NRTI susceptibility for K64H, a novel NRTI resistance mutation.

Lessons from maraviroc clinical trials.

Evaluation of: Gulick RM, Lalezari J, Goodrich J et al. Maraviroc for previously treated patients with R5 HIV-1 infection. N. Engl. J. Med. 359, 1429-1441 (2008). Maraviroc is the first commercially available HIV chemokine receptor antagonist targeting HIV that utilizes the CCR5 chemokine receptor (R5 tropic). The Maraviroc versus Optimized Therapy in Viremic Antiretroviral Treatment-Experienced Patients (MOTIVATE) trials were two randomized, placebo-controlled studies designed to demonstrate the activity of maraviroc in triple-class-experienced HIV individuals, with a primary end point of viral load suppression at 48 weeks. Maraviroc outperformed the placebo plus optimized background (OBT) arm, and exhibited a favorable safety profile with low discontinuation rates, which equaled those of the placebo plus OBT group. The results of these trials led to maraviroc receiving regulatory approval for the treatment of HIV.

Molecular characterization of stool microbiota in HIV-infected subjects by panbacterial and order-level 16S ribosomal DNA (rDNA) quantification and correlations with immune activation.

BACKGROUND: The relationship between gut microbial community composition at the higher-taxonomic order level and local and systemic immunologic abnormalities in HIV disease may provide insight into how bacterial translocation impacts HIV disease. METHODS: Antiretroviral-naive patients with HIV underwent upper endoscopy before and 9 months after starting antiretroviral treatment. Duodenal tissue was paraffin-embedded for immunohistochemical analysis and digested for fluorescence activated cell sorting for T-cell subsets and immune activation (CD38+/HLA-DR+) enumeration. Stool samples were provided from patients and control subjects for comparison. Metagenomic microbial DNA was extracted from feces for optimized 16S ribosomal RNA gene (rDNA) real-time quantitative polymerase chain reaction assays designed to quantify panbacterial loads and the relative abundances of proinflammatory Enterobacteriales order and the dominant Bacteroidales and Clostridiales orders. RESULTS: Samples from 10 HIV subjects before initiating and from six subjects receiving antiretroviral treatment were available for analysis. There was a trend for a greater proportion of Enterobacteriales in HIV-positive subjects compared with control subjects (P = 0.099). There were significant negative correlations between total bacterial load and duodenal CD4 and CD8 T-cell activation levels (r = -0.74, P = 0.004 and r = -0.67, P = 0.013, respectively). The proportions of Enterobacteriales and Bacteroidales were significantly correlated with duodenal CD4 T-cell depletion and peripheral CD8 T-cell activation, respectively. CONCLUSIONS: These data represent the first report of quantitative molecular and cellular correlations between total/universal and order-level gut bacterial populations and gastrointestinal-associated lymphoid tissue levels of immune activation in HIV-infected subjects. The correlations between lower overall 16S rDNA levels and tissue immune activation suggest that the gut microbiome may contribute to immune activation and influence HIV progression.