Nicolas Noel

Elimination of HIV-1-infected cells by broadly neutralizing antibodies

The Fc region of HIV-1 Env-specific broadly neutralizing antibodies (bNAbs) is required for suppressing viraemia, through mechanisms which remain poorly understood. Here, we identify bNAbs that exert antibody-dependent cellular cytotoxicity (ADCC) in cell culture and kill HIV-1-infected lymphocytes through natural killer (NK) engagement. These antibodies target the CD4-binding site, the glycans/V3 and V1/V2 loops on gp120, or the gp41 moiety. The landscape of Env epitope exposure at the surface and the sensitivity of infected cells to ADCC vary considerably between viral strains. Efficient ADCC requires sustained cell surface binding of bNAbs to Env, and combining bNAbs allows a potent killing activity. Furthermore, reactivated infected cells from HIV-positive individuals expose heterogeneous Env epitope patterns, with levels that are often but not always sufficient to trigger killing by bNAbs. Our study delineates the parameters controlling ADCC activity of bNAbs, and supports the use of the most potent antibodies to clear the viral reservoir.

Adipose Tissue Is a Neglected Viral Reservoir and an Inflammatory Site during Chronic HIV and SIV Infection

Two of the crucial aspects of human immunodeficiency virus (HIV) infection are (i) viral persistence in reservoirs (precluding viral eradication) and (ii) chronic inflammation (directly associated with all-cause morbidities in antiretroviral therapy (ART)-controlled HIV-infected patients). The objective of the present study was to assess the potential involvement of adipose tissue in these two aspects. Adipose tissue is composed of adipocytes and the stromal vascular fraction (SVF); the latter comprises immune cells such as CD4+ T cells and macrophages (both of which are important target cells for HIV). The inflammatory potential of adipose tissue has been extensively described in the context of obesity. During HIV infection, the inflammatory profile of adipose tissue has been revealed by the occurrence of lipodystrophies (primarily related to ART). Data on the impact of HIV on the SVF (especially in individuals not receiving ART) are scarce. We first analyzed the impact of simian immunodeficiency virus (SIV) infection on abdominal subcutaneous and visceral adipose tissues in SIVmac251 infected macaques and found that both adipocytes and adipose tissue immune cells were affected. The adipocyte density was elevated, and adipose tissue immune cells presented enhanced immune activation and/or inflammatory profiles. We detected cell-associated SIV DNA and RNA in the SVF and in sorted CD4+ T cells and macrophages from adipose tissue. We demonstrated that SVF cells (including CD4+ T cells) are infected in ART-controlled HIV-infected patients. Importantly, the production of HIV RNA was detected by in situ hybridization, and after the in vitro reactivation of sorted CD4+ T cells from adipose tissue. We thus identified adipose tissue as a crucial cofactor in both viral persistence and chronic immune activation/inflammation during HIV infection. These observations open up new therapeutic strategies for limiting the size of the viral reservoir and decreasing low-grade chronic inflammation via the modulation of adipose tissue-related pathways.

Elevated IP10 levels are associated with immune activation and low CD4⁺ T-cell counts in HIV controller patients

Background:Although HIV controllers (HICs) achieve long-term control of viremia in the absence of antiretroviral therapy (ART), they display marked immune activation. The levels of inflammatory biomarkers in HICs and the biomarkers’ relationships with immunologic and virologic status have yet to be fully characterized. Design:A cohort study. Methods:Plasma levels of seven biomarkers [tumor necrosis factor (TNF)&agr;, interleukin (IL)6, IL10, interferon gamma-induced protein 10 (IP10), monocyte chemoattractant protein-1 (MCP1), soluble CD14 (sCD14), soluble CD163 (sCD163)] were compared in 70 HICs, 33 HIV-1-infected, treatment-naive noncontrollers (viremic patients), 30 ART-treated patients and 40 healthy donors. In HICs, we investigated the interplay between biomarkers, cell activation and the CD4+ T-cell count. Results:HICs had higher levels of IP10, TNF&agr; and sCD14 than healthy donors did (P < 0.01 for each). Also, TNF&agr; and sCD14 levels of the HICs were similar to those measured in viremic and ART-treated patients. However, the levels of IL6 and IL10 were significantly lower in HICs than in viremic or ART-treated patients. In HICs, only IP10 levels differed significantly from those in both healthy donors and viremic patients, and were positively correlated with the expression of CD8+ and CD4+ T-cell activation markers. The IP10 levels of HICs were still elevated 12 and 24 months after the initial assay. Lastly, IP10 levels at enrollment were negatively correlated with the CD4+ T-cell count at enrollment and 12 months later. Conclusion:HICs display a number of inflammatory features associated with persistent T-cell immune activation.

Safety and efficacy of oral direct inhibitors of thrombin and factor Xa in antiphospholipid syndrome.

BACKGROUND Long-term anticoagulation is recommended in antiphospholipid syndrome with thrombosis in order to prevent recurrences. While the current mainstay relies on vitamin K antagonists, their long-term maintenance may remain challenging. OBJECTIVES To report on the safety and the efficacy of oral direct inhibitors of thrombin and factor Xa (ODIs) in antiphospholipid syndrome (APS). METHODS We performed a descriptive analysis of patients with APS enrolled in a French multicentre observational cohort between January 2012 and March 2014 and receiving ODIs. The main outcomes were the occurrence of a thrombotic recurrence or bleeding events. RESULTS Twenty-six patients with APS (primary in 12) received ODIs. Twenty patients had been previously treated with VKA (n=19), or fondaparinux (n=1) for a median duration of 3years. ODIs were introduced as second-line therapy because of INR lability/therapeutic simplification (n=17), recurrent thrombosis (n=1), VKAs associated bleeding event (n=1), and atrial fibrillation (n=1). Six patients received ODIs as first-line therapy. After a median [IQR] follow-up of 19 [8-29] months, one relapse of arterial thrombosis, two bleeding events (hypermenorrhea and rectal bleeding under rivaroxaban) and one recurrent migraine were reported, leading to discontinuation of therapy in these 4 patients. CONCLUSION ODIs might be an alternative therapeutic option in APS. Prospective studies are warranted to evaluate their safety in this condition.

Behçet's Disease and Pregnancy

OBJECTIVE To describe the interplay between Behçets disease (BD) and pregnancy. METHODS This retrospective study included 76 pregnancies in 46 patients fulfilling the international criteria for BD. The median age of the patients at the time of entry into the study was 28.4 years (interquartile range 22.8-30.9 years). Patients were used as their own historical controls to assess the incidence of BD flares during pregnancy and before or after pregnancy. Factors associated with the occurrence of complications during pregnancy were assessed. RESULTS Among the 76 pregnancies with BD analyzed, 27 (35.5%) were associated with worsening of the symptoms of BD flare; oral and genital ulcerations (78.4% and 67.6%, respectively) as well as ocular complications (32.4%) were the most frequent. The mean ± SD annual rates of BD flares were 0.49 ± 0.72 during pregnancy and 1.46 ± 2.42 during the nonobstetric period (P = 0.018). The proportion of BD flares tended to be lower in patients treated with colchicine (27.9% versus 45.4% of patients not treated with colchicine; P = 0.11). The overall rate of complications during pregnancy was 15.8%. The complications included miscarriage (5 patients), cesarean delivery (3 patients), medical termination of pregnancy (2 patients), hemolysis, elevated liver enzymes, and low platelets syndrome (1 patient), and immune thrombocytopenia (1 patient). There was a statistically significant association between a history of deep vein thrombosis in BD and the risk of obstetric complications (odds ratio 7.25, 95% confidence interval 1.21-43.46, P = 0.029). Neither gestational age at delivery nor neonatal outcome was influenced by BD. CONCLUSION The disease course in BD seems to improve during pregnancy, mostly in patients who are treated with colchicine. Pregnancy in patients with BD appears not to be associated with an increased rate of pregnancy-related complications.

Hemolysis and schistocytosis in the emergency department: consider pseudothrombotic microangiopathy related to vitamin B12 deficiency

BACKGROUND Hemolytic anemia with thrombocytopenia and schistocytosis is suggestive of thrombotic thrombocytopenic purpura (TTP). However, these features can occur in the context of vitamin B12 deficiency. AIM To identify simple means of distinguishing between TTP and pseudothrombotic microangiopathies related to vitamin B12 deficiency (pseudo-TMA) at the bedside. DESIGN AND METHODS Retrospective study of patients with pseudo-TMA compared with patients with TTP. The patients with pseudo-TMA were further compared with other cases of cobalamin deficiency, in order to detect factors associated with microangiopathic hemolysis during vitamin B12 deprivation. RESULTS Seven patients with pseudo-TMA were compared with six patients with TTP. The pseudo-TMA patients had higher median lactate dehydrogenase (LDH) levels (7310 vs. 1460 IU/l, P = 0.01), a higher platelet count (73 vs.12.5 × 10(9)/l, P = 0.0023), a lower reticulocyte count (13.1 vs. 265.5 × 10(9)/l, P = 0.0012) and a lower neutrophil count (1.3 vs. 5.1 × 10(9)/l, P = 0.0023). When compared with 21 patients with vitamin B12 deficiency and anemia (but no schistocytosis), the pseudo-TMA patients were more likely to present with pernicious anemia [7 out of 21 (33.3%) vs. 5 out of 7 (71.4%), respectively] and had lower vitamin B12 levels (105 vs. 45 µmol/l, respectively). Vitamin supplementation led to hematological improvements in all pseudo-TMA patients. CONCLUSION In a context of mechanical hemolysis with thrombocytopenia in a patient admitted to the emergency department, very high LDH levels and a low reticulocyte count are strongly suggestive of pseudo-TMA and should prompt the physician to screen for cobalamin deficiency.

Long-Term Outcome of Neuro-Behçet's Disease

To report the long‐term outcome of neurologic involvement in patients with Behçets disease (BD).

Small vessel involvement in Takayasu's arteritis

OBJECTIVES To describe the small retinal and systemic vessel involvement in Takayasus arteritis. METHODS We described 3 patients with Takayasus arteritis and small retinal vessel occlusion seen in our department between 2004 and 2011. We performed an extensive literature review and provided a global analysis of small retinal vessel involvement in Takayasu arteritis (i.e., total number of patients analyzed=9). RESULTS Seven patients had small retinal artery occlusion, and two had venous involvement. Four cases were inaugural of the disease (44.4%). Takayasus arteritis was extended (Type V) in the majority of patients presenting with small retinal vessel occlusion (5/9, 55.6%), and 8/9 reported cases (88.9%) presented with involvement of the supra-aortic branches. Immunosuppressive regimen allowed an improvement in 5/9 patients and stabilization in 1/9, but the situation worsened in 3/9 patients. The visual outcome was severe, and 3/9 patients (33.3%) experienced irreversible blindness. CONCLUSION Occlusion of small retinal vessels is a rare and severe microcirculatory complication in Takayasus arteritis, as well as necrotizing cutaneous vasculitis or myocarditis. Small retinal vessel involvement can be inaugural of the disease and seriously impact the visual prognosis in TA patients.

Long-Term Spontaneous Control of HIV-1 Is Related to Low Frequency of Infected Cells and Inefficient Viral Reactivation.

ABSTRACT HIV establishes reservoirs of infected cells that persist despite effective antiretroviral therapy (ART). In most patients, the virus begins to replicate soon after treatment interruption. However, a low frequency of infected cells at the time of treatment interruption has been associated with delayed viral rebound. Likewise, individuals who control the infection spontaneously, so-called HIV-1 controllers (HICs), carry particularly low levels of infected cells. It is unclear, however, whether and how this small number of infected cells contributes to durable viral control. Here we compared 38 HICs with 12 patients on effective combined antiretroviral therapy (cART) and found that the low frequency of infected cells in the former subjects was associated both with less efficient viral reactivation in resting CD4+ T cells and with less efficient virion production ex vivo. We also found that a potent HIV-specific CD8+ T cell response was present only in those HICs whose CD4+ T cells produced virus ex vivo. Long-term spontaneous control of HIV infection in HICs thus appears to be sustained on the basis of the inefficient reactivation of viruses from a limited number of infected cells and the capacity of HICs to activate a potent HIV-specific CD8+ T cell response to counteract efficient viral reactivation events. IMPORTANCE There is a strong scientific interest in developing strategies to eradicate the HIV-1 reservoir. Very rare HIV-1-infected patients are able to spontaneously control viremia for long periods of time (HIV-1 controllers [HICs]) and are put forward as a model of HIV-1 remission. Here, we show that the low viral reservoirs found in HICs are a critical part of the mechanisms underlying viral control and result in a lower probability of HIV-1 reactivation events, resulting in limited HIV-1 release and spread. We found that those HICs in whom viral reactivation and spread from CD4+ T cells in vitro were the most difficult were those with diminished CD8+ T cell responses. These results suggest that, in some settings, low HIV-1 reservoirs decisively contribute to at least the temporary control of infection without antiretroviral therapy. We believe that this work provides information of relevance in the context of the search for HIV-1 remission.

Immunologic and Virologic Progression in HIV Controllers: The Role of Viral "Blips" and Immune Activation in the ANRS CO21 CODEX Study.

Some HIV controllers (HICs) experience CD4+T cell count loss and/or lose their ability to control HIV. In this study, we investigated the rate of immunologic and/or virologic progression (ImmP/VirP) and its determinants in the ANRS CO21/CODEX cohort. Immunologic progression was defined as a lasting fall in CD4+T cell count below 350/mm3 or more than 200/mm3 with a baseline count below 600/mm3. Virologic progression was defined as a HIV viral load (VL) above 2000 copies/mL on two consecutive determinations. Clinical characteristics, immune activation, ultrasensitive HIV VL and total HIV DNA were analyzed. Disease progression was observed in 15 of the 217 patients followed up between 2009 and 2013 (ImmP, n = 10; VirP, n = 5). Progressors had higher ultrasensitive HIV RNA levels at inclusion (i.e. 1-2 years before progression) than non-progressors. ImmP had also lower CD4+T cell nadir and CD4+T cell count at inclusion, and VirP had higher HIV DNA levels in blood. T cell activation and IP10 levels at inclusion were significantly higher in ImmP than in non-progressors. In summary, the lasting loss of CD4+T cells, residual HIV replication and basal levels of immune activation appear to be major determinants of progression in HICs. These factors should be considered for adjusting their follow-up.