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Introduction The chemokine CXCL12 and its cognate receptor CXCR4 perform multiple functions essential for CNS development and function, including guiding migration and differentiation of neuronal precursor cells (1), regulating cell [...], Interaction of the chemokine CXCL12 with its receptor CXCR4 promotes neuronal function and survival during embryonic development and throughout adulthood. Previous studies indicated that μ-opioid agonists specifically elevate neuronal levels of the protein ferritin heavy chain (FHC), which negatively regulates CXCR4 signaling and affects the neuroprotective function of the CXCL12/CXCR4 axis. Here, we determined that CXCL12/CXCR4 activity increased dendritic spine density, and also examined FHC expression and CXCR4 status in opiate abusers and patients with HIV-associated neurocognitive disorders (HAND), which is typically exacerbated by illicit drug use. Drug abusers and HIV patients with HAND had increased levels of FHC, which correlated with reduced CXCR4 activation, within cortical neurons. We confirmed these findings in a nonhuman primate model of SIV infection with morphine administration. Transfection of a CXCR4-expressing human cell line with an iron-deficient FHC mutant confirmed that increased FHC expression deregulated CXCR4 signaling and that this function of FHC was independent of iron binding. Furthermore, examination of morphine-treated rodents and isolated neurons expressing FHC shRNA revealed that FHC contributed to morphine-induced dendritic spine loss. Together, these data implicate FHC-dependent deregulation of CXCL12/CXCR4 as a contributing factor to cognitive dysfunction in neuroAIDS.

Introduction Depletion of [CD4.sup.+] T cells, the defining characteristic for which the immunodeficiency viruses HIV-1 and SIV were named, has been attributed to direct mechanisms of infection and cell killing [...], The hallmark of HIV-1 and SIV infections is [CD4.sup.+] T cell depletion. Both direct cell killing and indirect mechanisms related to immune activation have been suggested to cause the depletion of T cells. We have now identified a mechanism by which immune activation-induced fibrosis of lymphoid tissues leads to depletion of naive T cells in HIV-1 infected patients and SIV-infected rhesus macaques. The T regulatory cell response to immune activation increased procollagen production and subsequent deposition as fibrils via the TGF-β1 signaling pathway and chitinase 3-like-1 activity in fibroblasts in lymphoid tissues from patients infected with HIV-1. Collagen deposition restricted T cell access to the survival factor IL-7 on the fibroblastic reticular cell (FRC) network, resulting in apoptosis and depletion of T cells, which, in turn, removed a major source of lymphotoxin-β, a survival factor for FRCs during SIV infection in rhesus macaques. The resulting loss of FRCs and the loss of IL-7 produced by FRCs may thus perpetuate a vicious cycle of depletion of T cells and the FRC network. Because this process is cumulative, early treatment and antifibrotic therapies may offer approaches to moderate T cell depletion and improve immune reconstitution during HIV-1 infection.

Clearance of viral infections requires potent T cell responses. However, in HIV and other chronic viral infections, viral persistence (1,2) leads to the decay of [CD4.sup.+] T cells and their [...], Viral replication and microbial translocation from the gut to the blood during HIV infection lead to hyperimmune activation, which contributes to the decline in [CD4.sup.+] T cell numbers during HIV infection. Programmed death-1 (PD-1) and interleukin-10 (IL-10) are both upregulated during HIV infection. Blocking interactions between PD-1 and programmed death ligand-1 (PD-L1) and between IL-10 and IL-10 receptor (IL-10R) results in viral clearance and improves T cell function in animal models of chronic viral infections. Here we show that high amounts of microbial products and inflammatory cytokines in the plasma of HIV-infected subjects lead to upregulation of PD-1 expression on monocytes that correlates with high plasma concentrations of IL-10. Triggering of PD-1 expressed on monocytes by PD-L1 expressed on various cell types induced IL-10 production and led to reversible [CD4.sup.+] T cell dysfunction. We describe a new function for PD-1 whereby microbial products inhibit T cell expansion and function by upregulating PD-1 levels and IL-10 production by monocytes after binding of PD-1 by PD-L1.

Introduction After the development of penicillin, the number of syphilis cases fell to its lowest level in 2000 in the United States, from 20.3 cases per 100,000 people to 2.9 [...], Introduction: Outbreaks of syphilis have been described among HIV-infected men who have sex with men (MSM) in Western communities, whereas reports in Asian countries are limited. We aimed to characterize the incidence and temporal trends of syphilis among HIV-infected MSM compared with HIV-infected non-MSM in Asian countries. Methods: Patients enrolled in the TREAT Asia HIV Observational Database cohort and with a negative non-treponemal test since enrolment were analyzed. Incidence of syphilis seroconversion, defined as a positive non-treponemal test after previously testing negative, was evaluated among patients at sites performing non-treponemal tests at least annually. Factors associated with syphilis seroconversion were investigated at sites doing non-treponemal testing in all new patients and subsequently testing routinely or when patients were suspected of having syphilis. Results: We included 1010 patients from five sites that performed non-treponemal tests in all new patients; those included had negative non-treponemal test results during enrolment and subsequent follow-ups. Among them, 657 patients were from three sites conducting regular non-treponemal testing. The incidence of syphilis seroconversion was 5.38/100 person-years (PY). Incidence was higher in MSM than non-MSM (7.64/100 PY vs. 2.44/100 PY, p Conclusions: We observed a higher incidence of syphilis seroconversion among HIV-infected MSM and a trend to increasing annual incidence. Regular screening for syphilis and targeted interventions to limit transmission are needed in this population. Keywords: syphilis; incidence; seroconversion; HIV; MSM.

Introduction Tuberculosis is a major global health problem, ranking as the second leading cause of death from an infectious disease [1]. Individuals who are more often exposed to Mycobacterium tuberculosis, [...], Introduction: Injecting drug use (IDU) is associated with tuberculosis but few data are available from low-income settings. We examined IDU in relation to active and latent tuberculosis (LTBI) among HIV-positive individuals in Indonesia, which has a high burden of tuberculosis and a rapidly growing HIV epidemic strongly driven by IDU. Methods: Active tuberculosis was measured prospectively among 1900 consecutive antiretroviral treatment (ART)-naVve adult patients entering care in a clinic in West Java. Prevalence of LTBI was determined cross-sectionally in a subset of 518 ARTexperienced patients using an interferon-gamma release assay. Results: Patients with a history of IDU (53.1%) more often reported a history of tuberculosis treatment (34.8% vs. 21.9%, p < 0.001), more often received tuberculosis treatment during follow-up (adjusted HR = 1.71; 95% CI: 1.25-2.35) and more often had bacteriologically confirmed tuberculosis (OR = 1.67; 95% CI: 0.94-2.96). LTBI was equally prevalent among people with and without a history of IDU (29.1 vs. 30.4%, NS). The risk estimates did not change after adjustment for CD4 cell count or ART. Conclusions: HIV-positive individuals with a history of IDU in Indonesia have more active tuberculosis, with similar rates of LTBI. Within the HIV clinic, LTBI screening and isoniazid preventive therapy may be prioritized to patients with a history of IDU. Keywords: cohort studies; Mycobacterium tuberculosis; human immunodeficiency virus; substance abuse; intravenous; latent tuberculosis infection.