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Tracy Fischer-Smith, PhD

Assistant Professor, Neuroscience

Assistant Professor, Neurovirology

Location: Room 748 MERB

Telephone:  215-707-5005

Fax:  215-707-4888

Email: tlfsmith@temple.edu

Department of Neuroscience

Center for Neurovirology

Bachelor of Music, Ohio Northern University, Ada, OH, 1992

 

Master of Music, Rider University, Lawrenceville, NJ, 1994

 

PhD, Biology, Temple University, Philadelphia, PA, 2005

 

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• Philadelphia Area Chapter Society for Neuroscience
• International Society for NeuroVirology (ISNV)
• Society on Neuroimmune Pharmacology (SNIP)
• American Society for Investigative Pathology (ASIP)

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The major focus of our laboratory involves the investigation into altered monocyte/macrophage homeostasis in HIV infection. We have characterized a monocyte subset that is expanded in the circulation of patients with HIV infection. This subset is CD163+/CD16+ and is found to accumulate in the CNS of patients who died with HIV encephalitis (HIVE). In a single time-point cross sectional analysis of HIV infected individuals with and without virus detection, we found a positive correlation between viral load and percent frequency of this monocyte subset, as well as a significant inverse correlation between CD4+ T cell count and the percent frequency of this monocyte subset in patients with CD4+ T cell counts below 450 cells/µl. We believe that this monocyte subset may be a potential biomarker for HIV/AIDS progression where expansion of these monocytes may provide an earlier window into immune impairment or dysregulation prior to the dramatic loss of CD4+ T cells.

In collaboration with Dr. Ellen Tedaldi, Director of the Temple Comprehensive HIV Program, we’re now expanding our previous study by following a cohort of HIV infected persons longitudinally. For these studies, anti-retroviral therapy (ART)-naïve patients are enrolled prior to the start of ART and followed for 2 years after the initiation of ART. We have studies designed to better understand the kinetics of the expansion of this monocyte subset with regard to viral load and CD4+ T cell count. We are also exploring the immune character of these cells to gain insights into their possible role in disease pathogenesis. In autopsy CNS tissue of patients with HIVE, cells with the same CD163+/CD16+ phenotype selected by laser capture microdissection are being investigated by microarray to better characterize their immune status and role in CNS disease. We’re hoping that these studies will help us better understand the nature of this expanded subset, how it functions in immune activation and how it might contribute to HIVE and AIDS pathogenesis for the identification of potential therapeutic targets.

As part of a larger project investigating the consequence of opioid use to the development of AIDS, our lab is responsible for the pathologic evaluation and characterization of CNS and visceral necropsy tissues from seronegative and SIV infected rhesus macaques. In collaboration with Dr. Tom Rogers, Dr. Jay Rappaport and Dr. Kamel Khalili, we are performing histological studies to explore the effect of opioids on immune modulation and disease progression in the context of HIV infection and AIDS, using SIVmac251-infected and morphine-treated Indian rhesus macaques.

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Recent Medically Related Publications, Obtained from PubMed (Click on PubMed ID to view abstract)

18780233. Fischer-Smith T, Bell C, Croul S, Lewis M, Rappaport J, Monocyte/macrophage trafficking in acquired immunodeficiency syndrome encephalitis: lessons from human and nonhuman primate studies. J Neurovirol 14:4(318-26)2008 Aug

18373432. Fischer-Smith T, Tedaldi EM, Rappaport J, CD163/CD16 coexpression by circulating monocytes/macrophages in HIV: potential biomarkers for HIV infection and AIDS progression. AIDS Res Hum Retroviruses 24:3(417-21)2008 Mar

18040789. Haine V, Fischer-Smith T, Rappaport J, Macrophage colony-stimulating factor in the pathogenesis of HIV infection: potential target for therapeutic intervention. J Neuroimmune Pharmacol 1:1(32-40)2006 Mar

17670818. Mueller YM, Petrovas C, Do DH, Altork SR, Fischer-Smith T, Rappaport J, Altman JD, Lewis MG, Katsikis PD, Early establishment and antigen dependence of simian immunodeficiency virus-specific CD8+ T-cell defects. J Virol 81:20(10861-8)2007 Oct

16321172. Fischer-Smith T, Rappaport J, Evolving paradigms in the pathogenesis of HIV-1-associated dementia. Expert Rev Mol Med 7:27(1-26)2005 Dec 2

15161643. Fischer-Smith T, Croul S, Adeniyi A, Rybicka K, Morgello S, Khalili K, Rappaport J, Macrophage/microglial accumulation and proliferating cell nuclear antigen expression in the central nervous system in human immunodeficiency virus encephalopathy. Am J Pathol 164:6(2089-99)2004 Jun

11704885. Fischer-Smith T, Croul S, Sverstiuk AE, Capini C, L'Heureux D, Régulier EG, Richardson MW, Amini S, Morgello S, Khalili K, Rappaport J, CNS invasion by CD14+/CD16+ peripheral blood-derived monocytes in HIV dementia: perivascular accumulation and reservoir of HIV infection. J Neurovirol 7:6(528-41)2001 Dec

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