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Niel T. Constantine

Niel T. Constantine Ph.D.

Academic Title: Professor
Primary Appointment: Pathology
Additional Title(s): Director, Clinical Immunology
Location: IHV, S215
Phone: (410) 706-2788
Fax: (410) 706-2789
Lab: (410) 706-2214

Personal History:

Dr. Niel T. Constantine, a professor in the Department of Pathology, possesses 35 years of experience in the medical diagnostic arena, acts frequently as an international consultant for laboratory strengthening activities in many countries, and has a productive track record with extramural funding and publications. After obtaining a degree in Medical Technology, he completed his Ph.D. in Pathology at the University of Maryland where he has remained. During this time, he spent 3 years at the U.S. Naval Medical Research Unit #3 in Cairo Egypt where he established and headed a laboratory for HIV surveillance that became a WHO Collaborating Centre for HIV in the Eastern Mediterranean Region. When returning to the University in 1990, he was appointed Director of the Clinical Immunology Laboratory at the UM Medical Center Hospital where a variety of testing is performed, including all serologic testing and lymphocyte phenotyping. During 1993, Dr. Constantine was recruited to Geneva to work with the Global AIDS Programme in the Diagnostics Unit for establishing research protocols in a number of countries, and addressing issues in global diagnostics for HIV. Since that time, Dr. Constantine established the Laboratory of Viral Diagnostics, a strong research unit at the Institute of Human Virology that provides support for several divisions and conducts developmental test research, as well as performing FDA clinical trials.


  • Ph.D. - Pathology, University of Maryland School of Medicine, Baltimore, 1981
  • B.S. - Medical Technology, University of Maryland, Baltimore, 1974
  • B.A. - Psychology, University of Maryland Baltimore County, 1973

Honors and Awards

In 2005, Dr. Constantine received the Innovator of the Year Award from The Daily Record for his work in the development of a test for detection of prions in blood.

Research Interests:

The Laboratory of Viral Diagnostics at the Institute of Human Virology provides serologic and molecular testing capabilities, performs research activities for the development of test technology, provides training for international students, and supports a variety of ancillary activities including sample archiving, quality assurance support, and clinical trials. The staff include persons with Masters degrees in Molecular Biology, a Ph.D., and two laboratory assistants. Efforts are directed toward the development of a variety of novel technologies aimed at increasing sensitivity, simplifying procedures, and developing test technologies for resource-limited facilities in developing countries. Currently, Dr. Constantine is principal investigator for activities supported through grants from the US government and commercial companies. Recent grants included those from NIH for the ultra-sensitive detection of biothreat agents and development of a test to determine recent HIV infection, one from the Department of Defense for development of a blood test to detect prion protein, and industrial support for several FDA clinical trials involving HIV tests. The laboratory has been a clinical site for all 8 FDA-licensed rapid HIV tests. A major emphasis in the Laboratory of Viral Diagnostics includes new test development for the ultrasensitive detection of HIV proteins. Methods are being developed that incorporate signal amplification strategies for routine protein and antigen detection, both in high throughput and rapid/simple test configurations. Immuno-PCR that couples molecular and serologic capture methods is being explored with unique modifications of basic concepts to offer reduced background with more simplified real-time detection methods. Theoretical potentials allow for the detection of HIV p24 antigen earlier than that offered by PCR testing for HIV RNA. Other signal amplification strategies, appropriate for resource-limited countries, include those for increasing colorimetric endpoints for both membrane-based assay configurations as well as on microsphere-coated particles that utilize battery-operated platforms. Other activities include development and assessment of sensitive/less sensitive assays to offer more efficient ways to enroll recently-infected persons into intervention programs.

Lab Techniques and Equipment:

Serologic Assays, Molecular Assays, Rapid Test Technology.

Consulting Activities:

Major consultant activities include those from the World Bank, USAID, and the WHO for laboratory strengthening in the countries of Egypt, Thailand, Uganda, India, Haiti, the Ukraine, Indonesia, and the Philippines, all of which resulted in a number of demonstrable improvements in laboratory expertise and capabilities. Dr. Constantine has also been recruited by the WHO to assist with the Global Alliance for Vaccine Initiative (GAVI), and has worked closely with the CDC for HIV testing activities in Nigeria.

Clinical Specialty:

Immunology and Infectious Diseases, Diagnostics.


Dr. Constantine's efforts have resulted in the publication of over 130 articles, including two books, 10 book chapters and nearly 200 abstracts, most of which describe new technologies and their applications. Of particular note is his book on Retroviral Testing and Quality Assurance (2005) that is used in laboratories throughout the world. The non-profit, 700 page book, is targeted to laboratory personnel, program managers, and international agencies.

Selected Publications:

Constantine, N.T., Sill, A.M., Jack, N., Kreisel, K., Edwards, J., Cafarella, T., Smith, H., Bartholomew, C., Cleghorn, F., and Blattner, W.A.: Improved classification of recent HIV-1 infection by employing a two-stage sensitive/less sensitive test strategy. JAIDS, 32: 94-103, 2003.

Barletta, J.M., Edelman, D.C., & Constantine, N.T. Lowering the detection limits of HIV-1 viral load using real-time immuno-PCR for HIV-1 p24 antigen. American Journal of Clinical Pathology, 122: 20-27, 2004.

Barletta, J.M., Edelman, D.C., Highsmith, W.E., & Constantine, N.T. Detection of ultra-low levels of pathologic prion protein in scrapie infected hamster brain homogenates using real-time immuno-PCR. Journal of Virological Methods, 127:154-164, 2005.

Constantine, N.T., Saville, R., and Dax, E.: Retroviral Testing and Quality Assurance: Essentials for Laboratory Diagnosis. (Book) Malloy Printers, 2005.

Barletta, J., Bartolome, A., Constantine, N.T. Immunomagnetic quantitative immuno-PCR for detection of less than one HIV-1 virion. J. Virol. Meth., 157: 122-132, 2009.

Sajadi, M.M., Constantine, N.T., Mann, D.L., Charurat, M., Dadzan, E., Kadlecik, P., Redfield, R.R. Epidemiologic characteristics and natural history of HIV-1 natural viral suppressors; JAIDS, 50: 403-408, 2009.

Constantine NT and Watson DC. In: Principles of Perinatal & Pediatric AAIDS chapter 6: Virology and laboratory diagnosis of HIV infection in infants and children, Editors: Mamatha Lala and Rashid Merchant; Jaypee Brothers, Lt. Ed., ISBN: 978-93-5025-197-3, India, 2011.

Rosenberg, E, Brennan, C, Claessens, C, Constantine, N, Murphy, G, Owen, S, Werner, B, Yao, J, Yen-Lieberman, B, Branson, B, Garrett, P, Howell, R. Criteria for laboratory testing and diagnosis of HIV infection. CLSI, M53-P, Vol. 30, Number 21, ISBN: 1-56238-735-9, 2011.

Zhang, Y, Traskman-Bendz, L, Janelidze, S, Langenberg, P, Constantine, N, Saleh, A, Okusaga, O, Bay-Richter, C, Brundin, L, Postolache, TT. Toxoplasma gondii IgG antibodies and non-fatal suicidal self-directed violence. J Clin Psych. 73: 1069-1076, 2012.

Ahmed, S, Delaney, K; Villalba-Diebold, P, Aliyu, G, Constantine, NT, Ememabelem, M; Vertefeuille, J, Blattner, W, Nasidi, A; Charurat, M. HIV counseling and testing and access to care needs of populations most-at-risk for HIV in Nigeria. AIDS Care, 25: 85-94, 2013.

Constantine, N, Wright, PA, Saleh, A, DeMarinis, A. The impact of molecular testing on the blood bank. In Molecular Diagnostics: 14 Tests that changed everything; A volume in the series: Molecular and Personalized Medicine; WB Coleman and GJ Tsongalis (Series Eds), W Highsmith (Ed); Springer, 2014.

Nkeze, J, Constantine, N, Zhao, RY. Laboratory testing for HIV infection: advances after 27 years. In Molecular Diagnostics: 14 Tests that changed everything; A volume in the series: Molecular and Personalized Medicine; WB Coleman and GJ Tsongalis (Series Eds), W Highsmith (Ed); Springe, 2014.

Wei Luo, Silvina Masciotra, Kevin Delaney, Man Charurat, Taeleisha Croxton, Niel Constantine, Abdulsalami Nasidi, William Blattner, Laura Wesolowski, S. Michele Owen. Comparison of HIV Oral Fluid and Plasma Testing during Early Infection in a Longitudinal Nigerian Cohort. J Clin Virol; In press, 2014.