41884. Despite Highly Active Antiretroviral Therapy HIV+ Adults Have a Skewed Differentiation of T cell Populations and Decreased CD4+ T cell Immunity to Measles and Varicella Antigens
Session: Poster Abstract Session: Medical Student Poster Session
Friday, October 4, 2013
Room: Yerba Buena Ballrooms
Background:

Highly active antiretroviral therapy (HAART) improves CD4+ T cell counts in the majority of HIV+ adults yet little is known about the recovery of their T cell functional immunity.

Methods:

CD4+ T cell phenotypes and measles and varicella specific CD4+T cell responses were measured in 23 HIV + and 29 HIV- adults using flow cytometry. All participants were currently on HAART and had a history of measles vaccination and varicella infection prior to HIV infection.

Results:

HIV+ individuals had a higher percentage of CD4+ T-cells of the CD4+CD45RO+ memory phenotype (68%±4.9%) compared to HIV- individuals (45%±4.9%; p=0.02).  When HIV+ individuals were stratified by CD4+ nadir of >200 vs. ≤200 cells/uL, both groups showed significantly higher percentage of memory phenotype compared to HIV- individuals (59%±8.7% and 74%±5.1%; p=0.01).  The percentage of CD4+ T-cells of the memory effector phenotype (CD4+ CD45RO+CCR7low) was higher in HIV+ vs. HIV- individuals (41%±3.7% vs. 15%±1.9%; p=.001). Following measles vaccine stimulation, HIV-individuals, HIV+ individuals with CD4+ nadir >200, and HIV+ individuals with CD4+ nadir ≤200 had significantly different absolute numbers of memory helper T-cell responses (CD4+CD45RO+CD69+IFNg+) were 3.6±0.6, 2.8±1.0, and 1.3±0.5 events, respectively (p=0.04). Stimulation with varicella vaccine also showed a significant difference with 12.6±2.3, 8.7±1.6 and 2.7±0.8 events (p<0.01).  Compared to HIV- individuals, HIV+ individuals were 2.7 times (95% CI, 1.23-6.07)  and 1.7 times (95% CI, 1.03-2.66) more likely to have nonresponse to measles vaccine and varicella vaccine stimulation, respectively.

Conclusion:

Despite numerical immune reconstitution, HIV+ adults receiving HAART demonstrate immune abnormalities. There is differentiation of CD4+ T cell phenotypes to a memory effector CD4+ T cell which is affected further by history of CD4+ nadir<200.  In addition, fewer HIV+ adults showed memory responses to measles and varicella despite prior antigen exposure.  This data supports further research to define the mechanisms activating the immune system in HIV+ individuals receiving HAART and re-immunization studies to evaluate both acute and persistent vaccine immunity in this population.

Joshua M. Wong, BA1, Linda Lew Yasukawa, BA2, Stacy Kobayashi, RN2, Andrew R. Zolopa, MD2 and Hayley A. Gans, MD2, (1)Harvard Medical School, Boston, MA, (2)Stanford University Medical Center, Stanford, CA

Disclosures:

J. M. Wong, None

L. L. Yasukawa, None

S. Kobayashi, None

A. R. Zolopa, None

H. A. Gans, None

Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.