803. CD8+ T Cells Predict Risk for Bacterial Pneumonia and All-Cause Mortality in HIV+ Women
Session: Abstracts: Oral Abstract Session: HIV Complications and Pathogenesis
Friday, October 22, 2010: 2:15 PM
118-120
Background: Human Immunodeficiency Virus (HIV)-infected individuals are at markedly higher risk for pneumonia than HIV-uninfected individuals.  This risk is present across all CD4+ T cell levels, suggesting that additional factors may govern disease susceptibility.  This study was undertaken to determine if CD8+ T cell levels (CD8 levels) influence risk for bacterial pneumonia and all-cause mortality. 

Methods: Demographic, clinical, and laboratory data were obtained for 885 HIV-infected (HIV+) and 425 HIV-uninfected (HIV-) women enrolled in the HIV Epidemiologic Research Study (HERS) between 4/1993 and 1/1995.  Bacterial pneumonia cases were identified per published criteria (Kohli, et.al, CID2006;43:90-8).  CD8 levels obtained at 6 month intervals were assessed until the pneumonia event for HIV+ subjects who developed pneumonia, and until last available for those who did not.  Statistical methods included Cox proportional hazards regression modeling with time-varying covariates and estimated Kaplan-Meier survival curves.

Results: Relative to a referent CD8 level of <400 cells/ mm3, the risk for bacterial pneumonia was significantly lower when the CD8 level was 401-800 (p<0.01, HR 0.59, 95% CI 0.39-0.90).  This relationship remained statistically significant after adjusting for age, CD4+ T cell level, viral load, and duration of antiretroviral therapy.  Kaplan-Meier analysis revealed that 72% of subjects with CD8 levels between 401-800 cells/ mm3 were pneumonia-free five years from study entry, compared to 56% of patients with CD8 levels < 400 cells/ mm3.  Secondary analysis for all-cause mortality yielded similar results.

Conclusion: A CD8+ T cell level between 401-800 cells/mm3 was independently associated with decreased risk for bacterial pneumonia and all-cause mortality.  To our knowledge, this is the first study to associate CD8 level with HIV-associated bacterial pneumonia and to associate specific CD8 ranges with all-cause mortality.  Our data provide population-based evidence suggesting a possible role for CD8+ T cells in HIV-associated pneumonia.  We propose that CD8+ T cell level deserves further consideration as a possible marker of the risk for bacterial pneumonia and mortality.


Subject Category: H. HIV/AIDS and other retroviruses

Speakers:
Shruti K. Gohil, MD, MPH , Division of Infectious Diseases, Montefiore Medical Center/ Albert Einstein College of Medicine, Bronx, NY
Moonseong Heo, PhD , Department of Epidemiology and Population Health, Montefiore Medical Center/ Albert Einstein College of Medicine, Bronx, NY
Ellie E. Schoenbaum, MD , Department of Epidemiology and Population Health, Montefiore Medical Center/ Albert Einstein College of Medicine, Bronx, NY
David Celentano, ScD , Department of Epidemiology, Johns Hopkins University, Baltimore, MD
Charles Carpenter, MD , Brown Medical School, Providence, RI
Liise-anne Pirofski, MD, FIDSA , Division of Infectious Diseases, Albert Einstein College of Medicine, Bronx, NY

Disclosures:

S. K. Gohil, None

M. Heo, None

E. E. Schoenbaum, None

D. Celentano, None

C. Carpenter, None

L. A. Pirofski, None


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