1321. Neutrophil Function in Elderly Patients Hospitalized with Community-Acquired Pneumonia (CAP): Results from the Community-Acquired Pneumonia Inflammatory Study Group (CAPISG)
Session: Poster Abstract Session: Biomarkers and Correlates of Protection
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background:

An abnormal immune response in the elderly (immunosenescence) places this population at risk for poor outcomes during an episode of CAP. The role of neutrophil function (NF) in immunosenescence is not well defined.  The objective of this study was to compare NF in elderly versus non-elderly patients hospitalized with CAP.

Methods:

This was a prospective study of non-elderly (age <65yo) and elderly (age ≥65yo) hospitalized patients with CAP. Whole blood drawn on the day of hospital admission was used to determine NF through flow cytometry by measuring plasma membrane expression of CD35 (marker of secretory vesicles) and CD66b (marker of specific granules), determining phagocytosis of opsonized propidium iodide-labeled Staphylococcus aureus (Ph-Sa), and H2O2 production in phagosomes (marker of respiratory burst). Differences in NF were evaluated by Mann-Whitney U-test.

Results:

A total of 28 non-elderly (NE) and 12 elderly (E) patients were enrolled. Median (interquartile range) CD35 expression was 122(130) in NE and 156(67) in E (P=0.768). CD66b expression was 160(125) in NE and 119(158) in E (P=0.271). Ph-Sa was 773(1000) in NE and 1037(513) in E (P=0.520). H2O2 production was 726(418) in NE and 545(501) in E (P=0.393).

Conclusion:

We failed to demonstrate any decreased NF in the elderly when compared to non-elderly hospitalized patients with CAP. This study suggests that abnormal NF is not a component of the immunosenescence described in the elderly.

Jorge Perez San Juan, MD1, Lisandra Rodriguez Hernandez, MD1, Silvia Uriarte, PhD2, Robert Kelley, PhD2, Timothy Wiemken, PhD2, Rafael Fernandez-Botran, PhD3, Martin Gnoni, MD2, Paula Peyrani, MD2, Jose Bordon, MD, PhD4, Madhavi Rane, PhD5, Forest Arnold, DO2 and Julio A. Ramirez, MD1, (1)Infectious Diseases, University of Louisville, Louisville, KY, (2)Division of Infectious Diseases, University of Louisville, Louisville, KY, (3)Pathology and Laboratory Medicine, University of Louisville, Louisville, KY, (4)Section of Infectious Diseases, Providence Hospital, Washington, DC, (5)Division of Nephrology, University of Louisville, Louisville, KY

Disclosures:

J. Perez San Juan, None

L. Rodriguez Hernandez, None

S. Uriarte, None

R. Kelley, None

T. Wiemken, None

R. Fernandez-Botran, None

M. Gnoni, None

P. Peyrani, None

J. Bordon, None

M. Rane, None

F. Arnold, None

J. A. Ramirez, None

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