Lee J. Quinton, Ph.D.
Assistant Professor of Medicine
BS, University of Southern Mississippi
PhD, Louisiana State University Health Sciences Center
Postdoctoral Training, Louisiana State University Health Sciences Center & Harvard School of Public Health
Lung infections account for a tremendous burden of disease, representing the most frequent cause of infection-related deaths and a common cause of acute lung injury. The innate immune response is critical for the prevention of lower respiratory tract infections. Yet, this response must be tightly regulated, such that adequate host defenses do not result in inflammatory lung injury. Our long-term goal is to elucidate intra- and extra-pulmonary signaling events required for an immune response that is both effective and balanced. The local response to lung infections includes neutrophil recruitment, expression of soluble mediators such as cytokines, and the extravasation of plasma constituents from the vascular space into the alveolar space. The result is an inflammatory milieu and cellular composition that promotes local immune responsiveness. This physiologic transition within the lung, however, occurs in tandem with a systemic acute phase response (APR), typified by altered circulating levels of acute phase proteins (APPs). While the APR has long been recognized as a useful biomarker of disease progression during pneumonia, the collective impact of APPs on inflammation and host defense are unknown. We have recently shown that the cytokines TNF-alpha, IL-1, and IL-6, which are critical for maximal host defense during pneumonia, are also essential for the activation of downstream transcription factors and the expression of APPs in the liver. Therefore, the hepatic APR may be a systemic conduit through which select cytokines promote the immune response to lung infection. Understanding how APPs and other extra-pulmonary factors integrate with local responses in the lung to promote immunity and tissue protection during pneumonia will help to identify novel prognostic indicators and therapeutics for this important disease.