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William J. Janssen

William J. Janssen, MD, is a pulmonologist at National Jewish Health. Dr. Janssen serves as the Section Head of Critical Care Medicine.

Special Interests

Clinical Interests

My clinical interests are in critical care medicine and chronic obstructive pulmonary disease. I also specialize in the treatment of septic shock, acute lung injury, and ARDS (acute respiratory distress syndrome).


Research Interests

My research is focused on mechanisms of repair following acute and chronic lung injury. This includes studying how lung collectins influence alveolar macrophage phenotype, function, and fate in healthy lungs and during inflammation. I am also interested in the role that bone-marrow-derived stem cells (including endothelial progenitor cells) play in recovery from lung injury.



1994 - 1998
The Ohio State University, MD
The Ohio State University, BS, Mechanical Engineering


1998 - 2001
The Ohio State University, Internal Medicine


2002 - 2005
University of Colorado Denver, Pulmonary and Critical Care

Awards & Recognition

2014: Best Doctors in America, Best Doctors, Inc.

Board Certification

Internal Medicine,
Pulmonary Medicine,
Critical Care

Professional Memberships

American Thoracic Society
Society of Critical Care Medicine
American College of Chest Physicians


Sareli AE, Janssen WJ, Sterman D, Saint S, Pyeritz RF. What’s the connection? New Eng J. Med. 2008; 358(6):626-32.

Ezzie E, Janssen WJ, O’Brien, JM, Fox C, Schwarz MI. Failure to respond, New Eng J Med. 2008; 358(1):70-4.

Linderman DL, Janssen WJ. Critical care medicine for the hospitalist. Med Clin N. America 2008;92:467–479.

Janssen WJ, McPhillips KA, Dickinson MG, Derek J. Linderman DJ, Morimoto K, Xiao YQ, Oldham KM, Vandivier RW,Henson PM, Gardai SJ.Surfactant Proteins A and D Tonically Suppress Alveolar Macrophage Phagocytosis via Interaction with SIRP?. Am J Respir Cell Crit Care Med. 2008;178)2):158-67

McPhillips K, Janssen WJ, Ghosh M, Byrne A, Gardai SJ, Remigio L, Bratton DL, Kang JL, Henson PM. TNFa inhibits macrophage clearance of apoptotic cells via cPLA2 and oxidant-dependent mechanisms. J Immunol. 2007;178(12):8117-2612.

Hospital Affiliations

  • Colorado Acute Long Term Hospital
  • Exempla Lutheran Medical Center
  • Rose Medical Center
  • Sky Ridge Medical Center
  • St. Joseph Hospital - Denver
  • Swedish Medical Center
  • University of Colorado Hospital

Academic Affiliations

Assistant Professor of Medicine, University of Colorado Denver

Conflicts of Interest

National Jewish Health physicians and scientists may collaborate with pharmaceutical or other industries to develop medical and scientific breakthroughs or to provide education on trends in quality medical practice and outcomes to physicians and health professionals around the country. National Jewish Health maintains a strict conflict of interest policy to ensure that all potential conflicts are clearly visible and that management plans are put in place in order to further innovation and education while ensuring the protection of our patients and the integrity of our research. National Jewish Health publicly discloses any payment to our physicians or scientists. View this faculty member’s industry relationships and collaborations.