John Fahy, MSc, MD


Dr. John Fahy is a pulmonologist at UCSF Medical Center who has a special interest in treating patients with asthma. Fahy directs the severe asthma clinic at UCSF. He also cares for critically ill patients in the medical center's intensive care units.

As a researcher, he directs the UCSF Airway Clinical Research Center. At the center he receives funding from the National Institutes of Health and foundations, as well as contracts from biotechnology and pharmaceutical companies to conduct clinical research in asthma, cystic fibrosis and other airway diseases to uncover underlying disease mechanisms.

Fahy earned a medical degree at University College Dublin in Ireland in 1985. After internal medicine training in Dublin, he completed pulmonary and critical care fellowship training at UCSF and joined the faculty in 1993 in the Pulmonary and Critical Care Division. He is a professor in residence in the UCSF School of Medicine, where he holds the Michael S. Stulbarg Endowed Chair in Pulmonary Medicine.


Asthma Clinic
400 Parnassus Ave., Fifth Floor
San Francisco, CA 94143-0359
Phone: (415) 353-2961

Hours: Thursdays
8:30 – 11:30 a.m.

Pulmonary Practice at Parnassus
400 Parnassus Ave., Fifth Floor
San Francisco, CA 94143-0359
Phone: (415) 353-2961
Fax: (415) 353-2568

Hours: Monday to Friday
8 a.m. – 5 p.m.

Conditions & Treatments

  • Severe Asthma

Board Certification

Internal Medicine

More about John Fahy


University College, Dublin Ireland 1985


University College Dublin, Internal Medicine 1989


UCSF, Pulmonary Medicine 1992

Selected Research and Publications

  1. Bhakta NR, Christenson SA, Nerella S, Solberg OD, Nguyen CP, Choy DF, Jung KL, Garudadri S, Bonser LR, Pollack JL, Zlock LT, Erle DJ, Langelier C, Derisi JL, Arron JR, Fahy JV, Woodruff PG. Interferon-stimulated Gene Expression, Type-2 Inflammation and Endoplasmic Reticulum Stress in Asthma. Am J Respir Crit Care Med. 2017 Oct 24.
  2. Pavord ID, Beasley R, Agusti A, Anderson GP, Bel E, Brusselle G, Cullinan P, Custovic A, Ducharme FM, Fahy JV, Frey U, Gibson P, Heaney LG, Holt PG, Humbert M, Lloyd CM, Marks G, Martinez FD, Sly PD, von Mutius E, Wenzel S, Zar HJ, Bush A. After asthma: redefining airways diseases. Lancet. 2017 Sep 11.
  3. Teague WG, Phillips BR, Fahy JV, Wenzel SE, Fitzpatrick AM, Moore WC, Hastie AT, Bleecker ER, Meyers DA, Peters SP, Castro M, Coverstone AM, Bacharier LB, Ly NP, Peters MC, Denlinger LC, Ramratnam S, Sorkness RL, Gaston BM, Erzurum SC, Comhair SAA, Myers RE, Zein J, DeBoer MD, Irani AM, Israel E, Levy B, Cardet JC, Phipatanakul W, Gaffin JM, Holguin F, Fajt ML, Aujla SJ, Mauger DT, Jarjour NN. Baseline Features of the Severe Asthma Research Program (SARP III) Cohort: Differences with Age. J Allergy Clin Immunol Pract. 2017 Aug 30.
  4. Lachowicz-Scroggins ME, Finkbeiner WE, Gordon ED, Yuan S, Zlock L, Bhakta NR, Woodruff PG, Fahy JV, Boushey HA. Corticosteroid and long-acting ▀-agonist therapy reduces epithelial goblet cell metaplasia. Clin Exp Allergy. 2017 Aug 22.
  5. Ricklefs I, Barkas I, Duvall MG, Cernadas M, Grossman NL, Israel E, Bleecker ER, Castro M, Erzurum SC, Fahy JV, Gaston BM, Denlinger LC, Mauger DT, Wenzel SE, Comhair SA, Coverstone AM, Fajt ML, Hastie AT, Johansson MW, Peters MC, Phillips BR, Levy BD. ALX receptor ligands define a biochemical endotype for severe asthma. JCI Insight. 2017 Jul 20; 2(14).
  6. Dunican EM, Fahy JV. Asthma and corticosteroids: time for a more precise approach to treatment. Eur Respir J. 2017 Jun; 49(6).
  7. Duvall MG, Barnig C, Cernadas M, Ricklefs I, Krishnamoorthy N, Grossman NL, Bhakta NR, Fahy JV, Bleecker ER, Castro M, Erzurum SC, Gaston BM, Jarjour NN, Mauger DT, Wenzel SE, Comhair SA, Coverstone AM, Fajt ML, Hastie AT, Johansson MW, Peters MC, Phillips BR, Israel E, Levy BD. Natural killer cell-mediated inflammation resolution is disabled in severe asthma. Sci Immunol. 2017 Mar 10; 2(9).
  8. Denlinger LC, Phillips BR, Ramratnam S, Ross K, Bhakta NR, Cardet JC, Castro M, Peters SP, Phipatanakul W, Aujla S, Bacharier LB, Bleecker ER, Comhair SA, Coverstone A, DeBoer M, Erzurum SC, Fain SB, Fajt M, Fitzpatrick AM, Gaffin J, Gaston B, Hastie AT, Hawkins GA, Holguin F, Irani AM, Israel E, Levy BD, Ly N, Meyers DA, Moore WC, Myers R, Opina MT, Peters MC, Schiebler ML, Sorkness RL, Teague WG, Wenzel SE, Woodruff PG, Mauger DT, Fahy JV, Jarjour NN. Inflammatory and Comorbid Features of Patients with Severe Asthma and Frequent Exacerbations. Am J Respir Crit Care Med. 2017 Feb 01; 195(3):302-313.
  9. MacNee W, Fahy JV, Nicod LP, Kolls JK. Purpose of the Conference: 2016 Transatlantic Airway Conference. Ann Am Thorac Soc. 2016 Dec; 13(Supplement_5):S395.
  10. Lachowicz-Scroggins ME, Yuan S, Kerr SC, Dunican EM, Yu M, Carrington SD, Fahy JV. Abnormalities in MUC5AC and MUC5B Protein in Airway Mucus in Asthma. Am J Respir Crit Care Med. 2016 Nov 15; 194(10):1296-1299.
  11. Dickey BF, Fahy JV, Kesimer M, Boucher RC, Evans CM, Thornton D. Measuring Airway Mucin 2 in Patients with Severe Chronic Obstructive Pulmonary Disease with Bacterial Colonization. Ann Am Thorac Soc. 2016 Nov; 13(11):2103-2104.
  12. Luyster FS, Strollo PJ, Holguin F, Castro M, Dunican EM, Fahy J, Gaston B, Israel E, Jarjour NN, Mauger DT, Moore WC, Wenzel SE. Association Between Insomnia and AsthmaáBurden in the Severe Asthma Research Program (SARP) III. Chest. 2016 Dec; 150(6):1242-1250.
  13. Gordon ED, Palandra J, Wesolowska-Andersen A, Ringel L, Rios CL, Lachowicz-Scroggins ME, Sharp LZ, Everman JL, MacLeod HJ, Lee JW, Mason RJ, Matthay MA, Sheldon RT, Peters MC, Nocka KH, Fahy JV, Seibold MA. IL1RL1 asthma risk variants regulate airway type 2 inflammation. JCI Insight. 2016 Sep 08; 1(14):e87871.
  14. Peters MC, Fahy JV. Metabolic consequences of obesity as an "outside in" mechanism of disease severity in asthma. Eur Respir J. 2016 Aug; 48(2):291-3.
  15. Gordon ED, Simpson LJ, Rios CL, Ringel L, Lachowicz-Scroggins ME, Peters MC, Wesolowska-Andersen A, Gonzalez JR, MacLeod HJ, Christian LS, Yuan S, Barry L, Woodruff PG, Ansel KM, Nocka K, Seibold MA, Fahy JV. Alternative splicing of interleukin-33 and type 2 inflammation in asthma. Proc Natl Acad Sci U S A. 2016 Aug 02; 113(31):8765-70.
  16. Peters MC, McGrath KW, Hawkins GA, Hastie AT, Levy BD, Israel E, Phillips BR, Mauger DT, Comhair SA, Erzurum SC, Johansson MW, Jarjour NN, Coverstone AM, Castro M, Holguin F, Wenzel SE, Woodruff PG, Bleecker ER, Fahy JV. Plasma interleukin-6 concentrations, metabolic dysfunction, and asthma severity: a cross-sectional analysis of two cohorts. Lancet Respir Med. 2016 Jul; 4(7):574-84.
  17. Gordon ED, Locksley RM, Fahy JV. Cross-Talk between Epithelial Cells and Type 2 Immune Signaling. The Role of IL-25. Am J Respir Crit Care Med. 2016 May 01; 193(9):935-6.
  18. Sweerus K, Lachowicz-Scroggins M, Gordon E, LaFemina M, Huang X, Parikh M, Kanegai C, Fahy JV, Frank JA. Claudin-18 deficiency is associated with airway epithelial barrier dysfunction and asthma. J Allergy Clin Immunol. 2017 Jan; 139(1):72-81.e1.
  19. Kerr SC, Fischer GJ, Sinha M, McCabe O, Palmer JM, Choera T, Lim FY, Wimmerova M, Carrington SD, Yuan S, Lowell CA, Oscarson S, Keller NP, Fahy JV. FleA Expression in Aspergillus fumigatus Is Recognized by Fucosylated Structures on Mucins and Macrophages to Prevent Lung Infection. PLoS Pathog. 2016 Apr; 12(4):e1005555.
  20. Reber LL, Fahy JV. Mast cells in asthma: biomarker and therapeutic target. Eur Respir J. 2016 Apr; 47(4):1040-2.

Publications are derived from MEDLINE/PubMed and provided by UCSF Profiles, a service of the Clinical & Translational Science Institute (CTSI) at UCSF. Researchers can make corrections and additions to their publications by logging on to UCSF Profiles.