Andrew Leavitt, MD

Medical Director, Adult Blood and Marrow Laboratory
Department of Laboratory Medicine
+1 415 353-2737
Research Overview: 

Hematopoiesis is a life-long developmental process requiring maintenance of a precursor/stem cell pool, generation of adequate numbers of circulating mature blood cells, and the ability to individually modulate each developmental lineage in response to specific needs of the organism. My lab uses murine models to study megakaryocytopoiesis, the “branch” of hematopoiesis that produces circulating platelets. We are currently studying the role of the Raf family, especially Raf-1 and B-Raf, and Stat-5 signaling in megakaryocytopoiesis.

Platelets play a critical role in clot formation through the binding of fibrinogen by their surface integrin aIIbb3. The aIIbb3 on resting, circulating platelets is unable to bind fibrinogen until the platelet is activated by one or more platelet agonists, typically at the site of vascular injury. The activation of aIIbb3 results in increased affinity and avidity of aIIbb3 for its ligand and is called agonist-induced “inside-out” signaling. We have demonstrated that inside-out signaling is developmentally regulated during megakaryocytopoiesis and that megakaryocytes lacking the transcription factor NF-E2 fail to undergo agonist induced aIIbb3 inside-out activation. We are currently using various methods of differential expression analysis to identify the NF-E2 regulated genes that play a role in the aIIbb3 inside-out signaling. These gene products should provide useful targets for new classes of anti-platelet agents.

Primary Thematic Area: 
Developmental & Stem Cell Biology
Secondary Thematic Area: 
Research Summary: 
Hematopoietic Stem Cells and Megakaryocytopoiesis



Impact of Plerixafor Use at Different Peripheral Blood CD34+ Thresholds on Autologous Stem Cell Collection in Patients with Multiple Myeloma.

Biology of blood and marrow transplantation : journal of the American Society for Blood and Marrow Transplantation

Shah EE, Young RP, Wong SW, Damon LE, Wolf JL, Shah ND, Leavitt AD, Loeffler P, Martin TG

Clinical and laboratory features of autoimmune hemolytic anemia associated with immune checkpoint inhibitors.

American journal of hematology

Leaf RK, Ferreri C, Rangachari D, Mier J, Witteles W, Ansstas G, Anagnostou T, Zubiri L, Piotrowska Z, Oo TH, Iberri D, Yarchoan M, Salama AKS, Johnson DB, Leavitt AD, Rahma OE, Reynolds KL, Leaf DE

Mammary precancerous stem and non-stem cells evolve into cancers of distinct subtypes.

Cancer research

Bu W, Liu Z, Jiang W, Nagi C, Huang S, Edwards DP, Jo E, Mo Q, Creighton CJ, Hilsenbeck SG, Leavitt AD, Lewis MT, Wong STC, Li Y