Dr. Sytse Piersma joined the Department of Medicine in the Division of Rheumatology as an Instructor in September, 2019.
Dr. Piersma’s research focuses on understanding Natural Killer cell activation, in particular in response to virus infection and cancer. Dr. Piersma completed his PhD under supervision of Prof. Dr. Sjoerd van der Burg and Dr. Cornelis Melief in the field of tumor immunology, where he studied tumor infiltration by lymphocytes in patients with human papilloma virus (HPV)-induced cervical cancer. The main breakthroughs are the discovery of the clinical impact of CD8+ T cells in cervical cancer patients and the identification of HPV-specific T-regulatory cells in tumor-biopsies.
During his postdoctoral training in the lab of Wayne Yokoyama, Dr. Piersma investigated the requirements for NK cell activation, during which he was supported by the prestigious NWO Rubicon fellowship. His work illustrated that type I interferons (IFN-I) and IL12 produced during virus infection are critical for NK cell-mediated lysis of virus infected cells. Production of the NK signature cytokine Interferon-γ upon target cell recognition also required IFN-I or IL12. Furthermore, he investigated the pathways that are responsible for IFN-I production during cytomegalovirus infection in distinct cell types and found that infected plasmacytoid dendritic cells produced IFN-I in a Toll like receptor-dependent manner while stromal cell IFN-I was dependent on cGAS and STING. Taken together, his findings revealed a stepwise activation process for NK cell effector functions and the involved pathways represent potential targets for NK cell therapies.
Dr. Piersma has spent a sabbatical in the Netherlands exploring NKG2A as a novel immune checkpoint on T cells. He found that NKG2A was expressed on tumor infiltrating T cells while its ligand Qa1 was expressed on tumor cells, in particular in response to immunotherapy. His work resulted in a project that was funded by the Dutch cancer society (KWF), on which he was listed as co-PI.