Rachael A. Clark, MD, PhD (Damon Runyon Clinical Investigator ‘08-‘13) of Brigham and Women’s Hospital, Boston, and colleagues reported that the drug Campath (alemtuzumab) effectively treats patients with Leukemic cutaneous T-cell lymphoma (L-CTCL), a leukemia arising from a type of white blood cell called T-cells. This cancer can involve the skin and other organs, and patients often die within three years. The researchers demonstrated that Campath only kills T-cells that enter the bloodstream, including the cancerous T-cells; it spares a newly discovered population of immune cells called tissue resident T-cells that provide the patient with immunity against infections. This study is the first demonstration in humans that tissue resident T-cells provide crucial immune protection of the skin.  The findings were published in the journal Science Translational Medicine.