Stephanie Sasse, Katharina Reddemann, Arjan Diepstra, Ilske Oschlies, Antje Schnitter, Sven Borchmann, Andreas Engert, Peter Borchmann and Wolfram Klapper (2018) “Programmed cell death protein-1 (PD-1)-expression in the microenvironment of classical Hodgkin lymphoma at relapse during anti-PD-1-treatment”, Haematologica. Pavia, Italy, 104(1), pp. e21-e24. doi: 10.3324/haematol.2018.196279.