N Porakishvili, L Kardava, AP Jewell, K Yong, MJ Glennie, A Akbar, PM Lydyard. Cytotoxic CD4+ T cells in patients with B cell chronic lymphocytic leukemia kill via a perforin-mediated pathway. Haematologica 2004;89(4):435-443; https://doi.org/10.3324/%x.