Defective Natural Killer Cell Activity in B-Cell Chronic Lymphocytic Leukaemia Is Associated with Impaired Release of Natural Killer Cytotoxic Factor(s) but Not of Tumour Necrosis Factor-αGeorge Katrinakis, George D. Eliopoulos, Despina Kyriakou et al.|Acta Haematologica|2009Cited by 53