Angiogenesis occurs in hairy cell leukaemia (HCL) and in NOD/SCID mice transplanted with the HCL line Bonna-12

Microvessel density (MVD), a surrogate marker for angiogenesis, was evaluated by anti-CD34 and CD105 monoclonal antibodies (Abs), and found to be increased in the bone marrow (BM) of hairy cell leukaemia (HCL) patients and in a preclinical model of non-obese diabetice/severe combined immunodeficient mice transplanted with the HCL line Bonna-12. The anti-CD105 Ab was significantly more sensitive than anti-CD34 Ab in identifying blood vessels. The BM tumour burden significantly decreased in patients treated with interferon-alpha, but the mean value of MVD remained unchanged. These data suggest that angiogenesis may be involved in the pathogenesis of HCL.