Scanning electron micrograph of 'hairy cell' leukaemia (HCL) showing B lymphocytes and red blood cells. It was previously thought that 'hairy cell' leukaemia was due to the malignant proliferation of histiocytic cells, but these cells are now thought to be B cells. Leukaemia is a malignant disease in which the bone marrow & other blood-forming organs overproduce certain types of white blood cell. These immature & abnormal cells suppress normal production of white & red cells, thereby increasing the susceptibility to infections such as anaemia. Magnification: x6000 at 10x8 inch size.