All of the following statements about Hairy cell leukaemia are true, EXCEPT:

Hairy cell leukemia is an uncommon B cell lymphoproliferative disorder. It constitute 2% of all forms of leukemia. Median age of occurrence is 55years. Male to female ratio is 4.5:1. Most patients are asymptomatic and are diagnosed following an incidental finding of spleenomegaly or cytopenia. Some can present with fatigue, weakness, weight loss and occasionally fever and night sweats. Ref: Oxford Desk Reference Oncology By Thankamma V. Ajithkumar, Page 486