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

Answer is B (Results from an expansion of Neoplastic T lymphocytes) Hairy cell leukemia ica 'B' cell neoplasm and is characterked by expansion of neoplasticB cells (not T lymphocytes) Hairy cell leukemia: Hairy cell leukemia is a rare but distinctive form of chronic B cell leukemia that derives its name from the appearance of fine 'hair like projectionsdeg on the leukaemic cells (large B cells) * Characteristic cytochemical feature: Presence of tarate resistant acid phosphatase 'TRAP' 0 in neoplastic B cells * Cellular features/ Markers * Hairy cells express the pan B cell markers CD 19 and CD 20 and monocyte associated antigen CD 11 * Plasma cell associated antigen ( PCA-1) is also present - Robbins * Expression of CD 25, IL2 and specific adhesion molecules - Harrison 14th/695 * Clinical features * Present predominantly in the older age group > 40 yearsdeg result largely from infiltration of bone * Massive splenomegalydeg (hepatomegaly is less common) marrow liver and spleen * Lymphadenopathy * PancytopeniaQ * Recurrent infections * Treatment Q * Current treatment of choice is with purine analogues - Cladribinedeg * Other drugs used - Pentostotindeg - Interferon c(0 * Splenectomy used to be the standard treatment earlier