Cells of origin of CLL can be 2

NEET PG
#1

Cells of origin of CLL can be 2 :

  1. naive B cell when it comes out of marrow and wants to go to LN for maturation and activation but fail to enter LN due to abnormal mutation like del 13q : and this naive B cell starts proliferating in blood causing chronic lymphocytic leukemia . This variety is more common .

  2. post germinal centre memory B cell in marginal Zone : here these cells are activated and mature due to somatic hyper-mutation which happened in Germinal centre : and now these cells somehow start proliferating abnormally causing Small Lymphocytic Lymphoma : eventually if they come into blood and cause Monoclonal Lymphocytosis with Absolute Lymphocytes count >5000cells /microL : we will call it now SLL/CLL ( and it has better prognosis as these cells which has flodded from LN to blood are mature and activated unlike Naive b cells )