All of the following are true regarding CLL except: March 2008

Ans. D: Affects T-cellsB-cell chronic lymphocytic leukemia (B-CLL)/chronic lymphoid leukemia (CLL), is the most common type of leukemia of the adults.CLL affects B cell lymphocytes.B cells originate in the bone marrow, develop in the lymph nodes, and normally fight infection by producing antibodies. In CLL, the DNA of a B cell is damaged, so that it can't produce antibodies. Additionally, B cells grow out of control and accumulate in the bone marrow and blood, where they crowd out healthy blood cells.Most (>75%) people newly diagnosed with CLL are over the age of 55, and the majority are men.Most people are diagnosed without symptoms as the result of a routine blood test that returns a high white blood cell count, but, as it advances, CLL results in swollen lymph nodes, spleen, and liver, and eventually anemia and infections. DNA analysis has distinguished two major types of CLL, with different survival times.CLL that is positive for the marker ZAP-70 has an average survival of 5 years.CLL that is negative for ZAP-70 has an average survival of more than 25 years.