What describes chronic lymphocytic leukemia (CLL)?

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of mature lymphocytes, specifically B lymphocytes, in the blood and bone marrow. In CLL, these lymphocytes are functionally incompetent, meaning they are not effective in fighting infections, even though they are mature. This accumulation leads to the characteristic features of the disease, including lymphocytosis (an increased number of lymphocytes in the bloodstream) and potential complications arising from the impaired immune response.

The other options describe features that do not align with the nature of CLL. Infestation by immature lymphocytes refers more to acute types of leukemia, where there is a proliferation of immature cells. The rapid growth of lymphatic tumors is a characteristic of aggressive hematological malignancies, whereas CLL typically has a slower course. Finally, while some patients can be asymptomatic (asymptomatic CLL is possible), the statement about the absence of symptoms in all patients is misleading, as symptoms can develop over time, and many patients do experience symptoms as the disease progresses.