What characterizes the disease cells seen in chronic lymphocytic leukemia (CLL)?

Chronic lymphocytic leukemia (CLL) is characterized by the presence of smudge cells, which are fragile, damaged lymphocytes that appear during the microscopic examination of blood smears. These cells result from the rupture of lymphocytes due to their altered morphology and increased fragility in the setting of CLL.

Smudge cells are indicative of the disease because they signify the accumulation of these dysfunctional B lymphocytes, which are the hallmark of CLL. The presence of smudge cells can aid in the diagnosis and monitoring of the disease, as they correlate with the leukemic process occurring in CLL patients.

Regarding the other options, Reed-Sternberg cells are associated with Hodgkin's lymphoma, blast cells are indicative of acute leukemias, and the absence of lymphocytes would suggest a different pathology not characteristic of CLL, where we expect to see elevated lymphocyte counts. Therefore, smudge cells serve as a significant morphological feature in diagnosing and understanding the progression of chronic lymphocytic leukemia.