Question

The lymphocytopenia seen a few hours after administration of a large dose of prednisolone to a patient with lymphocytic leukemia is due to

• A. Massive lymphocyte apoptosis
• B. Bone marrow depression
• C. Activation of cytotoxic cells
• D. Stimulation of Natural killer cell activity

Hint:

Steroids trigger apoptosis in lymphocytes, and leukemic lymphocytes are highly sensitive to this effect.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks why a big dose of prednisolone, a glucocorticoid, causes the lymphocyte count to fall within hours in a patient who has lymphocytic leukemia.

Step 2: Key Formula or Approach:
Glucocorticoids act on lymphocytes in two ways. Within hours they cause redistribution of lymphocytes out of the blood into lymph nodes, spleen and bone marrow, and they also trigger programmed cell death, called apoptosis, in lymphocytes. Malignant lymphocytes in lymphocytic leukemia are especially sensitive to this apoptotic effect, which is why steroids are actually part of leukemia treatment.

Step 3: Detailed Explanation:
A large dose of prednisolone switches on genes inside the lymphocyte that push the cell toward apoptosis, a controlled form of cell death. Leukemic lymphocytes carry glucocorticoid receptors in high numbers, so they die off quickly and in large numbers once exposed to the steroid. This massive apoptosis is what drops the blood lymphocyte count within hours, well before any effect on the bone marrow could show up.
Bone marrow depression from steroids, if it happens at all, takes much longer to develop and mainly affects marrow producing other cell lines, not an acute drop in circulating lymphocytes.
Activation of cytotoxic cells would raise immune activity, not explain a fall in the lymphocyte count itself, and steroids in fact suppress cytotoxic T cell activity rather than switch it on.
Stimulation of Natural killer cell activity is also incorrect, since glucocorticoids generally dampen immune cell activity rather than stimulate it, and NK cell stimulation would not explain a drop in lymphocyte numbers.

Step 4: Final Answer:
The rapid lymphocytopenia is caused by massive apoptosis of the leukemic lymphocytes, so the correct option is (A).