How quickly do lymphocytes reduce in numbers after radiation exposure?

Lymphocytes are a type of white blood cell that plays a crucial role in the immune response. After radiation exposure, particularly ionizing radiation, lymphocytes are among the most sensitive cells due to their high mitotic rate and the essential functions they serve in the immune system.

Following radiation exposure, the reduction in the number of lymphocytes occurs quite rapidly. It is well-documented that lymphocyte counts can significantly drop within minutes to hours after exposure due to the immediate effects of radiation on these cells. The radiation induces damage to the DNA, leading to cell death or dysfunction of lymphocytes.

The choices that suggest a timeframe of days to weeks, hours to months, or instantly provide inaccurate representations of the biological response to radiation in terms of lymphocyte depletion. The correct timeframe recognizes the immediate impact radiation has, which aligns with the physiological understanding of how rapidly these immune cells are affected in a radiation context.