Why do infants have high lymphocyte count?

Newborns have a higher total white blood cell (WBC) count than adults, but this count typically decreases during the first few weeks of life. The absolute lymphocyte count (ALC) may be slightly higher in newborns than in adults, but the relative lymphocyte count (RLC) is typically lower.

The higher ALC in newborns is likely due to a combination of factors, including:

- Increased production of lymphocytes in the thymus gland

- Decreased apoptosis (cell death) of lymphocytes

- Increased circulation of lymphocytes from the bone marrow to the blood

The lower RLC in newborns is likely due to the higher number of neutrophils, which are a type of WBC that helps to fight bacterial infections.

The WBC and ALC counts in newborns are typically monitored closely to ensure that they are within normal ranges. If these counts are too high or too low, it may be a sign of an underlying medical condition.