Agranulocytosis is a low level of white blood cells. These blood cells are part of the immune system. They help fight infections.

Agranulocytosis may be:

  • Acquired—Develops after medical treatment or specific drugs. May appear suddenly or develop over time.
  • Congenital—present at birth
    • Cyclic neutropenia—cycles up and down over a 21-day period
    • Severe congenital neutropenia

White Blood Cells
White Blood Cells
Copyright © Nucleus Medical Media, Inc.

Agranulocytosis is caused by destruction of white blood cells or by the failure of bone marrow to make enough white blood cells.

With congenital agranulocytosis, these problems are caused by a genetic defect.

With acquired agranulocytosis, these problems may be caused by:

  • Infections by virus, bacteria, or parasite
  • Underlying inflammatory condition
  • Chemotherapy
  • Drugs—used in medical treatment or recreational use
  • Autoimmune disease—your immune systems attacks your own tissue such as white blood cells
  • Damage to bone marrow usually by chemicals, radiation, or cancers
  • Certain toxins
  • Poor nutrition—particularly low protein intake