Neutropenia is a very rare blood condition that causes a reduced number or complete lack of neutrophils. Neutrophils are a type of blood cell that defends the body against bacterial infections.
Types of neutropenia include: congenital, idiopathic, cyclic and autoimmune. Symptoms patients experience depend on the level of neutropenia. The lower the neutrophil count, the greater the risk of infection. Infections can be life threatening and it is important the patient be seen by a doctor as soon as possible if the patient shows any signs or symptoms of an infection.
THE BODY AND BLOOD
The medical term for the formation of blood cells is haematopoiesis. Formation takes place in the marrow inside bones like the pelvic bone and the breastbone.
There are three basic types of blood cells:
Red Blood Cells: Also called erythrocytes, they carry oxygen to all other tissues of the body. About 3 million red blood cells are produced every second. These cells live and carry oxygen effectively for about four months.
Platelets: Also called thrombocytes, they are essential for the clotting of the blood. Most platelet clotting happens at the point of an injury such as a scratch or cut. They effectively reduce or stop the loss of blood from an injury. Normal counts are 150 and 400 million per milliliter of blood.
White Blood Cells: Also called leukocytes, this group of cells is responsible for fighting infections in the body. About 120,000 while blood cells are produced every second. There are three types of white blood cells: granulocytes, monocytes, and lymphocytes. Neutrophils make up most of the granulocytes.
NEUTROPHILS AND NEUTROPENIA
Neutrophils are the type of white blood cell that attack bacteria in the blood (see video below). There a few different reasons a person could develop neutropenia. Patients on chemotherapy can become neutropenic. Often these patients will revert to normal neutrophil levels should chemotherapy cease. Certain viral infections are also sometimes the cause. Others are simply born with the condition or the reason may not be known.
NEUTROPHILS IN ACTION
This video is taken from a 16-mm movie made in the 1950s by the late David Rogers at Vanderbilt University. It was given to us via Dr. Victor Najjar, Professor Emeritus at Tufts University Medical School and a former colleague of Rogers. It depicts a human polymorphonuclear leukocyte (neutrophil) on a blood film, crawling among red blood cells, notable for their dark color and principally spherical shape.
In the video above, the neutrophil is “chasing” Staphylococcus aureus microorganisms, added to the film. The chemoattractant derived from the microbe is unclear but may be complement fragment C5a, generated by the interaction of antibodies in the blood serum with the complement cascade, and/or bacterial N-formyl peptides. Blood platelets adherent to the underlying glass are also visible. Notable is the characteristic asymmetric shape of the crawling neutrophil with an organelle-excluding leading lamella and a narrowing at the opposite end culminating in a “tail” that the cell appears to drag along. Contraction waves are visible along the surface of the moving cell as it moves forward in a gliding fashion. As the neutrophil relentlessly pursues the microbe it ignores the red cells and platelets. However, its leading edge is sufficiently stiff (elastic) to deform and displace the red cells it bumps into. The internal contents of the neutrophil also move, and granule motion is particularly dynamic near the leading edge. These granules only approach the cell surface membrane when the cell changes direction and redistributes its peripheral “gel.” After the neutrophil has engulfed the bacterium, note that the cell’s movements become somewhat more jerky, and that it begins to extend more spherical surface projections. These bleb-like protruberances resemble the blebs that form constitutively in the M2 melanoma cells missing the actin filament crosslinking protein filamin-1 (ABP-280) and may be telling us something about the mechanism of membrane protrusion.
The duration of neutropenia may be short lived; however, should someone have neutropenia symptoms consistently for longer than three months they are considered to be suffering from chronic neutropenia.
NEUTROPHIL LEVELS
Normal level: 1500 to 7000 neutrophils per mm3 of blood.
Mild Neutropenia: when the ANC falls below a lower limit of 1500 per mm3 (1.5 x 109/l), but remains higher than 1000 per mm3 (1.0 x 109/l).
Moderate Neutropenia: when the ANC falls between 500 per mm3 and 1000 per mm3 (0.5 x 109/l – 1.0 x 109/l).
Severe Neutropenia: when the ANC falls below 500 per mm3 (0.5 x 109/l).
Symptoms patients experience depend on the level of neutropenia. The lower the neutrophil count, the greater the risk of infection. This risk increases if low neutrophil counts persist for more than three days. Types of infection include otitis media; tonsillitis; sore throat; mouth ulcers; gum infection and skin abscesses. Any fever above 38.5°C/101.3°F must be taken very seriously and your nurse or physician should be informed.
Severe neutropenia can lead to serious problems, which require prompt care since the patient could potentially develop a bacterial, fungal or mixed infection at any time. These infections can be life threatening and it is therefore important the patient be seen by a doctor as soon as possible that if the patient develops any signs or symptoms of an infection. They should then be treated with medications such as antibiotics to fight the infection.
