Inflammatory cells

Inflammatory cells are specialized types of white blood cells that migrate into tissues in response to changes, such as an injury, infection, or cancer. Their job is to protect you by fighting germs, removing damaged tissue, and aiding in the healing process. When a pathologist examines a tissue sample under the microscope, they may describe the presence of inflammatory cells in your pathology report.

What types of inflammatory cells are there?

There are several main types of inflammatory cells, each with a different role in the immune system:

• Neutrophils are usually the first cells to arrive at the site of infection or injury. They are especially important for fighting bacteria.

• Lymphocytes help control the immune response. B lymphocytes make antibodies, while T lymphocytes can directly attack infected or abnormal cells.

• Plasma cells are a type of B lymphocyte that produce large amounts of antibodies.

• Macrophages start as monocytes in the blood and then move into tissues, where they “clean up” debris, dead cells, and germs.

• Eosinophils are involved in allergic reactions and play a role in defense against parasites.

• Mast cells release chemicals such as histamine that cause swelling and attract other inflammatory cells.

What is the difference between acute and chronic inflammatory cells?

Pathologists often describe inflammation as acute or chronic depending on the types of cells they see and how long the process has been going on.

• Acute inflammation happens quickly, usually within hours to days. It is often caused by sudden injury or infection. The main cells in acute inflammation are neutrophils. These cells are fast-acting defenders that arrive first to attack bacteria and clean up dead tissue. Under the microscope, acute inflammation appears as a dense collection of neutrophils, often accompanied by pus formation.

• Chronic inflammation develops more slowly and can last for weeks, months, or even years. It often occurs when the body is dealing with long-term infections, autoimmune diseases, or ongoing irritation. The main cells in chronic inflammation are lymphocytes, plasma cells, and macrophages. These cells coordinate a longer-term immune response, produce antibodies, and repair or remodel damaged tissue. Under the microscope, chronic inflammation shows a mix of these cells and may cause scarring (fibrosis).

Understanding whether inflammation is acute or chronic helps your doctor know if your body is responding to a short-term problem or a longer-lasting condition.

Why might inflammatory cells be seen in my pathology report?

Inflammatory cells are often described in pathology reports because they can give important clues about the underlying condition. For example:

• Infection: Neutrophils are often increased in bacterial infections, whereas lymphocytes are more commonly found in viral infections.

• Autoimmune disease: Inflammatory cells can attack the body’s own tissues, as in lupus or rheumatoid arthritis.

• Allergic reactions: Eosinophils and mast cells are often present in conditions such as asthma or allergic dermatitis.

• Cancer: Sometimes inflammatory cells gather around tumors, either as part of the body’s defense or as a reaction to the cancer.

Questions to ask your doctor

• What kind of inflammatory cells were found in my sample?

• Does this mean I have an infection, an autoimmune disease, or another condition?

• Are the inflammatory cells part of a short-term (acute) or long-lasting (chronic) process?

• Do I need additional tests to find out why these cells are present?

• How will this information affect my treatment or follow-up care?