Inflammatory cells are specialized components of the body’s defense system. They respond to injury or infection by removing harmful stimuli and initiating repair processes. These cells are involved in healing injured tissue and trapping germs or toxins.
What Are Inflammatory Cells?
Inflammatory cells are a diverse collection of immune cells that orchestrate the body’s inflammatory response. They originate primarily in the bone marrow and circulate throughout the bloodstream and tissues. Their main purpose is to protect against invading pathogens and facilitate the repair of damaged tissues. When the body encounters a threat, these cells are mobilized to the affected area. They work to contain damage and promote healing.
Key Types of Inflammatory Cells
Neutrophils are the first responders to injury or infection, arriving within minutes to hours. These white blood cells are efficient phagocytes, engulfing and digesting pathogens and cellular debris. Their presence characterizes the early, or acute, phase of inflammation.
Macrophages are larger, longer-lived cells that arrive after neutrophils. They perform phagocytosis, clearing away dead cells and pathogens. Macrophages also contribute to tissue repair by producing various signaling molecules.
Lymphocytes, including T cells and B cells, are involved in specific immunity and immune memory. T cells directly attack infected cells or coordinate other immune cells. B cells produce antibodies that target specific pathogens. These cells play a prominent role in prolonged inflammatory responses.
Mast cells are found in tissues throughout the body and release histamine and other mediators. This release contributes to the redness, swelling, and itching associated with allergic reactions. Mast cells are also involved in the initial sensing of pathogens and tissue damage.
Eosinophils are associated with parasitic infections and allergic reactions. They release substances that can damage parasites and contribute to the inflammatory response seen in conditions like asthma. Basophils, similar to mast cells, also release histamine and are involved in allergic responses.
Their Role in the Immune Response
Inflammatory cells work together in a coordinated manner during both acute and chronic inflammation. Acute inflammation is the body’s immediate response to sudden injury or infection, lasting from a few hours to several days. During this phase, resident immune cells like macrophages and mast cells detect threats and release signaling molecules.
These signals cause blood vessels to widen and become more permeable, allowing inflammatory cells to travel to the site of injury. Neutrophils are among the first to arrive, engulfing pathogens and releasing substances that attract more immune cells. This localized response helps to trap germs or toxins and initiate the healing process.
Chronic inflammation, in contrast, can persist for months or even years. This prolonged response often involves a shift in the types of cells present, with macrophages, lymphocytes, and plasma cells becoming more dominant. In chronic inflammation, the sustained activity of these cells can contribute to ongoing tissue damage and prevent proper healing.
When Inflammatory Cells Go Wrong
While inflammatory cells are protective, their dysregulation can lead to various health problems. When the inflammatory response becomes excessive or misdirected, it can harm healthy tissues. This uncontrolled activity is a factor in numerous chronic conditions.
Autoimmune diseases, such as rheumatoid arthritis and lupus, occur when inflammatory cells mistakenly attack the body’s own tissues. For instance, in rheumatoid arthritis, inflammatory cells can attack joint tissues, leading to damage. Allergies and asthma also involve misdirected inflammatory responses, where the immune system overreacts to harmless substances like pollen or dust.
Chronic inflammation is also linked to a range of other chronic diseases, including heart disease, certain cancers, and neurodegenerative conditions. In these cases, the persistent presence and activity of inflammatory cells can contribute to disease progression and tissue dysfunction.