After 48 hours of inflammation, the predominant cells are typically monocytes,
which differentiate into macrophages.
1. Neutrophils: Neutrophils are the most abundant type of white blood cells
and are the first to arrive at the site of inflammation. They are the primary
cells that dominate the early stages of acute inflammation, which typically
occurs within the first few hours (around 4-6 hours) after the onset of injury
or infection. Their main function is to phagocytose (engulf and destroy)
microbes and release enzymes and proteins that help to break down and dissolve
damaged tissue. Although they play a crucial role in the early stages, their
numbers tend to decrease after this initial phase, making them less likely to be
the predominant cells after 48 hours.
2. Monocytes: Monocytes are the largest of the white blood cells and are part of
the mononuclear phagocytic system. They are recruited from the bloodstream to
the site of inflammation in response to chemical signals called chemokines.
After approximately 24-48 hours of inflammation, monocytes start to predominate
the scene. These cells differentiate into macrophages once they have infiltrated
the tissue. Macrophages are the "clean-up crew" of the immune system, engaging
in phagocytosis, antigen presentation, and the release of cytokines that help
coordinate the overall inflammatory response. They are crucial for the later
stages of inflammation, which include the removal of debris, repair, and
resolution.
3. Eosinophils: Eosinophils are white blood cells that are involved in the
immune response to parasitic infections and in the pathogenesis of certain
allergic diseases. They are not typically the predominant cells in the general
inflammatory response and are more commonly associated with allergic
inflammation and parasitic infections. After 48 hours, eosinophils are less
likely to be the main cell type unless the inflammation is of an allergic or
parasitic nature, in which case they might be present in larger numbers.
However, in a typical non-specific inflammatory process, they are not the
predominant cell type after this duration.
4. Lymphocytes: Lymphocytes are a type of white blood cell that is essential for
the adaptive immune response. There are two main types: T-lymphocytes and
B-lymphocytes. While they are involved in the later stages of inflammation,
particularly in the adaptive immune response, they are not typically the
predominant cells after 48 hours in a general acute inflammatory setting.
Lymphocytes are more likely to be found in higher numbers during the later
stages of inflammation, particularly during the resolution phase or in chronic
inflammation, when the body is mounting a more specific response to the invading
pathogen.
